Langley DAAC Version Number:        LD_008_015_002_00_00_0_19990609



                               MAPS Readme

1.0  Introduction

This file contains information about the Measurement of Air Pollution from 
Satellites (MAPS) sample read software and data files. The table below lists 
for all of the data sets available through the Langley DAAC, the format 
of the data sets and if sample read software is also available. The data sets
appear in the order as they became available to the user community. These are 
the data sets that are available through the Langley DAAC:

This table lists all data sets available through the Langley DAAC as well 
availability of sample read software.

Data Set Name	      Sample Read Software Availability	     Data Format
-------------         ---------------------------------      -----------
MAPS_OSTA3_CO5X5_HDF	            Yes	                         HDF
MAPS_SRL1_CO5X5_HDF	            Yes	                         HDF
MAPS_SRL2_CO5X5_HDF	            Yes                 	 HDF
MAPS_OSTA3_COSEC_HDF	            Yes	                         HDF
MAPS_SRL1_COSEC_HDF	            Yes	                         HDF
MAPS_SRL2_COSEC_HDF	            Yes	                         HDF
MAPS_OSTA3_LVL1_HDF	            Yes	                         HDF
MAPS_SRL1_LVL1_HDF	            Yes	                         HDF
MAPS_SRL2_LVL1_HDF	            Yes	                         HDF

 This "readme" file includes the following five other sections:
    Section 2.0 - describes all sample C programs (source files).
    Section 3.0 - discusses how to create the executables from the C programs.
    Section 4.0 - demonstrates how to invoke the run-time executables.
    Section 5.0 - provides general information on the data sets.
    Section 6.0 - provides more detailed implementation notes.

If users have questions while using the MAPS sample read software, please 
contact the Langley User and Data Services office. 

EOSDIS Langley DAAC 
Science, Users and Data Services Office
NASA Langley Research Center
Mail Code 157D
2 South Wright Street
Hampton, Virginia 23681-2199
U.S.A.

E-mail:   larc@eos.nasa.gov
Phone:    (757)864-8656
FAX:      (757)864-8807


2.0  Read Software Files

Currently, there is one sample read program for the MAPS data sets. This code 
is written in the C language. This C program has been tested on the Sun,SGI,
Dec Alpha, and HP UNIX-based workstations. All library functions in the C 
source codes are tested for ANSI C conformance. C shell scripts are included 
for the convenience of creating the executable files from the C source files. 
These files and their purposes are listed as follows:

compile_read_maps_co5x5 - contains a set of commands to build the run-time 
                    executable for the 5 by 5 grid box data sets.

maps_co5x5_read.c - reads the MAPS Carbon Monoxide 5 by 5 degree grid boxes 
                    formatted files that were written using the HDF extensions. 
                    This code is written in the C language.

compile_read_maps_cosec - contains a set of commands to build the run-time 
                    executable for the second by second point data data sets.

maps_cosec_read.c - reads the MAPS Carbon Monoxide second by second point data 
                    files that were written using the HDF extensions. This 
                    code is written in the C language.

compile_read_maps_lvl1 - contains a set of commands to build the run-time 
                    executable for the level 1 data data sets.

maps_lvl1_read.c -  reads the MAPS level 1 data files that were written using 
                    the HDF extensions. This code is written in the C language.


3.0  Creating C Executable Files

The following sections describe how to create the executables for the HDF. 

3.1 Creating the Executables for the HDF data format files

The user has two methods of building the sample read programs from the source
files. The user is able to build the code from the command line or for
conveince, build the code using the C shell script that was provided with
the sample read software.  All files are defined in Section 2.0.  Users
working with the HDF data format files need the HDF libraries in order to
build the executable for the sample read software.

HDF information, documentation, tutorials, libraries, etc. can be found 
on-line at the URL:

	http://hdf.ncsa.uiuc.edu

A utility (hdp) is provided in the HDF libraries which will extract information
about the contents of the HDF file. The commands:

hdp -H
hdp dumpsds [-options] <HDF file name>
hdp dumpvd [-options] <HDF file name>
vshow <HDF file name> [+|+vdata_id]

These will give information as to the size, type, and names of
the HDF data structures. The [-H] option will give help information.

Download the HDF libraries from the NCSA web site
( http://hdf.ncsa.uiuc.edu ).  This code uses Version HDF4.1r2.
Other versions of the HDF libraries may not work with this code.  NCSA uses 
the gnu gzip compression utility for some packages.  If you do not already 
have this software which is needed to uncompress the file, you can obtain it 
from one of the Gnu mirror sites listed at
   	http://www.gnu.org/order/ftp.html

Once all of the HDF libraries are located on your system, you are now 
ready to compile the sample read software.

Currently, the Langley DAAC is working with Versions 4.1r1 and 4.1r2 of the
HDF library.

3.1.1 Create an executable using the C shell scripts

The files that contain the C shell scripts are those files that begin with
the word "compile" in the file name. To build the executable that reads
the HDF data format files for the MAPS, you must obtain the compile script
which is for your particular data set.  The scripts are called 
compile_read_maps_co5x5, compile_read_maps_cosec, and 
compile_read_maps_lvl1.

Refer to (edit) the sample script 'compile_read_maps_co5x5' to link the HDF 
libraries and compile the C program. Check the permissions on this file to 
make sure execute permission is set for the owner:
   	ls -l compile_read_maps_co5x5
   	ls -l compile_read_maps_cosec
   	ls -l compile_read_maps_lvl1
should display something like
   -rwxr--r--   1 OWNER     GROUP        4077 Feb  3 00:44 compile_read_maps_co5x5
   -rwxr--r--   1 OWNER     GROUP        4077 Feb  3 00:44 compile_read_maps_cosec
   -rwxr--r--   1 OWNER     GROUP        4064 Feb  3 00:44 compile_read_maps_lvl1
where OWNER and GROUP are the file owner and group information.
The owner executable permission is the x in -rwxr--r--.  To set proper
permissions (assuming you are the file owner), type
   	chmod 744 compile_read_maps_co5x5

Execute the script 'compile_read_maps_co5x5' to create the executable by typing
   	source compile_read_maps_co5x5
or, on some systems you need only type
   	compile_read_maps_co5x5
   	compile_read_maps_cosec
   	compile_read_maps_lvl1

To run the executable at the command line, just type:
     read_maps_co5x5
     read_maps_cosec
     read_maps_lvl1


**NOTE:  Please refer to the compile script that applies to the data set
that you would like to read.

Data Set Name                  Compile Script Name
-------------                  -------------------
MAPS_OSTA3_CO5X5_HDF           compile_read_maps_co5x5
MAPS_SRL1_CO5X5_HDF            compile_read_maps_co5x5
MAPS_SRL2_CO5X5_HDF            compile_read_maps_co5x5
MAPS_OSTA3_COSEC_HDF	       compile_read_maps_cosec
MAPS_SRL1_COSEC_HDF	       compile_read_maps_cosec
MAPS_SRL2_COSEC_HDF	       compile_read_maps_cosec
MAPS_OSTA3_LVL1_HDF	       compile_read_maps_lvl1
MAPS_SRL1_LVL1_HDF	       compile_read_maps_lvl1
MAPS_SRL2_LVL1_HDF	       compile_read_maps_lvl1

3.1.3 Create with the compiler

This method uses the combinations of the HDF libraries, the HDF includes 
files, and the programs provided for the data sets (maps_co5x5_read.c). To 
build the executable for these data sets, at the command line prompt type:

On your Sun system, the following command was used to build the sample
software:

gcc -o read_maps_co5x5 maps_co5x5_read.c -I/usr/local/hdf/include \
    -L/usr/local/hdf/lib -lmfhdf -ldf -ljpeg -lz -L/usr/lib

NOTE:  You will have to modify the paths for the HDF libraries to the
correct location on your system.


On your SGI Irix 6.2 system, the following command was used to build the sample
software:

cc -ansi -n32 -mips3 -O -s -o read_maps_co5x5 maps_co5x5_read.c  \
       -I/usr/people2/paula/HDF/4.1r2_irix6.2/include \
       -L/usr/people2/paula/HDF/4.1r2_irix6.2/lib -ldf -lz

NOTE:  You will have to modify the paths for the HDF libraries to the
correct location on your system. 


On your Dec Alpha V4.0A system, the following command was used to build the 
sample software:

cc -o read_maps_co5x5 maps_co5x5_read.c -I/usr/local/HDF4.1r1/include \
-L/usr/local/HDF4.1r1/lib -lmfhdf -ldf -ljpeg -lz -L/usr/lib 

NOTE:  You will have to modify the paths for the HDF libraries to the
correct location on your system.


On your HP system, the following command was used to build the sample
software:

gcc -o read_maps_co5x5 maps_co5x5_read.c -I/usr/local/HDF4.1r1/include \
-L/usr/local/HDF4.1r1/lib -lmfhdf -ldf -ljpeg -lz -L/usr/lib 

NOTE:  You will have to modify the paths for the HDF libraries to the
correct location on your system.

Remember that your paths on your system may be different than these listed
above. Please modify your paths accordingly.
     




4.0  Invoking Read Software

This section illustrates the invocation of the executable files. Section 4.1 
describes how to run the read program for the Carbon Monoxide 5 by 5 grid 
boxes data sets (MAPS_OSTA3_CO5X5_HDF, MAPS_SRL1_CO5X5_HDF, and 
MAPS_SRL2_CO5X5_HDF). Section 4.2 describes how to run the read program for the
Carbon Monoxide second by second data sets (MAPS_OSTA3_COSEC_HDF, 
MAPS_SRL1_COSEC_HDF, and MAPS_SRL2_COSEC_HDF). Section 4.3 describes how to run 
the read program for the level 1 data sets (MAPS_OSTA3_LVL1_HDF, 
MAPS_SRL1_LVL1_HDF, and MAPS_SRL2_LVL1_HDF).

4.1  Running the Read Program for the Carbon Monoxide 5 by 5 grid boxes Data 
     Sets

Currently, the executable maps_co5x5_read.c read program (C version) for the 
MAPS_OSTA3_CO5X5_HDF, MAPS_SRL1_CO5X5_HDF, MAPS_SRL2_CO5X5_HDF data sets do not
accept command line arguments. When this program is executed, it requests an 
input filename. The output file name is automatically created by appending 
".rpt" to the input file name. This code assumes that the data and code are 
located in the same area. The report file generated will also be included in 
the local working area. After entering the file name, the user is presented 
with a parameter selection list. At this point, the program generates the 
report file and exits. The following line will begin program execution:
		% read_maps_co5x5

A sample of the interactive program execution is provided in Section 6.0.

4.2  Running the Read Program for the Carbon Monoxide Second by Second Data Sets

Currently, the executable maps_cosec_read.c read program (C version) for the 
MAPS_OSTA3_COSEC_HDF, MAPS_SRL1_COSEC_HDF, MAPS_SRL2_COSEC_HDF data sets do not 
accept command line arguments. When this program is executed, it requests an 
input filename. The output file name is automatically created by appending 
".rpt" to the input file name. This code assumes that the data and code are 
located in the same area. The report file generated will also be included in the
local working area. After entering the file name, the user is presented with a 
parameter selection list. At this point, the program generates the report file 
and exits. The following line will begin program execution:
		% read_maps_cosec

A sample of the interactive program execution is provided in Section 6.0.

4.3  Running the Read Program for the Level 1 Data Sets

Currently, the executable maps_cosec_read.c read program (C version) for the 
MAPS_OSTA3_LVL1_HDF, MAPS_SRL1_LVL1_HDF, MAPS_SRL2_LVL1_HDF data sets do not 
accept command line arguments. When this program is executed, it requests an 
input filename. The output file name is automatically created by appending 
".rpt" to the input file name. This code assumes that the data and code are 
located in the same area. The report file generated will also be included in 
the local working area. After entering the file name, the user is presented 
with a parameter selection list. At this point, the program generates the report
file and exits. The following line will begin program execution:
		% read_maps_lvl1

A sample of the interactive program execution is provided in Section 6.0.


5.0  Data Sets Information

The following subsections provide information the MAPS data sets on-line at the 
Langley DAAC.

DATA SET NAME	       SECTION
-------------          -------
MAPS_OSTA3_CO5X5_HDF	5.1
MAPS_SRL1_CO5X5_HDF	5.2
MAPS_SRL2_CO5X5_HDF	5.3
MAPS_OSTA3_COSEC_HDF	5.4
MAPS_SRL1_COSEC_HDF	5.5
MAPS_SRL2_COSEC_HDF	5.6
MAPS_OSTA3_COSEC_HDF	5.7
MAPS_SRL1_COSEC_HDF	5.8
MAPS_SRL2_COSEC_HDF	5.9

 
Each set of data set's information was obtained from the data files, documents, 
or directly from the data producer/provider. The high-level data set 
descriptions, the data files, the variables in the data files, and the contacts 
for data production are given under each data set. Some data sets contain the 
data producer's/provider's responses to questions on the data contents. These 
questions and/or responses are collected under the "NOTES ON DATA" section.

5.1  MAPS_OSTA3_CO5X5_HDF Data Set
This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:    Measurement of Air Pollution from Satellites 
                                (MAPS) Office of Space and Terrestrial 
                                Applications - 3 (OSTA3) Carbon Monoxide 5 
                                degree by 5 degree data in Hierarchical 
                                Data Format (HDF) (MAPS_OSTA3_CO5X5_HDF)

FILE NAMING CONVENTION:         MAPS_OSTA3_CO5X5_HDF data set files are prefixed
                                with "osta35x5" to indicate they belong to this 
                                data set. This is followed by a four digit 
                                number (mmdd) that represents the month and the 
                                start day the data were collected. The name is 
                                then followed by an underscore and another two 
                                digit number that represents the end day the 
                                data were collected for a particular granule. 
                                The name ends with an underscore followed by 
                                the letters "hdf." These three letters inform 
                                the user that the data are written in HDF.

VARIABLES:                      This data set contains 5 HDF scientific data 
                                sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Longitude	Degrees
	Latitude	Degrees
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	Counts	Number Points per Average

NOTES ON DATA:                 Dimension lengths show above may vary between 
                               files due to variations in the amount of data 
                               collected per flight track.

                               Data are not available for dates October 8 - 9, 
                               1984. There were temperature problems with the 
                               platform and therefore MAPS did not collect data 
                               for those two days.

                               Grids are referenced on 5 degree boxes starting 
                               in the lower left corner.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Sample data from the osta35x5_1006_06_hdf file:
This is from the report file for the osta35x5_1006_06_hdf file.
*************************** LONGITUDE NO. 1 ******************************

Longitude:
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00

Latitude:
          65.00          60.00          55.00          50.00          45.00
          40.00          35.00          30.00          25.00          20.00
          15.00          10.00           5.00           0.00          -5.00
         -10.00         -15.00         -20.00         -25.00         -30.00
         -35.00         -40.00         -45.00         -50.00         -55.00
         -60.00         -65.00         -70.00

CO:
        -777.77           0.00         121.05           0.00          71.21
          68.13          72.57           0.00          54.02          55.55
           0.00           0.00          56.34          57.91           0.00
           0.00          76.01          91.99           0.00         121.01
          98.30          79.49          92.62           0.00           0.00
          80.63        -777.77        -777.77

N2O:
        -777.77           0.00         365.12           0.00         273.06
         248.65         305.36           0.00         237.67         239.36
           0.00           0.00         280.62         285.19           0.00
           0.00         306.34         346.99           0.00         338.80
         296.31         243.36         298.29           0.00           0.00
         362.43        -777.77        -777.77

Counts:
        -777.77           0.00           5.00           0.00          55.00
          15.00           3.00           0.00           7.00          13.00
           0.00           0.00          17.00          60.00           0.00
           0.00          41.00          22.00           0.00           7.00
          62.00           7.00          34.00           0.00           0.00
          18.00        -777.77        -777.77

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. 
Thermal energy from the Earth passes through the atmosphere and enters the 
viewport of the downlooking MAPS instrument. Carbon monoxide and nitrous oxide 
(N2O) in the atmosphere produce unique absorption lines in the transmitted 
energy. The energy which enters the MAPS instrument is split into three beams. 
One beam passes through a cell containing CO and falls onto a detector. This 
CO gas cell acts as a filter for the effects of CO present in the middle 
troposphere. A second beam falls directly onto a detector without passing 
through any gas filter. The difference in the voltage of the signals from these 
two detectors can be used to determine the amount of CO present in the 
atmosphere at an altitude of 7-8 km. A third beam of the incident energy passes 
through a cell containing N2O and falls onto a detector. This N2O gas cell acts 
as a filter for the effects of N2O present in the atmosphere. The global 
distribution of N2O is well known, so the N2O signal can be used to detect the 
presence of clouds in the field of view and to correct the simultaneous CO 
measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.2  MAPS_SRL1_CO5X5_HDF Data Set

This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:     Measurement of Air Pollution from Satellites 
                                 (MAPS) Space Radar Laboratory - 1 (SRL1) Carbon
                                 Monoxide 5 degree by 5 degree data in 
                                 Hierarchical Data Format (HDF) 
                                 (MAPS_SRL1_CO5X5_HDF)

FILE NAMING CONVENTION:          MAPS_SRL1_CO5X5_HDF data set files are prefixed
                                 with "srl15x5" to indicate they belong to this 
                                 data set. This is followed by a four digit 
                                 number (mmdd) that represents the month and the
                                 start day the data were collected. The name is 
                                 then followed by an underscore and another two 
                                 digit number that represents the end day the 
                                 data were collected for a particular granule. 
                                 The name ends with an underscore followed by 
                                 the letters "hdf." These three letters inform 
                                 the user that the data are written in HDF.

VARIABLES:                       This data set contains 5 HDF scientific data 
                                 sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Longitude	Degrees
	Latitude	Degrees
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	Counts	Number Points per Average

NOTES ON DATA:                   Dimension lengths show above may vary between files due 
                                 to variations in the amount of data collected per flight 
                                 track.

                                 Grids are referenced on 5 degree boxes starting in the 
                                 lower left corner.


FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Sample data from the srl15x5_0409_09_hdf file:
This is from the report file for the srl15x5_0409_09_hdf file.

*************************** LONGITUDE NO. 1 ******************************


Longitude:
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00

Latitude:
          65.00          60.00          55.00          50.00          45.00
          40.00          35.00          30.00          25.00          20.00
          15.00          10.00           5.00           0.00          -5.00
         -10.00         -15.00         -20.00         -25.00         -30.00
         -35.00         -40.00         -45.00         -50.00         -55.00
         -60.00         -65.00         -70.00

CO:
        -777.77           0.00          95.37          92.63          93.51
          99.57           0.00         125.65           0.00           0.00
           0.00           0.00           0.00          57.35          68.50
           0.00           0.00         106.21         105.84           0.00
         125.89          83.71          90.69          82.26          88.80
          77.19        -777.77        -777.77

N2O:
        -777.77           0.00         311.54         317.94         309.87
         310.93           0.00         351.55           0.00           0.00
           0.00           0.00           0.00         248.63         282.03
           0.00           0.00         317.88         332.78           0.00
         333.67         303.63         308.20         300.40         307.73
         323.04        -777.77        -777.77

Counts:
        -777.77           0.00         134.00          68.00          41.00
           9.00           0.00           8.00           0.00           0.00
           0.00           0.00           0.00          36.00          21.00
           0.00           0.00          57.00           5.00           0.00
          11.00          88.00          69.00          39.00          69.00
          10.00        -777.77        -777.77
 

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. 
Thermal energy from the Earth passes through the atmosphere and enters the 
viewport of the downlooking MAPS instrument. Carbon monoxide and nitrous oxide 
(N2O) in the atmosphere produce unique absorption lines in the transmitted energy.
The energy which enters the MAPS instrument is split into three beams. One beam 
passes through a cell containing CO and falls onto a detector. This CO gas cell 
acts as a filter for the effects of CO present in the middle troposphere. A 
second beam falls directly onto a detector without passing through any gas 
filter. The difference in the voltage of the signals from these two detectors can 
be used to determine the amount of CO present in the atmosphere at an altitude 
of 7-8 km. A third beam of the incident energy passes through a cell containing 
N2O and falls onto a detector. This N2O gas cell acts as a filter for the effects 
of N2O present in the atmosphere. The global distribution of N2O is well known, 
so the N2O signal can be used to detect the presence of clouds in the field of 
view and to correct the simultaneous CO measurement for systematic errors in the
data.


CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.3  MAPS_SRL2_CO5X5_HDF Data Set
This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:      Measurement of Air Pollution from Satellites 
                                  (MAPS) Space Radar Laboratory - 2 Carbon 
                                  Monoxide 5 degree by 5 degree data in 
                                  Hierarchical Data Format (HDF) 
                                  (MAPS_SRL2_CO5X5_HDF)

FILE NAMING CONVENTION:           MAPS_SRL2_CO5X5_HDF data set files are prefixed 
                                  with "srl25x5" to indicate they belong to this 
                                  data set. This is followed by a four digit 
                                  number (mmdd) that represents the month and the 
                                  start day the data were collected. The name is 
                                  then followed by an underscore and another two 
                                  digit number that represents the end day the 
                                  data were collected for a particular granule. 
                                  The name ends with an underscore followed by the
                                  letters "hdf." These three letters inform the 
                                  user that the data are written in HDF.

VARIABLES:                        This data set contains 5 HDF scientific data 
                                  sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Longitude	Degrees
	Latitude	Degrees
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	Counts	Number Points per Average

NOTES ON DATA:                   Dimension lengths show above may vary between 
                                 files due to variations in the amount of data 
                                 collected per flight track.

                                 Grids are referenced on 5 degree boxes starting 
                                 in the lower left corner.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Sample data from the srl25x5_0930_03_hdf file:
This is from the report file for the srl25x5_0930_03_hdf file.
*************************** LONGITUDE NO. 1 ******************************


Longitude:
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00        -180.00        -180.00
        -180.00        -180.00        -180.00

Latitude:
          65.00          60.00          55.00          50.00          45.00
          40.00          35.00          30.00          25.00          20.00
          15.00          10.00           5.00           0.00          -5.00
         -10.00         -15.00         -20.00         -25.00         -30.00
         -35.00         -40.00         -45.00         -50.00         -55.00
         -60.00         -65.00         -70.00

CO:
        -777.77           0.00          95.37          92.63          93.51
          99.57           0.00         125.65           0.00           0.00
           0.00           0.00           0.00          57.35          68.50
           0.00           0.00         106.21         105.84           0.00
         125.89          83.71          90.69          82.26          88.80
          77.19        -777.77        -777.77

N2O:
        -777.77           0.00         311.54         317.94         309.87
         310.93           0.00         351.55           0.00           0.00
           0.00           0.00           0.00         248.63         282.03
           0.00           0.00         317.88         332.78           0.00
         333.67         303.63         308.20         300.40         307.73
         323.04        -777.77        -777.77

Counts:
        -777.77           0.00         134.00          68.00          41.00
           9.00           0.00           8.00           0.00           0.00
           0.00           0.00           0.00          36.00          21.00
           0.00           0.00          57.00           5.00           0.00
          11.00          88.00          69.00          39.00          69.00
          10.00        -777.77        -777.77

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as a
filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used 
to determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and falls
onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199   
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.4  MAPS_OSTA3_COSEC_HDF Data Set
This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:     Measurement of Air Pollution from Satellites 
                                 (MAPS) Office of Space and Terrestrial 
                                 Applications - 3 (OSTA3) Carbon Monoxide Second 
                                 by Second data in Hierarchical Data Format 
                                 (HDF) (MAPS_OSTA3_COSEC_HDF)

FILE NAMING CONVENTION:          MAPS_OSTA3_COSEC_HDF data set files are prefixed 
                                 with "osta3lv2" to indicate they belong to this 
                                 data set. This is followed by a four digit number
                                 (mmdd) that represents the month and the start 
                                 day the data were collected. The name is then 
                                 followed by an underscore and another two 
                                 digit number that represents the beginning hour 
                                 of the day the data were collected for a 
                                 particular granule. Each granule consists of 6 
                                 hours of data. The name ends with an underscore 
                                 followed by the letters "hdf." These three 
                                 letters inform the user that the data are 
                                 written in HDF.

VARIABLES:                       This data set contains 22 HDF scientific data 
                                 sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TERTYPE	Terrain Type Status
	TERHGHT	Height from Sea Level
	DN500mb	Degrees Kelvin
	DNP500mb	Degrees Kelvin
	ATTITUDE	Attitude Status
	DAYNGT	Day/Night Status
	CDST	Processing Status
	STWD	Instrument Status

NOTES ON DATA:                 Dimension lengths show above may vary between files
                               due to variations in the amount of data collected 
                               per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Sample data from the osta3lvl2_1006_00_hdf file:
This is from the report file for the osta3lvl2_1006_00 file.
*************************** LONGITUDE NO. 1 ******************************

Day:
      280.00000      280.00000      280.00000      280.00000      280.00000
      280.00000      280.00000      280.00000      280.00000      280.00000
      280.00000      280.00000      280.00000      280.00000      280.00000
      .... 
Time:
        0.00000        1.00000        2.00000        3.00000        4.00000
        5.00000        6.00000        7.00000        8.00000        9.00000
       10.00000       11.00000       12.00000       13.00000       14.00000
      ...
Latitude:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
Longitude:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
V CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
DV CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
    ...
DVP CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
N:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DN:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DNP:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
CO:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
N2O:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB1:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB2:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TERTYPE:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TERHGHT:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DN500mb:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DNP500mb:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
ATTITUDE:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DAYNGT:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
CDST:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
STWD:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as a
filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used 
to determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.5  MAPS_SRL1_COSEC_HDF Data Set
This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:      Measurement of Air Pollution from Satellites 
                                  (MAPS) Space Radar Laboratory - 1 (SRL1) Carbon 
                                  Monoxide Second by Second Data in Hierarchical 
                                  Data Format (HDF) (MAPS_SRL1_COSEC_HDF)

FILE NAMING CONVENTION:           MAPS_SRL1_COSEC_HDF data set files are prefixed 
                                  with "srl1lv2" to indicate they belong to this 
                                  data set. This is followed by a four digit 
                                  number (mmdd) that represents the month and the 
                                  start day the data were collected. The name is 
                                  then followed by an underscore and another two 
                                  digit number that represents the beginning hour 
                                  of the day the data were collected for a 
                                  particular granule. Each granule consists of 6 
                                  hours of data. The name ends with an underscore 
                                  followed by the letters "hdf." These three 
                                  letters inform the user that the data are 
                                  written in HDF.

VARIABLES:                        This data set contains 22 HDF scientific data 
                                  sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TERTYPE	Terrain Type Status
	TERHGHT	Height from Sea Level
	DN500mb	Degrees Kelvin
	DNP500mb	Degrees Kelvin
	ATTITUDE	Attitude Status
	DAYNGT	Day/Night Status
	CDST	Processing Status
	STWD	Instrument Status

NOTES ON DATA:                   Dimension lengths show above may vary between 
                                 files due to variations in the amount of data 
                                 collected per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Please refer to the sample record above. (osta3lvl2_1006_00_hdf)

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts 
as a filter for the effects of CO present in the middle troposphere. A second 
beam falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of 
N2O present in the atmosphere. The global distribution of N2O is well known, so 
the N2O signal can be used to detect the presence of clouds in the field of view 
and to correct the simultaneous CO measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov


INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view 
and to correct the simultaneous CO measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.6  MAPS_SRL2_COSEC_HDF Data Set
This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:        Measurement of Air Pollution from Satellites
                                    (MAPS) Space Radar Laboratory - 2 (SRL2) 
                                    Carbon Monoxide Second by Second Data in 
                                    Hierarchical Data Format (HDF) 
                                    (MAPS_SRL2_COSEC_HDF)

FILE NAMING CONVENTION:             MAPS_SRL2_COSEC_HDF data set files are 
                                    prefixed with "srl2lv2" to indicate they 
                                    belong to this data set. This is followed by 
                                    a four digit number (mmdd) that represents the
                                    month and the start day the data were 
                                    collected. The name is then followed by an 
                                    underscore and another two digit number that 
                                    represents the beginning hour of the day the 
                                    data were collected for a particular granule. 
                                    Each granule consists of 6 hours of data. The 
                                    name ends with an underscore followed by the 
                                    letters "hdf." These three letters inform the 
                                    user that the data are written in HDF.

VARIABLES:                          This data set contains 22 HDF scientific data 
                                    sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	CO	Parts Per Billion by Volume
	N2O	Parts Per Billion by Volume
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TERTYPE	Terrain Type Status
	TERHGHT	Height from Sea Level
	DN500mb	Degrees Kelvin
	DNP500mb	Degrees Kelvin
	ATTITUDE	Attitude Status
	DAYNGT	Day/Night Status
	CDST	Processing Status
	STWD	Instrument Status

NOTES ON DATA:                    Dimension lengths show above may vary between 
                                  files due to variations in the amount of data 
                                  collected per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Please refer to the sample record above. (osta3lvl2_1006_00_hdf)

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.

CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov


INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of 
N2O present in the atmosphere. The global distribution of N2O is well known, so 
the N2O signal can be used to detect the presence of clouds in the field of 
view and to correct the simultaneous CO measurement for systematic errors in the 
data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.7  MAPS_OSTA3_LVL1_HDF Data Set

This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:         Measurement of Air Pollution from Satellites 
                                     (MAPS) Office of Space and Terrestrial 
                                     Applications - 3 (OSTA3) Level 1 Data in 
                                     Hierarchical Data Format (HDF) 
                                     (MAPS_OSTA3_LVL1_HDF)

FILE NAMING CONVENTION:              MAPS_OSTA3_LVL1_HDF data set files are 
                                     prefixed with "osta3lv1" to indicate they 
                                     belong to this data set. This is followed by 
                                     a four digit number (mmdd) that represents 
                                     the month and the start day the data were 
                                     collected. The name is then followed by an 
                                     underscore and another two digit number that 
                                     represents the beginning hour of the day the 
                                     data were collected for a particular granule.
                                     Each granule consists of 6 hours of data. The
                                     name ends with an underscore followed by the 
                                     letters "hdf." These three letters inform the
                                     user that the data are written in HDF.

VARIABLES:                           This data set contains 27 HDF scientific data
                                     sets (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TBB3	Degree Kelvin
	TBB4	Degree Kelvin
	TBB5	Degree Kelvin
	TBB6	Degree Kelvin
	TREF	Degree Kelvin
	TBasePlate	Degree Kelvin
	TCELL1	Degree Kelvin
	TCELL2	Degree Kelvin
	TDET1	Degree Kelvin
	TDET2	Degree Kelvin
	TDET3	Degree Kelvin
	REF5V		Voltage
	RV		Voltage
	STWD	Whole number
	CB	Whole number: 0 or 1

NOTES ON DATA:                      Dimension lengths show above may vary between 
                                    files due to variations in the amount of data 
                                    collected per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Sample data from the osta3lvl1_1006_00_hdf file:
This is from the report file for the osta3lv1_1006_00 file.
*************************** LONGITUDE NO. 1 ******************************

Day:
      280.00000      280.00000      280.00000      280.00000      280.00000
      280.00000      280.00000      280.00000      280.00000      280.00000
      280.00000      280.00000      280.00000      280.00000      280.00000
      .... 
Time:
        0.00000        1.00000        2.00000        3.00000        4.00000
        5.00000        6.00000        7.00000        8.00000        9.00000
       10.00000       11.00000       12.00000       13.00000       14.00000
      ...
Latitude:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
Longitude:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
V CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
DV CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
    ...
DVP CHANNEL:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
N:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DN:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
DNP:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB1:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB2:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB3:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB4:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB5:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBB6:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TREF:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TBasePlate:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TCELL1:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TCELL2:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TDET1:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TDET2:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
TDET3:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
REF5V:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
RV:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
STWD:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...
CB:
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     -777.77000     -777.77000     -777.77000     -777.77000     -777.77000
     ...

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and falls
onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.8  MAPS_SRL1_LVL1_HDF Data Set

This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:         Measurement of Air Pollution from Satellites 
                                     (MAPS) Space Radar Laboratory - 1 (SRL1) 
                                     Level 1 Data in Hierarchical Data Format 
                                     (HDF) (MAPS_SRL1_LVL1_HDF)

FILE NAMING CONVENTION:                 MAPS_SRL1_LVL1_HDF data set files are 
                                        prefixed with "srl1lv1" to indicate they 
                                        belong to this data set. This is followed 
                                        by a four digit number (mmdd) that 
                                        represents the month and the start day the
                                        data were collected. The name is then 
                                        followed by an underscore and another two 
                                        digit number that represents the beginning
                                        hour of the day the data were collected 
                                        for a particular granule. Each granule 
                                        consists of 6 hours of data. The name ends
                                        with an underscore followed by the letters
                                        "hdf." These three letters inform the user
                                        that the data are written in HDF.

VARIABLES:                              This data set contains 27 HDF scientific 
                                        data sets (i.e., variables) per data file.
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TBB3	Degree Kelvin
	TBB4	Degree Kelvin
	TBB5	Degree Kelvin
	TBB6	Degree Kelvin
	TREF	Degree Kelvin
	TBasePlate	Degree Kelvin
	TCELL1	Degree Kelvin
	TCELL2	Degree Kelvin
	TDET1	Degree Kelvin
	TDET2	Degree Kelvin
	TDET3	Degree Kelvin
	REF5V		Voltage
	RV		Voltage
	STWD	Whole number
	CB	Whole number: 0 or 1

NOTES ON DATA:                     Dimension lengths show above may vary between 
                                   files due to variations in the amount of data 
                                   collected per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Please refer to the sample record above. (osta3lv1_1006_00_hdf)

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and falls
onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and falls
onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov

5.9  MAPS_SRL2_LVL1_HDF Data Set

This data set is written in NCSA's HDF format. The data files are organized by 
date.

LONG NAME FOR THIS DATA SET:   Measurement of Air Pollution from Satellites (MAPS)
                               Space Radar Laboratory - 2 (SRL2) Level 1 Data in 
                               Hierarchical Data Format (HDF) (MAPS_SRL2_LVL1_HDF)

FILE NAMING CONVENTION:        MAPS_SRL2_LVL1_HDF data set files are prefixed 
                               with "srl2lv1" to indicate they belong to this data
                               set. This is followed by a four digit number (mmdd)
                               that represents the month and the start day the 
                               data were collected. The name is then followed by 
                               an underscore and another two digit number that 
                               represents the beginning hour of the day the data 
                               were collected for a particular granule. Each 
                               granule consists of 6 hours of data. The name ends 
                               with an underscore followed by the letters "hdf." 
                               These three letters inform the user that the data 
                               are written in HDF.

VARIABLES:                     This data set contains 27 HDF scientific data sets 
                               (i.e., variables) per data file. 
The variable names are:
	Variable	Units
	Day	Julian Day
	Time	GMT in Seconds
	Latitude	Degrees
	Longitude	Degrees
	V CHANNEL	Voltage
	DV CHANNEL	Voltage
	DVP CHANNEL	Voltage
	N	Radiance (w/cm2/steradian)
	DN	Radiance (w/cm2/steradian)
	DNP	Radiance (w/cm2/steradian)
	TBB1	Degree Kelvin
	TBB2	Degree Kelvin
	TBB3	Degree Kelvin
	TBB4	Degree Kelvin
	TBB5	Degree Kelvin
	TBB6	Degree Kelvin
	TREF	Degree Kelvin
	TBasePlate	Degree Kelvin
	TCELL1	Degree Kelvin
	TCELL2	Degree Kelvin
	TDET1	Degree Kelvin
	TDET2	Degree Kelvin
	TDET3	Degree Kelvin
	REF5V		Voltage
	RV		Voltage
	STWD	Whole number
	CB	Whole number: 0 or 1

NOTES ON DATA:                 Dimension lengths show above may vary between files
                               due to variations in the amount of data collected 
                               per flight track.

FIRST RECORD OF DATA FROM FIRST DATA GRANULE:
Please refer to the sample record above. (osta3lv1_1006_00_hdf)

INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and 
falls onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov


INSTRUMENTATION:
The MAPS instrument is based on a technique called gas filter radiometry. Thermal 
energy from the Earth passes through the atmosphere and enters the viewport of the
downlooking MAPS instrument. Carbon monoxide and nitrous oxide (N2O) in the 
atmosphere produce unique absorption lines in the transmitted energy. The energy 
which enters the MAPS instrument is split into three beams. One beam passes 
through a cell containing CO and falls onto a detector. This CO gas cell acts as 
a filter for the effects of CO present in the middle troposphere. A second beam 
falls directly onto a detector without passing through any gas filter. The 
difference in the voltage of the signals from these two detectors can be used to 
determine the amount of CO present in the atmosphere at an altitude of 7-8 km. 
A third beam of the incident energy passes through a cell containing N2O and falls
onto a detector. This N2O gas cell acts as a filter for the effects of N2O 
present in the atmosphere. The global distribution of N2O is well known, so the 
N2O signal can be used to detect the presence of clouds in the field of view and 
to correct the simultaneous CO measurement for systematic errors in the data.
CONTACT FOR DATA PRODUCT INFORMATION:
Dr. Vickie S. Connors 
NASA LaRC, Atmospheric Sciences Division
Mail Stop 401A
Hampton, VA 23681-2199
U.S.A.

Tel: (757) 864-5849
E-mail: v.s.connors@larc.nasa.gov


6.0  Implementation Notes
Section 6.0 gives the user a brief explanation on how to run the sample read 
software.

6.1  MAPS CO5X5 Read Program

There is only one version of the read program available for these data set 
(MAPS_OSTA3_CO5X5_HDF, MAPS_SRL1_CO5X5_HDF, and MAPS_SRL2_CO5X5_HDF). 
The following represents a sample execution of the C program, maps_co5x5_read.c.

sorcerer% read_maps_co5x5
   *****************************************************
   *                                                   *
   *      MAPS Read Program Version 2.0                *
   *                                                   *
   *                                                   *
   * This sample read program currently reads the      *
   * following data sets:                              *
   *                                                   *
   *                  MAPS_SRL1_CO5x5_HDF              *
   *                  MAPS_SRL2_CO5x5_HDF              *
   *                  MAPS_OSTA3_CO5x5_HDF             *
   *                                                   *
   *                                                   *
   *                   02-02-1999                      *
   *****************************************************

Enter the input data file name. This code assumes file is in your current
working directory.
srl15x5_0409_09_hdf


In your output report file, do you want to include the 
file description? Enter 1 for yes and 2 for no.... 1


Would you like to have the program write out all of the
parameters? Enter Y for yes or N for no. --> y

Reading labels....


There are 72 records/number of events in the HDF file.
NOTE: This will take some time to write out the report file.


Reading data, Please wait...


         ... and wait...
 
 
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@                                                             @
@ This program has completed and has created an output report @
@ file called./srl15x5_0409_09_hdf.rpt in your current        @
@ working directory.                                          @
@                                                             @
@                                                             @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@




6.2  MAPS COSEC Read Program

There is only one version of the read program available for these data set 
(MAPS_OSTA3_COSEC_HDF, MAPS_SRL1_COSEC_HDF, and MAPS_SRL2_COSEC_HDF). 
The following represents a sample execution of the C program, maps_co5x5_read.c.

sorcerer% read_maps_cosec
   *****************************************************
   *                                                   *
   *           MAPS Read Program Version 2.0           *
   *                                                   *
   *                                                   *
   *  This sample read program currently reads the     *
   *  following data sets:                             *
   *                                                   *
   *             MAPS_SRL1_COSEC_HDF                   *
   *             MAPS_SRL2_COSEC_HDF                   *
   *             MAPS_OSTA3_COSEC_HDF                  *
   *                                                   *
   *                                                   *
   *                   02-02-1999                      *
   *****************************************************
 
 
Enter the input data file name.  This code assumes file is in your current
working directory.
osta3lv2_1006_00_hdf
 
 
In your output report file, do you want to include the 
file description?  Enter 1 for yes and 2 for no .... 1
 
 
Would you like to have the program write out all of the
parameters?  Enter Y for yes or N for no.  -->  y
 
 
Reading labels....
 
 
There are 12 records/number of events in the HDF file.
NOTE:  This will take some time to write out the report file.
 
 
Reading data, Please wait ...
Data are printed from left to right in event order.
 
 
 
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@                                                             @
@ This program has completed and has created an output report @
@ file called ./osta3lv2_1006_00_hdf.rpt in your current      @
@ working directory.                                          @
@                                                             @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 


6.3  MAPS COSEC Read Program

There is only one version of the read program available for these data set 
(MAPS_OSTA3_LVL1_HDF, MAPS_SRL1_LVL1_HDF, and MAPS_SRL2_LVL1_HDF). 
The following represents a sample execution of the C program, maps_lvl1_read.c.

sorcerer% read_maps_lvl1

   *****************************************************
   *                                                   *
   *           MAPS Read Program Version 2.0           *
   *                                                   *
   *                                                   *
   *  This sample read program currently reads the     *
   *  following data sets:                             *
   *                                                   *
   *             MAPS_SRL1_LVL1_HDF                    *
   *             MAPS_SRL2_LVL1_HDF                    *
   *             MAPS_OSTA3_LVL1_HDF                   *
   *                                                   *
   *                                                   *
   *                   02-02-1999                      *
   *****************************************************
 
 
 
 
 
Enter the input data file name.  This code assumes file is in your current
working directory.
osta3lv1_1006_00_hdf
 
 
In your output report file, do you want to include the 
file description?  Enter 1 for yes and 2 for no .... 2
 
 
y
Would you like to have the program write out all of the
parameters?  Enter Y for yes or N for no.  -->  
 
Reading labels....
 
 
There are 12 records/number of events in the HDF file.
NOTE:  This will take some time to write out the report file.
 
 
Reading data, Please wait ...
Data are printed from left to right in event order.
 



@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@                                                             @
@ This program has completed and has created an output report @
@ file called ./osta3lvl1_1006_00_hdf.rpt in your current     @
@ working directory.                                          @
@                                                             @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@




Updated: February 1, 1999           LD_008_015_001_00_00_0_19990201
Last Updated: February 1, 1999      LD_008_015_001_00_00_0_19990201