Landsat Surface Reflectance Quality 

Assurance Extraction (Version 1.7)

Techniques and Methods 11–C7

U.S. Department of the Interior

U.S. Geological Survey
Landsat Surface Reflectance Quality 

Assurance Extraction (Version 1.7)

Chapter 7 of

Geographic Information Systems Tools and Applications

Book 11, Collection and Delineation of Spatial Data

Techniques and Methods 11–C7

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2013

Revised and reprinted: 2013

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Jones, J.W., Starbuck, M.J., and Jenkerson, C.B., 2013, Landsat surface reflectance quality assurance extraction (version 1.7): U.S. Geological Survey Techniques and Methods, book 11, chap. C7, 9 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Data Access and Acquisition.......................................................................................................................3

Software Access and Acquisition ..............................................................................................................3

Software Installation and Setup..................................................................................................................3

Running the Command Named “unpack_sds_bits” ................................................................................4

Adding QA Data to ENVI ...............................................................................................................................5

Adding QA Data to ERDAS Imagine............................................................................................................6

Reference Cited..............................................................................................................................................9

Figures

1. Screen capture showing that band names have been edited to reflect their 

content in the “Available Bands List” and the selection of the ENVI “Pixel-Based 

Mosaicking” tool (for compiling files).......................................................................................5

2. Screen capture showing that the files already loaded in ENVI must be imported 

into the mosaicking tool...............................................................................................................5

3. Screen capture showing the display of a cloud mask on top of the other band 

layers as a result of importing in sequence in ENVI...............................................................6

4. Screen capture showing the designation of an output file name and the 

specification of the background value (that is, parameter editing) in ENVI.......................6

5. Screen capture showing the use of the ERDAS “Subset Image” option............................7

6. Screen capture showing the use of the ERDAS “Export” option (see fig. 7) .....................7

7. Screen capture showing how to define the ERDAS output file format ...............................8

8. Screen capture showing the appropriate file type and media parameter to use 

when importing the output of the previous step in ERDAS....................................................8

9. Screen capture showing the selection of BIP and unsigned 1 Bit as the 

parameters to use as part of the processing in ERDAS.........................................................8

10. Screen capture showing the use of ERDAS “ImageInfo” to apply the 

georeferencing information to the resulting image................................................................8

11. Screen capture showing the specification of the spheroid and datum names 

and the Universal Transverse Mercator (UTM) zone number ..............................................9

12. Screen capture showing display of spectral-test-based land/water mask 

(bit 11; layer 5 in ERDAS) .............................................................................................................9

13. Screen capture showing view of the individual bit values for each quality 

assurance (QA) bit........................................................................................................................9

Table

1. Bit descriptions for lndsr.filename.hdf Band 8 named “lndsr.filename.hdf” (quality 

assurance).....................................................................................................................................2
iv

Abbreviations and Acronyms

ACCA Landsat Automated Cloud-Cover Assessment

ASCII American Standard Code for Information Interchange

BIP Band Interleaved by Pixel

CDR climate data record

DOS disk operating system

ECV essential climate variable

ENVI software package for image processing

EOS Earth Observing System

ERDAS software for image processing

EROS USGS Earth Resource Observation and Science Center

ESPA EROS Science Processing Architecture

GIS geographic information system

HDF Hierarchical Data Format

LDOPE Land Data Operational Product Evaluation

LEDAPS Landsat Ecosystem Disturbance Adaptive Processing System

LP DAAC NASA Land Processes Distributed Active Archive Center

LSRP Landsat Surface Reflectance Product

MODIS Moderate Resolution Imaging Spectroradiometer

NASA National Aeronautics and Space Administration

QA quality assurance

SDS Science Data Set

SR surface reflectance

USGS U.S. Geological Survey

UTM Universal Transverse Mercator
Landsat Surface Reflectance Quality Assurance 

Extraction (Version 1.7)

By J.W. Jones,1 M.J. Starbuck,2 and C.B. Jenkerson3

Abstract

The U.S. Geological Survey (USGS) Land Remote Sensing Program is developing an operational capability to produce 

Climate Data Records (CDRs) and Essential Climate Variables 

(ECVs) from the Landsat Archive to support a wide variety of 

science and resource management activities from regional to 

global scale. The USGS Earth Resources Observation and Science (EROS) Center is charged with prototyping systems and 

software to generate these high-level data products. Various 

USGS Geographic Science Centers are charged with particular 

ECV algorithm development and (or) selection as well as the 

evaluation and application demonstration of various USGS 

CDRs and ECVs. Because it is a foundation for many other 

ECVs, the first CDR in development is the Landsat Surface 

Reflectance Product (LSRP). The LSRP incorporates data 

quality information in a bit-packed structure that is not readily 

accessible without postprocessing services performed by the 

user. This document describes two general methods of LSRP 

quality-data extraction for use in image processing systems. 

Helpful hints for the installation and use of software originally developed for manipulation of Hierarchical Data Format 

(HDF) produced through the National Aeronautics and Space 

Administration (NASA) Earth Observing System are first provided for users who wish to extract quality data into separate 

HDF files. Next, steps follow to incorporate these extracted 

data into an image processing system. Finally, an alternative 

example is illustrated in which the data are extracted within a 

particular image processing system.

Introduction

The U.S. Geological Survey (USGS) Land Remote Sensing Program is developing capabilities to produce climate 

data records (CDRs) and essential climate variables (ECVs) 

to support a broad range of environmental, resource management, and hazard mitigation activities up to international 

levels. The USGS Earth Resources Observation and Science 

Center (EROS) has developed a production system prototype 

called the EROS Science Processing Architecture (ESPA) to 

integrate CDR and ECV algorithms. The first CDR is “surface reflectance” produced from Landsat and is referred to 

as “Landsat Surface Reflectance Product” (or LSRP). The 

LSRP production process is based on Landsat Ecosystem 

Disturbance Adaptive Processing System (LEDAPS) software 

(Masek and others, 2006) and includes surface reflectance 

values calculated on demand for the Landsat Archive from 

1984 to present, as well as associated quality assurance (QA) 

data. These products are distributed in the hierarchical data 

format (HDF) used for many publicly available remote sensing 

products, notably the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) collections 

from the Moderate Resolution Imaging Spectroradiometer 

(MODIS) instruments aboard the Terra and Aqua platforms. 

Many public and commercial software packages are capable 

of reading HDF files, and the Landsat reflectance data are 

easily accessible with existing tools. However, the QA data 

are “packed” using binary encoding that often proves difficult to extract and use within the context of image processing 

and geographic information system (GIS) software packages. 

Additional processing is required from the users to effectively 

apply QA information to the science data.

Note that the ESPA currently produces two different 

types of Landsat products: exoatmospheric (top of the atmosphere) radiance and surface reflectance (the file names begin 

with “lndcal” and “lndsr,” respectively). Both of these products contain QA information that can be unpacked using the 

technique described here. However, no specifics on the content 

and manipulation of the radiance files are provided. Rather, 

this tutorial is focused specifically on the manipulation of the 

surface reflectance (lndsr) product.

The QA definitions for LSRP are written to Band 8 

named “lndsr_QA” (beginning with an “l” as in “landsat”), 

and a legend for interpretation of their unpacked values is 

shown in table 1.

A set of software tools to manipulate MODIS data was 

developed by the Land Data Operational Product Evaluation 

(LDOPE) team and are distributed at no cost from the NASA 

1

 U.S. Geological Survey, Reston, Va.

2

 U.S. Geological Survey, Rolla, Mo.

3

 Earth Resources Technololgy, Inc., Laurel, Md.
2 Landsat Surface Reflectance

Table 1. Bit descriptions for lndsr.filename.hdf Band 8 named “lndsr.filename.hdf” (quality assurance). Bit patterns are read from 

right to left (that is, bit 0 = least significant bit, and bit 15 = most significant bit). Bits can be extracted using the command named 

“unpack_sds_bits” in the Land Data Operational Product Evaluation toolbox.

Bit no. Parameter name Value Interpretation 

0 Unused 

0 --- 

1 --- 

1 Valid data 

0 yes 

1 no 

2 ACCA-based cloud mask 

0 clear 

1 cloudy 

3 Unused 

0 --- 

1 --- 

4 ACCA-based snow mask

0 snow absent

1 snow present 

5 DEM-based land/water mask 

0 water 

1 land 

6 Dense dark vegetation (DDV) 

0 DDV absent 

1 DDV present 

7 Unused 

0 --- 

1 --- 

8 Surface reflectance-based cloud 

mask 

0 clear 

1 cloudy 

9 Cloud shadow mask 

0 cloud shadow absent 

1 cloud shadow present 

10 Surface reflectance-based snow 

mask 

0 snow absent 

1 snow present 

11 Spectral test-based land/water 

mask 

0 water 

1 land 

12 Adjacent cloud 

0 adjacent cloud absent 

1 adjacent cloud present 

13 Unused 

0 --- 

1 --- 

14 Unused 

0 --- 

1 --- 

15 Unused 

0 --- 

1 --- 

Land Processes Distributed Active Archive Center (LP DAAC; 

https://lpdaac.usgs.gov/tools/ldope_tools). The LDOPE 

Toolbox includes command line software to deconstruct 

bit-packed data layers. Because of their production heritage 

(LEDAPS applies MODIS-based algorithms to Landsat data), 

LDOPE tools are able to unpack the QA information in LSRP. 

This report details a procedure for acquiring, downloading, 

and installing the “runtime” version of the LDOPE Toolbox 

on the Windows operating system so that all LDOPE tools 

can be accessed. Next, the report focuses specifically on how 

the LDOPE tool named “unpack_sds_bits.exe” can be used 

to extract QA information from LSRP files. Finally, because 

some issues may be encountered when importing LDOPE 

outputs into common image processing packages, the report 

provides tested procedures that allow QA data to be appropriately registered with other CDR data, displayed, and used 

effectively in either the ENVI or ERDAS Imagine commercial 

image processing systems.
Software Installation and Setup 3

Data Access and Acquisition

The currently provisional LSRP data collections 

are accessible through a nominal user interface hosted at 

http://landsat.usgs.gov/PLSRP.php, which provides general 

product characteristics and a link to the ordering system. Users 

must submit a list of the Landsat scenes desired for surface 

reflectance processing in text format, as well as an electronic 

mail address for notification of order status and completion. A 

USGS-supplied user name and password is required to request 

and retrieve data products. To request account information, 

complete the “Contact Us” form on the LSRP Web site, selecting the topic named “Surface Reflectance Data Request.”

Software Access and Acquisition

The LDOPE Toolbox is provided at no cost to the user 

through the NASA Land Processes Distributed Active Archive 

Center (LP DAAC) operated at USGS EROS. The user must 

establish a username and password (at “Sign Up”) before 

the software can be downloaded. Both the account establishment and download can be accomplished from this URL: 

https://lpdaac.usgs.gov/tools/ldope_tools.

Software Installation and Setup

The assumption is made that the necessary user account 

has been established, and that the zip file named “LDOPE_

Win_bin.zip” has been downloaded to the user’s local Windows desktop computer. It is also assumed that uncompression 

software, such as WinZip, is available on the desktop. Note:

Administrator rights may be required to fully accomplish 

step 3.

Note as well that the following instructions are an adaptation and expansion of the procedures described in appendix D 

of the LDOPE_Users_Manual.pdf file:

1. Make the directory where the software will be installed 

and operated. For example, create a directory called 

“ESPA_QA” on the C drive.

2. Unzip the file named “LDOPE_Win_bin” and place the 

subdirectories it contains into the directory created above.

Those subdirectories are named “bin” and “ANCILLARY.” The bin subdirectory contains the executables and the 

ANCILLARY subdirectory contains numerous files used in 

map projection and georeferencing. Given the current example, a directory structure similar to that shown below should 

be present on the local disk:

C:\ESPA_QA

C:\ESPA_QA\ANCILLARY

C:\ESPA_QA\Bin

3. Create a new environment variable named “$ANCPATH“ 

(Windows XP shown first, followed by Windows 7 steps).

This variable will point to the location of the ancillary 

files in the new directory with subdirectories of LDOPE_Win_

bin/ANCILLARY. To accomplish this in Windows XP, follow 

the steps below:

A. Click the Windows “start” button.

B. Select the control panel.

C. Click on the “systems” icon.

D. In the systems window, select the advanced tab.

E. In the advance window, select the button labeled 

”Environment Variables.”

F. In the panel labeled ”User variable for username,” 

click on the button labeled “New.”

G. For the box labeled ”Variable name:,” enter the name 

“ANCPATH.”

H. For the box labeled ”Variable value:,” enter the 

value named “yourchoice/ANCILLARY” where 

”yourchoice” is the directory created to hold the 

ANCILLARY and bin directories. In the case of 

the current example, “yourchoice” would be named 

“ESPA_QA” and the complete environment path 

would be “ESPA_QA/ANCILLARY.” (Note: The 

forward slash “/” is used.)

I. To avoid having to stipulate the path to the executable command each time it is run, add the path to 

the bin directory (that is, “yourchoice/bin”) to the 

environment variable named “$path.” Instructions 

for this process (for most operating systems) can be 

found here: http://java.com/en/download/help/path.

xml. If this path is not configured, input files must be 

copied to the directory named “yourchoice/LDOPE_

Win_bin” or the path to the command (for example, 

“yourchoice/LDOPE_Win_bin/”) must be specified 

from within the directory where the input data are 

found and output data will be placed. This latter case 

(specifying the path to the executable) is used in the 

example in step 4 below.

To create a new environment variable in Windows 7, follow the steps below:

A. Click the Windows “start” button.

B. Select the control panel.

C. Click on the “system” icon.

D. In the systems window, select “advanced systems 

settings.”
4 Landsat Surface Reflectance

E. In the window that pops open, select the tab named 

“Advanced.”

F. Click on the button labeled “Environment Variables...”

G. In the panel labeled ”User variable for username,” 

click on the button named “New.”

H. For the box labeled “Variable name:,” enter “ANCPATH.”

I. For the box labeled ”Variable value:,” enter “yourchoice/ANCILLARY” where “yourchoice” is the 

directory created to hold the ANCILLARY and 

bin directories. In the case of the current example, 

“yourchoice” would be “ESPA_QA” and the 

complete environment path would be “ESPA_QA/

ANCILLARY.” (Note: The forward slash “/” is 

used.)

J. To avoid having to stipulate the path to the executable command each time it is run, add the path to 

the bin directory (that is, “yourchoice/bin”) to the 

“$path” environment variable. Instructions for this 

process (for most operating systems) can be found 

here: http://java.com/en/download/help/path.xml. If 

this path is not configured, input files must be copied 

to the “yourchoice/LDOPE_Win_bin” directory or 

the path to the command (for example, “yourchoice/

LDOPE_Win_bin/”) must be specified from within 

the directory where the input data are found and 

output data will be placed. This latter case (specifying the path to the executable) is used in the example 

in step 4 below.

4. Modify the command prompt “windowsize” to properly 

display LDOPE tool instructions and outputs in either XP 

or Windows 7.

The LDOPE commands were written to run on an operating system that uses a wider “screen” than the 80-character 

one provided by default for the disk operating system (DOS) 

command prompt in current Windows operating systems. This 

results in difficult-to-read formatting for help and processing 

messages. To overcome this, the size of the command prompt 

window can be changed to make LDOPE help and output 

easier to read, using the following steps:

A. Open a command prompt window by either clicking 

on “start/run,” typing “cmd,” and clicking on “OK,” 

or at the “start/programs/accessories/command” 

prompt.

B. Click on the “c:\” icon in the upper left corner of the 

command prompt window that just opened.

C. Select “properties.”

D. Select “layout.”

E. Increase the screen buffer size to a width of 100.

F. Increase the window size to a width of 100.

G. Select “OK.”

H. Note: If using Windows XP, the prompt named 

“Save properties for future windows with the same 

title” must be toggled on before clicking “OK” if 

you want to retain the new command window size 

for all subsequent times it is used; otherwise just 

click “OK.”

Running the Command Named 

“unpack_sds_bits”

The “unpack_sds_bits” tool decodes the requested bit 

fields in the input file and writes them to an output HDF file 

for further processing. As per the documentation found at 

http://landsat.usgs.gov/PLSRP.php, each bit is coded with 

“1” or “0” (“yes” or “no,” respectively) values for various 

quality themes such as land, water, clouds, cloud shadow, 

and so forth. In the current example, this tool is being applied 

specifically to unpack two bit fields containing information 

on potential cloud and cloud shadow locations. The cloud 

masks produced through the Landsat Automated Cloud-Cover 

Assessment (ACCA) method and the cloud shadow mask are 

flagged in bits 2 and 9, respectively.

A. Use the existing or open a command window (“start/

all programs/accessories/command” prompt or start/

run and type “cmd”).

B. At the command prompt in the window, change 

directories to the location of the input data. For 

example, if LSRP data are in a directory called 

“testdata,” the following command would be issued: 

cd c:\testdata.

C. Unless the path to the bin subdirectory was added 

to the system path, it must be included when issuing 

each LDOPE tool command. For example, from 

within the testdata directory on the “C” partition a 

command is run to test that environment variables 

were properly set (steps 2G and 2H above), and to 

see what options are possible for the unpack_sds_

bits command. In the current example, the LDOPE 

Toolbox was unzipped in the directory path named 

“ESPA_QA.” Therefore, at the command prompt, 

the following command is issued: 

C:\ESPA_QA\bin\unpack_sds_bits –h.

This will display a page listing of options—inputs 

and outputs associated with the command (more easily read if the command window width was modified 

as instructed in the previous section).
Adding QA Data to ENVI 5

D. Note that for LSRP data, the QA information is 

packed in the Science Data Set (SDS) or “band” that 

is named “lndsr_QA” (beginning with an “l” as in 

“landsat”).

E. For this example, the input LSRP file with a name of 

“lndsr.L5019037_03720010705.hdf” was collected 

via Landsat 5 for path 19 row 37 on July 7, 2001, 

and given an output file name of “2001_07_05_P19_

R37_TM5_clds.hdf.”

The following command string would be issued (all 

on one line) to unpack both the ACCA-based and 

the surface reflectance-based cloud masks, as well 

as the LSRP cloud-shadow mask into the output file, 

assuming the input file is present in the directory 

named “ldope_win_bin\bin”: 

c:\ESPA_QA\ldope_win_bin\bin\unpack_sds_bits 

–sds=lndsr_QA –bit=2,8,9 –of=2001_07_05_P19_

R37_TM7_clds.hdf lndsr.L5019037_03720010705.

hdf

The result is an output HDF file (named “2001_07_05_

P19_R37_TM5_clds.hdf”) with three SDS, or bands, of data: 

the two-cloud and the cloud-shadow masks. This can be read 

by some software packages (for example, ENVI) as a threeband HDF file that will have a value of “1” in the first band for 

every pixel labeled as “cloud” by the ACCA algorithm, a value 

of “1” in the second band for every pixel labeled as “cloud” 

by the surface reflectance-based algorithm, and a value of “1” 

in the third band for every pixel labeled as cloud shadow by 

LSRP processing. The unpack_sds_bits command can be used 

to similarly unpack any other QA bit (for example, bit 10 surface reflectance-based snow mask, bit 11 spectral-test-based 

land/water mask, and so forth) simply by changing the options 

provided for the “-bit” parameter. Additional bits can be added 

and separated by commas. For example, the option string–—

bits=2,9,10—would result in a three-band output file in which 

the third band includes a “1” for every pixel labeled as “snow 

present” by LSRP processing.

Adding QA Data to ENVI

At the time this report was created, georeferencing information embedded in the HDF file produced by the unpack_

sds_bits command is not interpreted when the file is read as 

an HDF by the ENVI image processing system. That is, while 

the binary data can be read and displayed, their georeferencing 

information is “lost.”

Caution: While a LDOPE executable tool (named 

“cp_proj_param”) is designed to embed georeferencing 

information in the HDF file created by the unpack_sds_bits 

tool, it only operates properly in the case of MODIS HDF files 

and should not be used to overcome the problem of missing 

georeferencing in the QA extractions imported to ENVI. However, the output of the unpack_sds_bits tool can be combined 

through ENVI commands with the LSRP reflectance bands so 

that they assume the georeferencing of the other layers and are 

properly and spatially aligned with those other layers.

1. Load both the original ESPA HDF file and the file output 

from the unpack_sds_bits command into ENVI. In the 

example below (fig. 1), the surface reflectance (SR) file 

Figure 1. Screen capture showing that band names have been 

edited to reflect their content in the “Available Bands List” and 

the selection of the ENVI “Pixel-Based Mosaicking” tool (for 

compiling files).

Figure 2. Screen capture showing that the files already loaded 

in ENVI must be imported into the mosaicking tool.
6 Landsat Surface Reflectance

Figure 3. Screen capture showing the display of a cloud mask on 

top of the other band layers as a result of importing in sequence 

in ENVI.

has been loaded and its header was edited so that the band 

names indicate the content of each SDS (band) in the 

original file.

2. Use the ENVI “Pixel Based Mosaicking” tool to compile 

the files (fig. 1).

3. Import both files to the mosaicking tool in sequence (for 

example, SR first, cloud-shadow mask second) so that the 

cloud and shadow masks will be appended as the final two 

bands in the output file (figs. 2, 3, and 4).

When complete, either edit the band file names of the 

output or import an ASCII text file containing them; this 

is recommended for repeat or batch processing.

Adding QA Data to ERDAS Imagine

The QA data stored within Band 8 of the Surface Reflectance HDF file can also be accessed using ERDAS Imagine 

software without using the LDOPE utilities. The following 

steps demonstrate the technique using ERDAS Imagine (version 10.1) with the classic interface. Note: When using this 

process, the extracted layers will be in reverse order of 

their listing in the original input file.

1. Subset the QA band out of the Landsat Surface Reflectance HDF file.

Figure 4. Screen capture showing the designation of an output 

file name and the specification of the background value (that is, 

parameter editing) in ENVI.

To isolate the band named “lndsr_QA” from and LSRP 

file in ERDAS Imagine, begin from the top level DataPrep menu. Using the “Subset Image” option, select the 

LSRP HDF file as input, specify an output file (Imagine 

file format), and choose only Band 8 in “Select Layers” 

(fig. 5).

2. Export the QA subset file to generic binary.

From the top level “Import” menu, click the “Export” 

option. Choose “Generic Binary” in the “Type” dropdown 

menu to define the output file format. Select the LSRP 

Band 8 (QA subset) file created in step 1 as input, and 

specify an output filename (fig. 6).

Default values can be used for the export to Generic 

Binary format.

3. Import the generic binary file back into an ERDAS Imagine file.

Return to the top level “Import” menu, this time specifying the import option. Choose “Generic Binary” from the 

“Type” dropdown to specify file import format. Select the 

binary file created in step 2 as input, and specify an output 

filename (fig. 8).

In the import parameters window, specify Band Interleaved by Pixel (BIP) for “Data Format,” unsigned 1 bit 

for “Data Type,” 16 for the “# Bands,” and enter the number of rows and columns in the image. Row and column 
Adding QA Data to ERDAS Imagine 7

information can be found using ImageInfo on the original 

HDF file (fig. 9).

4. Apply the georeferencing information to the resulting 

image.

Using ImageInfo on the original HDF file, find the coordinate values for the upper left “x” and upper left “y” pixel, 

the pixel size (should be 30 meters in these applications), 

and projection information.

Apply these values to the image created in step 3 using 

ImageInfo edits. First, under the “Edit” tab, select 

“Change Map Model,” and enter the upper left pixel coordinates, pixel size, units, and projection (fig. 10).

Then, under the “Edit” tab again, select “Add/Change 

Projection,” and specify the spheroid and datum names 

and the Universal Transverse Mercator (UTM) zone number (fig. 11).

5. Viewing the QA bit layers.

The QA bit layers can be displayed in ERDAS Imagine 

in several ways. In the example below, the QA layers 

are displayed as a grayscale image with 16 bands, using 

“Raster-Band Combinations” to select which band (QA 

bit) is displayed (fig. 12). In this example, the spectraltest-based land/water mask (bit 11) is displayed (layer 5 in 

ERDAS Imagine).

The individual bit values for each QA bit can be viewed 

simultaneously per pixel using the “Start/Update Inquire 

Cursor” tool in the Viewer (fig. 13). QA bits 0 through 15 

are displayed on separate rows in the cursor window: Layers 1–16 correspond to bits 15–0 (that is, layer 10 displays 

the value for bit 6).

Figure 5. Screen capture showing the use of the ERDAS “Subset 

Image” option.

Figure 6. Screen capture showing the use of the ERDAS 

“Export” option (see fig. 7).
8 Landsat Surface Reflectance

Figure 7. Screen capture showing how to define the ERDAS 

output file format.

Figure 8. Screen capture showing the appropriate file type and 

media parameter to use when importing the output of the previous 

step in ERDAS.

Figure 9. Screen capture showing the selection of BIP and 

unsigned 1 Bit as the parameters to use as part of the processing 

in ERDAS.

Figure 10. Screen capture showing the use of ERDAS 

“ImageInfo” to apply the georeferencing information to the 

resulting image.
Reference Cited 9

Figure 11. Screen capture showing the specification of the 

spheroid and datum names and the Universal Transverse 

Mercator (UTM) zone number.

Figure 12. Screen capture showing display of spectral-testbased land/water mask (bit 11; layer 5 in ERDAS).

Figure 13. Screen capture showing view of the individual bit 

values for each quality assurance (QA) bit.

Reference Cited

Masek, J.G., Vermote, E.F., Saleous, N.E., Wolfe, Robert, 

Hall, F.G., Huemmrich, K.F., Gao, Feng, Kutler, Jonathan, 

and Lim, T.K., 2006, A Landsat surface reflectance dataset 

for North America, 1990–2000: Institute of Electrical and 

Electronics Engineers Geoscience and Remote Sensing Letters, v. 3, no. 1, p. 68–72.
Jones—Landsat Surface Reflectance Quality Assurance Extraction (Version 1.7)—Techniques and Methods 11–C7