# Presentation: 630049

## Introduction to MISR Data Analysis and Tools

**Brian E. Rheingans**
**Jet Propulsion Laboratory, **
**California Institute of Technology**
**Exploring and Using MISR Data**
**Montreal, Quebec, Canada**
**May 2004**

## SOM Background

**The Space Oblique Mercator **
**(SOM) map projection was**
**developed to support LandSat**
**which covers the same**
**large geographic extent as**
**MISR.**
**SOM was designed to minimize**
**the shape distortion and scale**
**errors throughout the length **
**of the MISR swath near the**
**satellite ground track.**
**SOM X is in the direction of the**
**Spacecraft ground track and**
**SOM Y is perpendicular X**

## SOM Background

** ****Terra follows a pattern of orbits which repeats after 233 unique orbits**
** ****Each of the 233 possible orbits is called a path**
** ****SOM defines a separate projection for each of these paths**
** ****For MISR, a path begins at a particular longitude as the satellite**
**  ****crosses the ascending node.**
** ****This path implies a specific longitude of ascending node, which implies**
**   ****a specific SOM projection applicable to that path**

## MISR Orbital Paths/Blocks

## MISR HDF-EOS “Stacked Block” File vs. Aligned Image

- Red Channel Grid SDS (180 Stacked Blocks)

- SOM coordinates of top-block corners part of
- Grid metadata.
- -Projection and orbital parameters part of Grid
- Metadata
- Offsets of each block from the one above is part
- of Stacked-block grid extension metadata.

- Block
- dimension

-  Sample dim / SOM Y

- Line dim / SOM X

- Stacked blocks are due to
- the large geographic extent
- Of the MISR swath

**Standard Product Files**

**Summary Product Files**
**& Browse Product Files**

## MISR HDF-EOS “Stacked Block” Background

**HDF-EOS routines do NOT assemble the**
**Blocks.  That is left for the user.**
**180 blocks are defined for every MISR**
**Product to make block index in absolute.**
**However, roughly 142 blocks have data for**
**Any given orbit.  The extra blocks are to**
**Allow for seasonal variation.**
**We are working on a summary product**
**Specification that will not use the dreaded**
**Stacked blocks, although we will preserve**
**Them for Standard Processing.**

## Where does this pixel belong with the MISR HDF-EOS “Stacked Block” Scheme?

- Inside the HDF-EOS “stacked block grid” = (block, line, sample)
- Convert (block, line, sample) <-> SOM (x,y)
- Requires several metadata values and some arithmetic.
- Convert SOM (x,y) <-> Lat/Lon
- Requires use of GCTP map projection coordinate conversion library in HDF-EOS distribution.
- Units: Integral block, fractional line/sample; meters x/y; decimal degrees Lat/Lon.
- This process is described in the _MISR Data Product Specification_, Appendix A.
- Or simply look up the Lat/Lon of the corresponding block, line, sample in the Ancillary Geographic Product (AGP) datasets (1.1km).

## L1B2 Browse Product

- JPEG format true-color imagery, all 9 cameras, 2.2 km sampling

**Color, multi-angle browse products and on-line interactive viewer available at**
**http://eosweb.larc.nasa.gov/MISRBR/**

**Actual browse resolution**

**Actual browse extent**

## MISR Developed Data visualization and analysis tools

- http://eosweb.larc.nasa.gov/HBDOCS/hdf_data_manipulation.html

## Hdfscan

- • Very useful during the debugging process
- • Displays all HDF-EOS Attributes, SDS’s, Vdata’s easily
- • Allows minor editing of the HDF-EOS file
- • Performs some statistics on the data
- • Does not assemble MISR blocks
- • Written in Fortran 90 and Tcl/tk
-  Only available on SGI Irix and Sun Solaris

## Hdfscan - Locate Path/Block Display using AGP

## MISRView

- • Maps path/orbit to time and date
- • Assembles MISR blocks
- • Reports Lat/Lon using the AGP
- • Displays true color MISR imagery
- • Can reproject MISR imagery
- • Requires IDL

- • Perspective tool
- • Band slider tool
- • Scroll tool
- • Vector overlay tool
- • Reprojection tool
- • Color / Contrast tools

## MISRView – Main Menu

## MISRView – L1B2 imagery

## MISRView – MISR Vision (R-Ba, G-An, B-Bf)

## ERDAS Imagine

- To assist in validating the geo-calibration of MISR data, we wrote custom import routines to convert MISR HDF-EOS “Stacked Block” files into Imagine files preserving geo-location via stored metadata and projection parameters.
- Unfortunately, these are not generally available and are only for SGI Irix.
- The **Summary Product** may supercede the need for these import routines.
- An alternative involves using - **HDF-EOS to GeoTIFF converter (HEG).**
- http://support.erdas.com/downloads/hdf-eos/hef-eos_to_geotiff.asp

## ERDAS Imagine – Full Swath/Full Res. Geo-linked

## ERDAS Imagine – Raster/Vector Overlay

## ERDAS Imagine – GIS Data Analysis

## Level 3 Overview Web Page

- Can view jpegs of all available Level 3 data.
- Can view by product and by month or season.
- Can view animation through a year’s worth of data.
- Can directly download Level 3 HDF files.

-  http://eosweb.larc.nasa.gov/PRODOCS/misr/level3/overview.html

## Level 3 Data File Format

-  Level 3 data files
- In standard HDF-EOS grid format.
- Not in more complicated stack block grid used by Level 1 and Level 2.
- Can be read by any tool that knows HDF-EOS (I.e, IDL).
- To simply view data, use Level 3 web page - no need to work with HDF-EOS file.
- Level 3 HDF-EOS data files can be downloaded directly from the overview web page.

##  What is the Summary Product?

## Tools To View Or Not To View The Summary Product

** **HDFView version 1.3 (free HDF browser, java based, NCSA)
-  Reads generic HDF files.
-  Displays stacked-blocks one block at a time.
-  Display simplified products easily.
-  No geolocation support.
-  Runs out of memory quickly with high resolution data.
-  ENVI verison 4.0 (commercial GIS, IDL-based)
-  Imports HDF data but not HDF-EOS geolocation info.
-  Geolocation parameters can be set manually.
-  ENVI SOM projections agrees with MISR SOM.
-  Does not import HDF fields with more than 3 dimensions**.**

-  Erdas Imagine (version 8.6)
-  Does not support generic HDF or HDF-EOS import.
-  Does support geotiff (see HEG tool).
-  MISRView (version 4.2)
-  Only supports stacked-block files.
-  HDFScan (version 3.5.3)
-  Displays metadata with no problems.
-  Does not display data.  Expects “SOMBlockDim” Dimension.

## HDFView 1.3 - L1B2 Imagery

## ENVI 4.0 - Generic HDF Import

- http://eosweb.larc.nasa.gov/PRODOCS/misr/Quality_Summaries/envi_instructions.html

**Currently the map information**
**needs to be set up manually from the**
**metadata and projection parameters.**
**See above website for instructions.**

## ENVI 4.0 - Selecting Grids and Fields

## MISR L1B2 Imagery in the ENVI Viewer

## North America MISR Multi-path Mosaic

**Albers Conic Equal Area Projection**
**Standard Parallels: 29 ̊ 30 ́ and 45 ̊ 30 ́**
**Projection Center: 36 ̊ N and 92 ̊ W**
**Image credit: NASA/GSFC/LaRC/JPL, MISR Team**
**Multi-path mosaic by Jim Knighton of Clear Light Image Products (jknighton@clear-light.com)**