MODIS2LAS
Software Requirements Specification

April Shimitz
Computer Services Branch
Software Engineering Department

May 21, 2001



Signatures

Prepared by:                                       
April Shimitz
Software Engineer,
Raytheon, ITSS
Concurred by:                                       
Tim Beckmann
Software Project Lead,
Raytheon, ITSS
Approved by:                                       
Charles Larson
Project Manager,
Raytheon, ITSS

Document History

Number Date and Sections Notes
1 May 21, 2001 Document created
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Contents


INTRODUCTION

Identification

MODIS2LAS is a data ingest application that runs under the LAS environment.

Application Overview

MODIS2LAS will ingest a MODIS HDF-EOS or raw binary product and create an image in the LAS format. The application will support 2-D gridded (Level-3) MODIS data products.

Unlike most of the LAS ingest applications, MODIS2LAS will not contain the code that performs the actual image data processing. Instead, it makes use of the MODIS Reprojection Tool (MRT), a product of Raytheon ITSS and the South Dakota School of Mines and Technology, and TRANSLAS, an existing LAS application. The MRT is used to convert the MODIS data product file(s) to a set of binary files, one file for each SDS requested for processing, and an associated header file. TRANSLAS is then used to complete the image processing by converting the flat binary files to a LAS image product. See Scope/Limitations Section for a brief outline of the implementation strategy that will be used for MODIS2LAS.

Document Overview

The purpose of this document is to record the requirements that have been established for MODIS2LAS.

REFERENCED DOCUMENTS

1. MODIS Data Product Descriptions

2. HDF-EOS Standards and Tools Information Center 3. MODIS Reprojection Tool User's Manual

REQUIREMENTS

Interface Requirements

1. Input Parameters

2. Output Parameters

3. Global Parameters

Functional Requirements

4. This application must be able to process all 2-D gridded (Level-3) MODIS data products. Support for higher-dimensional data products and swath (Level-1 and Level-2) data products will be considered once they are supported by the MRT (this is expected to occur around the October, 2001 time frame).

5. This application must be able to process multi-resolution data.

6. This application must be able to process data products that contain SDSs of differing data types.

7. This application will support processing data from disk, CD, and DVD.

8. This application will support processing products containing 8-bit unsigned, 16-bit signed, and 32-bit signed integer data as well as 32-bit float data.

9. If possible, retrieve DDR values from the flat files' header file. Critical field values being unavailable will cause a fatal error.

Operational Requirements

10. All files will be checked for existence and fatal error messages issued when appropriate.

11. Error messages will specify the application name and the extent of the error. They will also comply with the LAS standard.

Other Requirements

12. This application shall run under the LAS environment and on any operating system that is currently supported for the LAS environment.

MODISSDS Requirements

MODISSDS is a support routine for MODIS2LAS that will query the specified MODIS data product and generate a numbered list of the SDSs present. It will classify each SDS as supported or unsupported, providing a short reason why it does not support processing each SDS indicated as such. The intent is that the user run this application prior to running MODIS2LAS to determine the SDSs available for processing and to assign each a number by which to specify it for ingest in the BANDS parameter of MODIS2LAS.

MODISSDS Interface Requirements

13. Input Parameters

Functional Requirements

14. MODISSDS will print the following information regarding the SDSs present in the specified MODIS data product:

SCOPE/LIMITATIONS

  1. Prior to running MODIS2LAS, the user should run MODISSDS, passing it the file they wish to ingest. MODISSDS will query the data product specified to determine and report the SDSs available for processing. See the MODISSDS Requirements.

  2. The general implementation strategy for MODIS2LAS will be to use the MRT to convert the MODIS data product to flat files, which will then be ingested to LAS by TRANSLAS. The DDR files will then be updated using the information from the header file created by the MRT. Intermediate files will be removed at this point, leaving the user with the output LAS image file(s). The output product will be in the Integerized Sinusoidal map projection.

    There will be a number of intermediate files created by the MRT, including a log file generated by the MRT, a header file, and a data file for each SDS being processed. The flat files will need to be grouped for ingest by TRANSLAS according to common resolution and data type.

  3. The MODIS instrument contains 36 spectral bands at three different spatial resolutions at nadir of 250 meters for bands 1-2, 500 meters for bands 3-7, and 1000 meters for bands 8-36. MODIS Level 3 data products available will vary by resolution (250m - 1000m) and the number of bands included. Refer to Referenced Document 1 for detailed descriptions of the SDSs in each product.

ACRONYMS

DAAC Distributed Active Archive Center
EDC EROS Data Center
HDF-EOS Hierarchical Data Format-Earth Observing System (a specialized form of NCSA's HDF format)
LAS Land Analysis System
MODIS Moderate-Resolution Imaging Spectroradiometer
MRT MODIS Reprojection Tool
NCSA The National Center for Supercomputing Applications
SDS Scientific Data Set
TAE Transportable Applications Environment