Documentation for Data Products
Southeast Asia

Data description:

Pathfinder data from the 90’s epoch is derived from Landsat Thematic Mapper (TM) data.  Data from the 80’s and 70's epoch is from Landsat Multi Spectral Scanner (MSS).  Spatial accuracy is 500 m for the TM and 1000 m for the MSS.  Adjacent edged of these products are not matched.  6 data values exist in the data set:

Data Value  Description
1: Forest
2: Nonforest
4: Water
5: Cloud
6: Cloud Shadow

The data is distributed in 180km x 180km tiles equivalent to the World Reference System paths and rows.  Data coordinates are Universal Transverse Mercator meters.

File format:

The data file and accompanying projection file is ASCII format.  The data file is compressed with UNIX compress.  Use UNIX uncompress to decompress the data file.  For PC users software is available on the Winzip World Wide Web home page to decompress UNIX compress files.  When uncompressed the data file size will exceed 100 Megabytes.

The data and projection files are created with the Arc/Info Geographic Information System (gis) software.  After decompression it can be ingested into Arc/Info using the command ASCIIGRID.

The data file consists of header information containing a set of keywords, followed by cell values in row-major order.  The file format is:

NCOLS xxx
NROWS
XLLCORNER xxx
YLLCORNER xxx
CELLSIZE xxx
NODATA _VALUE xxx
Row 1
Row 2
   :
   :
row n

xxx is a number and NODATA is a fill value.
The end of each row of data from the grid is terminated with a carriage return in the file.

Example from 1992 TM analysis:

NCOLS 7633
NROWS 6688
XLLCORNER 228200.395
YLLCORNER 9262894
CELLSIZE 28.8
NODATA_value –9999
-9999 –9999 –9999 –9999 –9999 –9999 –9999 –9999 1 1 1 2 2 1 1 1 3 4 4 17
-9999 –9999 –9999 –9999 –9999 –9999 –9999 –9999 1 1 2 2 2 2 1 1 1 4 11 7….