Accessing the Data for Plate

The downloadable zip files *.zip comprise all the plates from the Cdrom in a 1 or 2 byte binary image format.
The images can be imported into any GIS software (e.g. Arc/Info,Idrisi,Erdas,etc.).

For each image a header file *.hdr, a world file *.blw and an IDRISI32 documentation *.rdc file is given. The former two are required to import the *.bil images into Arc/Info via the imagegrid command.

The *.rdc file is required for use in IDRISI32, together with the included *.rst files. In some cases, the *.rdc files are also required by Arc/Info usersto identify the legend of a raster image.

Furthermore, for each plate a *.bmp and a *emf file is available. They can be viewed in suitable graphics software (e.g. Microsoft Paint, CorelDraw, etc. on the PC or XV, ghostview ... under Unix).

All images:

- C over the whole globe
- Are in geographic projection, i.e. in longitude, latitude
- The corner point of the upper left corner is at: -180 x-coord and +90 y-coord.
- Use the INTEL byte order to store integers

There are four different image sizes:

1. cell size: 0.5 degree
   360 rows, 720 columns
   1 byte integer
   *.bil file = 259200 bytes
2. cell size: 0.5 degree
   360 rows, 720 columns
   2 byte integer
   *.bil file = 518400 bytes
3. cell size: 5 arc-minute
   2160 rows, 4320 columns
   1 byte integer
   *.bil file = 9331200 bytes
4. cell size: 5 arc-minute
   2160 rows, 4320 columns
   2 byte integer
   Size of *.bil file is 18662400 bytes

Remarks for Arc/Info users:
Negative values in the images (such as -9999 for nodata) are imported into Arc/Info as positve values by adding 65536. ( For example in plate01, the value 55537 should be changed to -9999 for nodata (55537 - 65536 = -9999). The setnull command may be used to introduce nodata.)