WARNING: Idrisi's definition of a projection may not exactly
match that of ARC/INFO or ArcView. Be sure to compare false eastings,
scale factors, etc. A difference in a scale factor of .00003333 may
mean a 60 foot shift or more when laying vector data over the image.
Also, the projection engine used by ARC/INFO and ArcView is not
identical that used by Idrisi; in most cases, however, the difference
should not be more than 0.5 meters.
Displaying Idrisi Images in ArcView
If you're using ArcView Version 3.1 or greater, you may display Idrisi
images directly using the AVIdris extension. For more information,
Exporting Idrisi Images to ArcView
There are two basic export options: ERDAS and TIFF. ERDAS format may
be exported in one step, but cannot be compressed and requires setting
up a colormap in ArcView. TIFF format may be compressed and requires no
colormap, but exporting and georeferencing is a two-step process. Of
the two formats, ArcView seems to print TIFF much more efficiently.
Exporting to ERDAS
1) Use ERDIDRIS to export the image to a .GIS file.
ERDIDRIS x 3 drg drg.gis
2) Use PALETTE WORKSHOP to export the palette (.SMP) to a .PAL
file (no Macro command available).
3) In ArcView, run the script View.LoadGIS to load the image as a theme
and assign color values from the .PAL file.
USGS Digital Raster Graphic (DRG) images use a standard palette. The
script View.LoadDRG will load the image
as a theme in ArcView and assign the standard DRG palette without need
to create a .PAL file.
Exporting to TIFF
1) Use TIFIDRIS to export the image to a .TIF file, specifying
the name of the palette to be used.
TIFIDRIS x 2 drg drg 90 drg
2) Create a world file (.TFW) containing the georeferencing
information. The program WORLD.EXE,
executable from the MS-DOS prompt, reads the document file of the image
and generates the appropriate world file. For example:
world drg drg
3) [Optional, highly recommended] If compression is
desired, use a third-party program (e.g. Corel Photo-Paint or Image
Alchemy) to convert the image to TIFF with packbit compression. ArcView
handles packbit compressed TIFF images much more efficiently than