[Gdal-dev] Computing histograms for output files

[Andrey Kiselev]

On Fri, Oct 24, 2003 at 11:08:56AM -0400, Frank Warmerdam wrote:
> >I have been using GDAL to create erdas Imagine .img files (i.e. HFA 
> >format). The HFA format includes a histogram of each band as part of its 
> >data structure. When I open these files in Imagine, I can compute a 
> >histogram, and work with the files that way. However, I would like to 
> >open these files directly in ArcGis, and when I open these files in 
> >Arcgis (without previously calculating the histograms in Imagine) ArcGis 
> >crashes.
> There is no current support for adding the histograms. I looked at doing it
> a few weeks ago, but after testing the existing .img output in Imagine I
> came to the conclusion there was no pressing need (at least for that 8bit
> output).  However, your points raise the importance again.

Frank,

It may be another reason for crash. When Imagine calculates histograms
it is also rewrites HFA header structures in ``standard'' way, expected
by the ArcGis. Original headers written by the GDAL may be unsuitable
for ArcGis. I don't know how it could be solved, though.

					Andrey

-- 
Andrey V. Kiselev
Home phone:  +7 812 5274898  ICQ# 26871517