[Gdal-dev] problem with converting GeoTiff to BMP

Frank Warmerdam warmerdam at pobox.com
Sun Mar 23 12:25:36 EST 2003

Ayman Kamal wrote:
> I have a GeoTiff file with the following data
> generated from "gdalinfo". I converted this file using
> "gdal_translate" to a bmp file, it appeared as all
> white, but when I chose to call
> "poVRTBand->AddSimpleSource"
> instead of
> "poVRTBand->AddComplexSource"
> it worked,


Since the primary difference between AddComplexSource() and AddSimpleSource()
is that the complex case includes scaling information, I would *guess* that
you passed in incorrect scaling information.  Of course, there is nowhere
near enough information in your "bug report" to determine what is going wrong
with any authority.  There could even be a bug in GDAL!

If you want serious answers you should work on developing your question
asking skills.  If I ran into the same situation with someone elses library
I would either:

1) reproduce the problem with gdal_translate, and report the bug
in bugzilla *with* the input data to reproduce it and a fairly detailed
explanation of what I think is wrong with the result

or if I couldn't do that, fallback to:

2) Write a minimal C/C++ program that demonstrates the problem (and the
correct alternate behaviour with AddSimpleSource()), bundle it up with small
test data to demonstrate the problem and email the list with a link to the
package demonstrating the problem.

It is clear that your understanding of GDAL is growing and I now have a
greater appreciation that you are a serious developer willing to spend some
time on this.  However the rate you ask questions and the incompleteness of
them is frustrating to me and others who are generally willing to respond.
In short, you are sucking up a disproportionate amount of the good-will
question answering on the list.

Keep asking, but please make every effort to figure stuff out yourself first,
and when you do ask question make ever effort to be considerate of possible
question answerers time.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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