[Gdal-dev] saving GeoTiff

[Ayman Kamal]

ok sir, I figured out that the pixel size decides how
long does the pixel represent in actual model system
units, as the scale factor for geograpich maps,

1. Now I just want to know, for the 4 mentioned
coordinate systems
"NAD27", "NAD83", "WGS72", "WGS84" what are the units
of the model system?? I want to ask the user to
explain this for the user.

2. What are the ranges for valid data the user can
provide for the top left corner of image & for pixel
size.

3. I saved a certain image using GDAL and each time
changed the pixel size,and then opened this image
using GDAL and noticed that there was no difference in
how the image looked like, I am sure of that. Can you
explain?


--- Frank Warmerdam <warmerdam at pobox.com> wrote:
> Ayman Kamal wrote:
> > Then, if it can be derived, how can I do so, If it
> > can't, can you give me more explanation?
> > 
> > If you don't have enough time to answer me, can
> you
> > please givem me a link to a web page or whatsoever
> > resource that explains this. I need to understand
> this
> > point THOROUGHLY.
> 
> Ayman,
> 
> I do not know off hand of a resouce that discusses
> this thoroughly.  I would
> suggest you review the information in the GDAL data
> model document about
> "Affine GeoTransform".
> 
>   
>
http://www.remotesensing.org/gdal/gdal_datamodel.html
> 
> 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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