[Gdal-dev] saving GeoTiff

[Frank Warmerdam]

Ayman Kamal wrote:
> Thank you very much sir, 
> but still I have one point not clear enough: "pixel
> sie", I want to ask the user to supply me with the
> needed data, Shall I put in the dialog "pixel size"
> 
> please I need to understand this point correctly.

Ayman,

I can't easily judge what is appropriate for your dialogs.  It might well
be that your users will have no idea what the size of a pixel is, and will
want to give the top left, and bottom right lat/long coordiantes for an
image from which you will need to derive the pixel size.

> By the way, I figured out that there are vertical
> DATUMs like NAVD, are they supported in GDAL?

GDAL has no support for vertical datums.  The OGC Well Known Text format
used by GDAL for representing coordinate systems does support compound
coordinate systems which include a vertical datum, but GDAL (and the
OGRSpatialReference) do *not* support these, much less use them for anything
useful.

Best regards,

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