[Gdal-dev] Extracting Geo Info From GeoTiff's

[Ed McNierney]

Theuns -

Concerning such "confidential" disclaimers, I have been advised by
attorneys that if one labels EVERYTHING "confidential" but you don't
treat it as such, you are putting your REALLY confidential material at
significant risk.  Someone who disclosed information you really meant to
keep confidential could reasonably argue that your "confidential" labels
are meaningless and no one can figure out which information is
confidential and which is not.  You should pass that comment on to the
folks who are labeling every email as "private and confidential"....

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242  

-----Original Message-----
From: gdal-dev-bounces at lists.maptools.org
[mailto:gdal-dev-bounces at lists.maptools.org] On Behalf Of Frank
Warmerdam
Sent: Thursday, October 13, 2005 11:42 AM
To: Theuns Heydenrych
Cc: gdal-dev at lists.maptools.org
Subject: Re: [Gdal-dev] Extracting Geo Info From GeoTiff's

On 10/13/05, Theuns Heydenrych <Theuns at softsim.co.za> wrote:
> I did read through the source code to get a feeling where to start.
> As far as I can figure out , I have to use the function GTIFGetDefn to

> get a definition structure back with the information , but the 
> function obviously requires a handle to the Geotiff file.
> This handle can be obtained from using the GTIFNew Function.

Theuns,

You are digging into too low a level.  Normally you would call
GetProjectionRef() on the GDALDataset to get the coordinate system
information (expressed in OGC Well Known Text), and
GetGeoTransform() to get the affine transformation between pixel/line
and georeferenced coordinates.

You aren't supposed to be calling any of the GTIF functions directly.

If you need detailed and exact information about the GeoTIFF as the
original geotiff tags then you should likely be using libgeotiff
directly.

> Disclaimer:
> The information contained in this communication is private and 
> confidential and is intended solely for use by the
individual/individuals or entity to
> whom it is addressed.  Kindly notify the sender immediately by
e-mail if
> you have received this communication by mistake and delete this e-mail

> from your system.  Any unauthorized use or interception of this 
> communication, or the review, retransmission, dissemination or other 
> use of, or taking any action in reliance upon the contents, by 
> individuals or entities other than those intended, is strongly
prohibited.

Such a disclaimer is pretty lame on a public mailing list.  I would
encourage you to pass on to your management that it makes your
organization look ... disfunctional.

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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