[postgis-users] DEM importing

[jeremy pierre]

That makes sense, thanks!

Jeremy

On Thu, Aug 6, 2009 at 3:36 PM, Frank Warmerdam<warmerdam at pobox.com> wrote:
> jeremy pierre wrote:
>>
>> Hi all,
>>
>> Apologies if this is an extremely newbie-ish post but here goes:
>>
>> I'm working(to scratch an itch) on a library and utility in Scala to
>> import USGS format DEM files into PostGIS as points(probably
>> multipoints really).  I'm working with the CDED files from geobase.ca
>> at present and the quadrangle coordinates are all laid out in
>> arc-seconds.  The question is:  for the x and y coordinates of each
>> elevation point would it be better(across the board, given various
>> types of DEM data) to keep points as lat/long floats(convert from the
>> arc seconds) or stick to arc-seconds as a standard unit for importing?
>>  Anyone care to weigh in on this?
>>
>> Again, apologies if I'm being a terrible newbie...
>
> Jeremy,
>
> My position would be that you are better off converting from arcseconds
> to decimal degrees as it gives you the opportunity to use the reprojection
> mechanisms of PostGIS if you want.  The PostGIS transform code does not
> understand geographic (angular) units other than decimal degrees.
>
> 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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