[mapserver-users] Projection help: proj command line

[Matthew Pettis]

That worked fantastically - Thank You Very Much!

Matt

On Mon, Jun 30, 2008 at 2:05 AM, Dirk Jesko <ml.dje at geocontent.de> wrote:
> Hi Matthew,
>
> try cs2cs instead of proj, e.g.
>
> cs2cs +init=epsg:26915 +to +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0
> +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs
>
>
> With proj you have to do the inverse projection from epsg:26915 (your from
> projection) to latlon/wgs84 (epsg:4326) first,
>
> proj -I -f "%.8f" +init=epsg:26915
>
> In a second step project the resulting latlon coordinate into your
> to-projection:
>
> proj -f "%.4f" +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0
> +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs
>
> Both version should work. Just for comparison, I got the following result
> for the first point of your extent:
>
> epsg:26915        : 184056.505, 4809728.25
> epsg:4326         : -96.89976708 43.37391004
> your to projection: -10786832.7293 5369059.0540
>
> I hope, that this is correct and will help.
>
> Dirk
>
>
>> Hi,
>>
>> This question is tangential to Mapserver, but critical to me
>> nonetheless.  I'm trying to reproject a shapefile in a mapfile from
>>
>> =========================================================
>> PROJECTION
>>    "init=epsg:26915"
>> END
>> =========================================================
>>
>> to
>>
>> =========================================================
>> PROJECTION
>>        "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0
>> +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs"
>> END
>> =========================================================
>>
>> my extent in the 'from' projection are:
>>
>> =========================================================
>> EXTENT      184056.505 4809728.25 767381.245 5478975.75
>> =========================================================
>>
>> Can someone help me figure out what my EXTENT should be in my 'to'
>> projection?  I've tried the following extents derived from the 'proj'
>> command line outputs as extents, but was not successful:
>>
>> =========================================================
>> $ proj -I -f "%.4f" +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0
>> +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null
>> +wktext  +no_defs
>> 184056.505 4809728.25
>> 1.6534  39.6121
>> 767381.245 5478975.75
>> 6.8935  44.0874
>>
>> $ proj -I -f "%.4f" +init=epsg:26915
>> 184056.505 4809728.25
>> -96.8998        43.3739
>> 767381.245 5478975.75
>> -89.3140        49.4047
>> =========================================================
>>
>> Anybody have any ideas what I am doing wrong?  Do I somehow have to
>> chain projections together to get from my 'from' projection to my 'to'
>> projection?
>>
>> Thanks,
>> Matt
>>
>> --
>> It is from the wellspring of our despair and the places that we are
>> broken that we come to repair the world.
>> -- Murray Waas
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>>
>



-- 
It is from the wellspring of our despair and the places that we are
broken that we come to repair the world.
-- Murray Waas