[GRASS-user] Correctly Converting LL to LCC

MS mseibel at gmail.com
Mon Dec 28 11:08:28 EST 2009


Can you setup a lat/long in GRASS, import lat/long points, then  
reproject within GRASS to your LCC projection?

Mark

On Dec 28, 2009, at 10:46 AM, Rich Shepard <rshepard at appl-ecosys.com>  
wrote:

>  I apologize in advance for cross-posting this message, but I need to
> quickly resolve this issue so I can proceed with the project. I  
> posted this
> to the proj4j mail list Friday (yes, I know it was a holiday), but  
> have seen
> no traffic on that list at all, and no responses to this request.  
> Perhaps
> someone here can help me.
>
>  There are three points whose geographic coordinates I have in long/ 
> lat. I
> need to convert these to the Oregon Lambert Conformal Conic  
> projection with
> the Washington-Oregon adjustment. When I try doing this with the  
> cs2cs tool I
> get incorrect values as a result.
>
>  This is the input file:
>
> #longitude|latitude
> 122:30:32.43W|45:19:19.49N
> 122:30:17.92W|45:18:52.45N
> 122:29:34.08W|45:18:47.16N
>
>  This is the command line I used:
>
> cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83  
> +ellps=GRS80 \
> +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336  
> +y_0=0 +nadgrids=WO
>
> The above values are taken from the metadata for the Oregon LCC:
>
> Lambert Conformal Conic
>   stdparll 43.000000
>   stdparll 45.500000
>   long center -120.500000
>   latprj origin 41.750000
>   false east 1312335.958000 (International feet)
>   false north 0.000000
>
>   North American Datum of 1983
>   Geodetic Reference System 80
>   semiaxis 6378137.000000
>   denflat 298.257222
>
>  And these are the results:
>
> #Easting|Northing
> 1154847.51|398797.24
> 1155143.02|397955.05
> 1156093.62|397768.55
>
>  Not only do these seem reversed, they are not at all within the  
> bounds of
> the other project maps.
>
>  I have the middle location on a separate map that was imported to  
> GRASS
> from an ESRI file, and its coordinates are approximately 796758.58,
> 1305792.74. Those values are in easting, northing order (at least,  
> that's
> the way I presume the GRASS-6.4 wxPython display presents them), and  
> differ
> in magnitude from what cs2cs produced.
>
>  What have I done incorrectly? How should I properly translate the  
> long/lat
> values to lcc for my project?
>
> Rich
>
>
>
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