[gdal-dev] Validating a projection

[Doug McCorkle]

> On Jun 7, 2015, at 1:16 PM, Andre Joost <andre+joost at nurfuerspam.de> wrote:
> 
> Am 07.06.2015 um 18:50 schrieb Doug McCorkle:
>> Hello,
>> 
>> I am trying to add this projection to our runtime environment:
>> 
>> PROJCS["USA_Contiguous_Albers_Equal_Area_Conic_USGS_version",
>> GEOGCS["GCS_North_American_1983", DATUM["D_North_American_1983",
>> SPHEROID["GRS_1980",6378137.0,298.257222101]],
>> PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433],
>> AUTHORITY["EPSG","4269"]], PROJECTION["Albers_Conic_Equal_Area"],
>> PARAMETER["False_Easting",0.0], PARAMETER["False_Northing",0.0],
>> PARAMETER["Central_Meridian",-96.0],
>> PARAMETER["Standard_Parallel_1",29.5],
>> PARAMETER["Standard_Parallel_2",45.5],
>> PARAMETER["Latitude_Of_Origin",23.0], UNIT["Meter",1.0],
>> AUTHORITY["EPSG","102039”]]
>> 
> 
>> When I try to validate the projection I get this in the debug
>> output:
>> 
>> OGRSpatialReference::Validate: PARAMETER Central_Meridian for
>> PROJECTION Albers_Conic_Equal_Area is an alias for
>> longitude_of_center.
>> 
>> I am unsure of what to do with this debug information to correct the
>> definition. This is the proj4 definition:
>> 
>> # USA Contiguous Albers Equal Area Conic USGS version <102039>
>> +proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23.0 +lon_0=-96 +x_0=0
>> +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs <>
>> 
> 
> If you run gdalsrsinfo on this proj.4 string, you get the following WKT output:
> 
> PROJCS["unnamed",
>    GEOGCS["NAD83",
>        DATUM["North_American_Datum_1983",
>            SPHEROID["GRS 1980",6378137,298.257222101,
>                AUTHORITY["EPSG","7019"]],
>            TOWGS84[0,0,0,0,0,0,0],
>            AUTHORITY["EPSG","6269"]],
>        PRIMEM["Greenwich",0,
>            AUTHORITY["EPSG","8901"]],
>        UNIT["degree",0.0174532925199433,
>            AUTHORITY["EPSG","9108"]],
>        AUTHORITY["EPSG","4269"]],
>    PROJECTION["Albers_Conic_Equal_Area"],
>    PARAMETER["standard_parallel_1",29.5],
>    PARAMETER["standard_parallel_2",45.5],
>    PARAMETER["latitude_of_center",23],
>    PARAMETER["longitude_of_center",-96],
>    PARAMETER["false_easting",0],
>    PARAMETER["false_northing",0],
>    UNIT["Meter",1]]
> 
> So it is really a matter of naming the same parameter. Using longitude_of_center will make all GDAL-dependent software happy, while the Central_Meridian might be invoked by ESRI.
> 
> See also http://www.remotesensing.org/geotiff/proj_list/albers_equal_area_conic.html for the official OGC WKT parameter names.

Andre,

Perfect! Thanks for the quick response and tip. 

Doug