[Proj] hammer parameters?

William Kyngesburye woklist at kyngchaos.com
Wed Jan 19 14:47:39 EST 2011

So, can anyone tell me what the M and W parameters mean, or at least what values to use to get the Breisemeister (without using ob_tran)?

On Jan 13, 2011, at 11:01 AM, William Kyngesburye wrote:

> On Jan 12, 2011, at 5:33 PM, Frank Warmerdam wrote:
>> Folks,
>> For what it is worth, it is possible to embed a literal PROJ.4 string
>> in GDAL/OGR WKT in which case that will be used as the translation to
>> PROJ.4 format.
>> eg.
>> PROJCS["UTM Zone 11, Northern Hemisphere",
>>    GEOGCS["WGS 84",
>>        DATUM["WGS_1984",
>>            SPHEROID["WGS 84",6378137,298.257223563,
>>                AUTHORITY["EPSG","7030"]],
>>            TOWGS84[0,0,0,0,0,0,0],
>>            AUTHORITY["EPSG","6326"]],
>>        PRIMEM["Greenwich",0,
>>            AUTHORITY["EPSG","8901"]],
>>        UNIT["degree",0.0174532925199433,
>>            AUTHORITY["EPSG","9108"]],
>>        AUTHORITY["EPSG","4326"]],
>>    PROJECTION["Transverse_Mercator"],
>>    PARAMETER["latitude_of_origin",0],
>>    PARAMETER["central_meridian",-117],
>>    PARAMETER["scale_factor",0.9996],
>>    PARAMETER["false_easting",500000],
>>    PARAMETER["false_northing",0],
>>    UNIT["Meter",1],
>>    EXTENSION["PROJ4","+proj=utm +zone=11 +datum=WGS84 +wktext"]]
>> When passing proj.4 strings to GDAL utilities which take
>> PROJ.4 as input you can include the +wktext option to force
>> literal inclusion of the PROJ.4 string.  For projections
>> completely not supported by GDAL you will need to create
>> WKT with some sort of fake projection (perhaps just use
>> the above and update the EXTENSION[] portion.
> I tried this a few months ago for another unsupported projection in GDAL with no luck.  Doesn't work here either.  Quote from Evan Rouault:
> "+wktext cannot help when OSR doesn't recognize the projection. It only helps 
> to keep the extra options that OSR doesn't handle by itself."
> So, if GDAL doesn't support ob_tran, +wktext won't help.
> -----
> William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
> http://www.kyngchaos.com/
> First Pogril: Why is life like sticking your head in a bucket filled with hyena offal?
> Second Pogril: I don't know.  Why IS life like sticking your head in a bucket filled with hyena offal?
> First Pogril: I don't know either.  Wretched, isn't it?
> -HitchHiker's Guide to the Galaxy
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William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>

All generalizations are dangerous, even this one.

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