[gdal-dev] stere

Brian McCormick lists at mcbsystems.us
Fri Jul 14 09:43:05 PDT 2017


I work with NWS grids a lot for nexrad data. They are in a 1/40 lfm grid.
Your data looks like it might be an a 1/1 LFM grid. Here is the WKT I would
use for a 1/1 LFM grid. Each cell is 190.5 km.

PROJCS["1/1.0 LFM",GEOGCS["NOT SPECIFIED",DATUM["SPHERE",
SPHEROID["SPHERE",6371200.0,0.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.
0174532925199433]],PROJECTION["Stereographic_North_Pole"],
PARAMETER["False_Easting",11.0],PARAMETER["False_Northing",
41.0],PARAMETER["Central_Meridian",-105.0],PARAMETER["
Standard_Parallel_1",60.0],PARAMETER["Scale_Factor",1],UNIT["190500.0
meters",190500.0]]

A 1/40 lfm grid projection that the NWS uses for the radar looks like so.
The other one above is a wild guess based on the fact that it has a grid
size of 190.5km I am thinking it is their LFM.

PROJCS["1/40.0 LFM",GEOGCS["NOT SPECIFIED",DATUM["SPHERE",
SPHEROID["SPHERE",6371200.0,0.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.
0174532925199433]],PROJECTION["Stereographic_North_Pole"],
PARAMETER["False_Easting",401.0],PARAMETER["False_Northing",
1601.0],PARAMETER["Central_Meridian",-105.0],PARAMETER["
Standard_Parallel_1",60.0],PARAMETER["Scale_Factor",1],UNIT["4762.5
meters",4762.5]]

Good luck!

On Fri, Jul 14, 2017 at 8:56 AM, Patrick L. Francis <wxprofessor at gmail.com>
wrote:

>
> Hello! I have been banging my head against the wall trying to use the
> polar stereographic projection, and am hoping one of you that is smarter
> than me, which would likely be all of you can help! [image: :-)] lol
>
> this projection:
> http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html#GRID202
>
> when applied via gdal_translate and converted to mercator, results in..
> how to describe? well here is a screenshot if you are interested
> http://www.blindleper.com/files/gdal/gdal_warp_merc.jpg
>
> and here is what the original looks like before the projection is assigned
> and warped (I know the merc warp is good, because I use it on many other
> things.. I've just never tried polar stereographic before):
> http://www.blindleper.com/files/gdal/original.jpg
>
> so clearly i'm doing something wrong... I've tried varations of lat_ts
> like this:
> #cs2cs +proj=latlong +datum=WGS84 +to +proj=stere +lat_ts=37 +ellps=WGS84
> +lat_0=90 +lon_0=-105 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs
> #cs2cs +proj=latlong +datum=WGS84 +to +proj=stere +lat_ts=7.838
> +ellps=WGS84 +lat_0=90 +lon_0=-105 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m
> +no_defs
>
> because i'm not sure what "La1 7.838N" and such mean on that projection
> above...
>
> Anyway, I hope someone can help lead me away from the dark side and into
> the light... this is driving me bonkers!  [image: *ALIEN*]
>
> cheers,
>
> --BlindLeper
>
>
>
>
> ..
>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20170714/e6cfff4f/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 849 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20170714/e6cfff4f/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 919 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20170714/e6cfff4f/attachment-0001.png>


More information about the gdal-dev mailing list