<div dir="ltr"><div>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. </div><div><br></div>PROJCS["1/1.0 LFM",GEOGCS["NOT SPECIFIED",DATUM["SPHERE",<wbr>SPHEROID["SPHERE",6371200.0,0.<wbr>0]],PRIMEM["Greenwich",0.0],<wbr>UNIT["Degree",0.<wbr>0174532925199433]],PROJECTION[<wbr>"Stereographic_North_Pole"],<wbr>PARAMETER["False_Easting",11.<wbr>0],PARAMETER["False_Northing",<wbr>41.0],PARAMETER["Central_<wbr>Meridian",-105.0],PARAMETER["<wbr>Standard_Parallel_1",60.0],<wbr>PARAMETER["Scale_Factor",1],<wbr>UNIT["190500.0 meters",190500.0]]<br><div><br></div><div>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.</div><div><br></div><div>PROJCS["1/40.0 LFM",GEOGCS["NOT SPECIFIED",DATUM["SPHERE",<wbr>SPHEROID["SPHERE",6371200.0,0.<wbr>0]],PRIMEM["Greenwich",0.0],<wbr>UNIT["Degree",0.<wbr>0174532925199433]],PROJECTION[<wbr>"Stereographic_North_Pole"],<wbr>PARAMETER["False_Easting",401.<wbr>0],PARAMETER["False_Northing",<wbr>1601.0],PARAMETER["Central_<wbr>Meridian",-105.0],PARAMETER["<wbr>Standard_Parallel_1",60.0],<wbr>PARAMETER["Scale_Factor",1],<wbr>UNIT["4762.5 meters",4762.5]]<br></div><div><br></div><div>Good luck!</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jul 14, 2017 at 8:56 AM, Patrick L. Francis <span dir="ltr"><<a href="mailto:wxprofessor@gmail.com" target="_blank">wxprofessor@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div><div><span style="font-size:12pt"><br></span></div><div><span style="font-size:12pt">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! </span><img src="cid:Oi0p" alt=":-)" height="24" width="24" style="font-size:12pt"><span style="font-size:12pt"> lol</span></div><div id="m_5300835855382677723x2d2e0dcc51e6462"><div><br></div><div>this projection:</div><div><a href="http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html#GRID202" target="_blank">http://www.nco.ncep.noaa.gov/<wbr>pmb/docs/on388/tableb.html#<wbr>GRID202</a></div><div><br></div><div>when applied via gdal_translate and converted to mercator, results in.. how to describe? well here is a screenshot if you are interested</div><div><a href="http://www.blindleper.com/files/gdal/gdal_warp_merc.jpg" target="_blank">http://www.blindleper.com/<wbr>files/gdal/gdal_warp_merc.jpg</a></div><div><br></div><div>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):</div><div><a href="http://www.blindleper.com/files/gdal/original.jpg" target="_blank">http://www.blindleper.com/<wbr>files/gdal/original.jpg</a></div><div><br></div><div>so clearly i'm doing something wrong... I've tried varations of lat_ts like this:</div><div>#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<br>#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<br></div><div><br></div><div>because i'm not sure what "La1 7.838N" and such mean on that projection above...</div><div><br></div><div>Anyway, I hope someone can help lead me away from the dark side and into the light... this is driving me bonkers! <img src="cid:KkFMSUVOKg==" alt="*ALIEN*" height="24" width="24" style="font-size:12pt"></div><div><br></div><div>cheers,</div><div><br></div><div>--BlindLeper</div><div><br></div><div><br></div><div><br></div><div><br></div><div>..</div><div><br></div>
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