<div dir="ltr">Hi Scott,<div><br></div><div>I talked this over with Mary, and the map projection shouldn't matter. The regridder works in lat/lon space and knows how to handle curvilinear lat/lon coordinates, so it doesn't care about the projected "meters" space from the map projection transformation. Since you have the lat/lons for each grid box, it's going to regrid your data to the same lat/lon points on your destination grid (which you can plot via the same lambert settings). Note that the lat/lons are for the center of the grid cell, and if you have any missing/fill values in your source data, you need to supply a mask for these points or you'll get some weird artifacts.</div><div><br></div><div>Hope this helps,</div><div><br></div><div>Bill</div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Dec 7, 2018 at 12:47 PM Scott Capps <<a href="mailto:scapps@atmosdatasolutions.com" target="_blank">scapps@atmosdatasolutions.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Thank you. Yes, I have lat and lon values and could use the ESMF regridding functions. However, these lat lons are on different map projections and I wondering if the necessary reprojection is handled using the ESMF regridding software. <br><div class="gmail_quote"><div dir="ltr">On Fri, Dec 7, 2018 at 9:29 AM Bill Ladwig <<a href="mailto:ladwig@ucar.edu" target="_blank">ladwig@ucar.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr">Hi Scott,<div><br></div><div>You know what, I think you already have the lat/lon values for both your source and destination grids at each grid point, so you can bypass that map projection stuff and go right to the ESMF regridder. There's plenty of examples here: <a href="https://www.ncl.ucar.edu/Applications/ESMF.shtml" target="_blank">https://www.ncl.ucar.edu/Applications/ESMF.shtml</a>. You'll be going from a rectilinear grid to a curvilinear grid. This example is similar, but you'll want to go in the opposite direction: <a href="https://www.ncl.ucar.edu/Applications/Scripts/ESMF_all_5.ncl" target="_blank">https://www.ncl.ucar.edu/Applications/Scripts/ESMF_all_5.ncl</a></div><div><br></div><div>Hope this helps,</div><div><br></div><div>Bill</div></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Dec 6, 2018 at 7:06 PM Scott Capps <<a href="mailto:scapps@atmosdatasolutions.com" target="_blank">scapps@atmosdatasolutions.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Thank you. I have looked at that function and I don't think it will work. It would need to accept as input the 1D lat (y) and lon (x) variables and output two lat2d and lon2d variables. Not sure what the "z" input is (I was not able to find the source code for this function). <div><br></div><div><div>wgsfile = addfile("./<a href="http://territory_slope_2km_epsg4326.nc" target="_blank">territory_slope_2km_epsg4326.nc</a>","r")</div><div>x = wgsfile->lon</div><div>y = wgsfile->lat</div><div>printVarSummary(x) ; [lon | 385]</div><div>printVarSummary(y) ; [lat | 359]</div><div>; To reproject to WRF, must relabel as spherical lat/lon (even though the file is in WGS84 ellipsoid):</div><div>SrcProjStr = "+proj=latlong +a=6370 +b=6370 +towgs84=0,0,0 +no_defs"</div><div>; LCC WRF using truelats, center_lons, etc..</div><div>DestProjStr = "+proj=lcc +lat_1=30.0 +lat_2=41.0 +lat_0=35.80001 +lon_0=-120.095 +a=6370 +b=6370 +towgs84=0,0,0 +no_defs"</div><div><br></div><div>transform_coordinate(SrcProjStr, DestProjStr, x, y, z)</div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Dec 6, 2018 at 1:53 PM Bill Ladwig <<a href="mailto:ladwig@ucar.edu" target="_blank">ladwig@ucar.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">Hi Scott,<div><br></div><div>See this: <a href="http://mailman.ucar.edu/pipermail/ncl-talk/2016-October/007059.html" target="_blank">http://mailman.ucar.edu/pipermail/ncl-talk/2016-October/007059.html</a></div><div><br></div><div>Remember when setting up the Proj4 Lambert Conformal string for WRF to use a sphere with a radius of 6370000. I believe that function will give you fractional x,y values, which you'll need to do some kind of interpolation (or nearest neighbor if that's good enough) to do your computation.</div><div><br></div><div>Hope this helps,</div><div><br></div><div>Bill</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Wed, Dec 5, 2018 at 1:58 PM Scott Capps <<a href="mailto:scapps@atmosdatasolutions.com" target="_blank">scapps@atmosdatasolutions.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><br></div>I have created a NetCDF file with data (terrain slope) on the WGS84 4326 map projection (ncdump -h output shown below):</div><div dir="ltr"><br clear="all"><div><div>dimensions:</div><div><span style="white-space:pre-wrap"> </span>lon = 27382 ;</div><div><span style="white-space:pre-wrap"> </span>lat = 25569 ;</div><div>variables:</div><div><span style="white-space:pre-wrap"> </span>char crs ;</div><div><span style="white-space:pre-wrap"> </span>crs:grid_mapping_name = "latitude_longitude" ;</div><div><span style="white-space:pre-wrap"> </span>crs:long_name = "CRS definition" ;</div><div><span style="white-space:pre-wrap"> </span>crs:longitude_of_prime_meridian = 0. ;</div><div><span style="white-space:pre-wrap"> </span>crs:semi_major_axis = 6378137. ;</div><div><span style="white-space:pre-wrap"> </span>crs:inverse_flattening = 298.257223563 ;</div><div><span style="white-space:pre-wrap"> </span>crs:spatial_ref = "GEOGCS[\"WGS 84\",DATUM[\"WGS_1984\",SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433],AUTHORITY[\"EPSG\",\"4326\"]]" ;</div><div><span style="white-space:pre-wrap"> </span>crs:GeoTransform = "-121.3651264724438 0.0002790528478797247 0 39.07036311976184 0 -0.0002790528478797247 " ;</div><div><span style="white-space:pre-wrap"> </span>double lat(lat) ;</div><div><span style="white-space:pre-wrap"> </span>lat:standard_name = "latitude" ;</div><div><span style="white-space:pre-wrap"> </span>lat:long_name = "latitude" ;</div><div><span style="white-space:pre-wrap"> </span>lat:units = "degrees_north" ;</div><div><span style="white-space:pre-wrap"> </span>double lon(lon) ;</div><div><span style="white-space:pre-wrap"> </span>lon:standard_name = "longitude" ;</div><div><span style="white-space:pre-wrap"> </span>lon:long_name = "longitude" ;</div><div><span style="white-space:pre-wrap"> </span>lon:units = "degrees_east" ;</div><div><span style="white-space:pre-wrap"> </span>float Band1(lat, lon) ;</div><div><span style="white-space:pre-wrap"> </span>Band1:long_name = "GDAL Band Number 1" ;</div><div><span style="white-space:pre-wrap"> </span>Band1:_FillValue = -9999.f ;</div><div><span style="white-space:pre-wrap"> </span>Band1:grid_mapping = "crs" ;</div><div><br></div><div>// global attributes:</div><div><span style="white-space:pre-wrap"> </span>:GDAL_AREA_OR_POINT = "Area" ;</div><div><span style="white-space:pre-wrap"> </span>:Conventions = "CF-1.5" ;</div><div><span style="white-space:pre-wrap"> </span>:GDAL = "GDAL 2.3.2, released 2018/09/21" ;</div><div><span style="white-space:pre-wrap"> </span>:history = "Wed Dec 05 11:41:45 2018: GDAL CreateCopy( <a href="http://territory_epsg4326_slope.nc" target="_blank">territory_epsg4326_slope.nc</a>, ... )" ;</div><div>}</div></div><div><br></div><div>And, I would like to calculate the average terrain slope in each grid cell on my coarser WRF domain (2km resolution). </div><div><br></div><div>Can NCL correctly handle the re-projection from the file above:</div><div><br></div><div><div>Geodetic CRS: WGS84</div><div>Datum: World Geodetic System 1984</div><div>Ellipsoid: WGS 84</div><div>Prime Meridian: Greenwich</div></div><div><br></div><div>to my WRF Lambert Conformal Conic projection while calculating the average terrain slope in each overlapping, coarser resolution WRF gridcell? </div><div><br></div><div>Any help or suggestions are appreciated.</div><div><br></div><div>Thank you,</div><div><br></div><div>Scott</div></div></div></div></div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail-m_-9118807807117269878m_3379601582662514344m_2043876464822928448m_-4551911700466919708gmail_signature"><div dir="ltr"><div><div dir="ltr"><b><font size="4">Scott Capps</font></b><div>Principal</div><div><a href="http://www.atmosphericdatasolutions.com" target="_blank">Atmospheric Data Solutions</a></div><div><a href="mailto:scapps@atmosdatasolutions.com" target="_blank">scapps@atmosdatasolutions.com</a><div>cell: (949) 910-4385</div><div><br></div></div></div></div></div></div>
</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail-m_-9118807807117269878m_3379601582662514344gmail_signature"><div dir="ltr"><div><div dir="ltr"><b><font size="4">Scott Capps</font></b><div>Principal</div><div><a href="http://www.atmosphericdatasolutions.com" target="_blank">Atmospheric Data Solutions</a></div><div><a href="mailto:scapps@atmosdatasolutions.com" target="_blank">scapps@atmosdatasolutions.com</a><div>cell: (949) 910-4385</div><div><br></div></div></div></div></div></div></div>
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