<div dir="ltr"><div class="gmail_default" style="font-size:small">Manisha,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">If you don't have the lat/lon information, then one way you plot it in NCL is to provide the exact map parameters, and then make sure you set:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">res@tfDoNDCOverlay = True</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">which tells NCL not to try to transform the plot using map projection equations, because the transformation has already been done.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">You may also need to set:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">res@gsnAddCyclic = False</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">so NCL doesn't try to add a longitude cyclic point.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">There's an example on our "native grid" example page. See "native_1.ncl" at:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/native.shtml#ex1">http://www.ncl.ucar.edu/Applications/native.shtml#ex1</a><br></div><div class="gmail_default"><br></div><div class="gmail_default"><br></div><div class="gmail_default">Note the script has the following resources set, which defines the projection that the data was calculated on:</div><div class="gmail_default"><br></div><div class="gmail_default"><div class="gmail_default"><font face="monospace, monospace">; The following resources are Required to plot this projection correctly</font></div><div class="gmail_default"><font face="monospace, monospace"><br></font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpProjection = "Stereographic" ; projection</font></div><div class="gmail_default"><font face="monospace, monospace"><br></font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpLimitMode = "Corners" ; method to zoom</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpLeftCornerLatF = lat(0,0)</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpLeftCornerLonF = lon(0,0)</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpRightCornerLatF = lat(nlat-1,nlon-1)</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpRightCornerLonF = lon(nlat-1,nlon-1)</font></div><div class="gmail_default"><font face="monospace, monospace"><br></font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpRelativeCenterLon = True ; set a center lon</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpCenterLonF = lon((nlat/2)+1,(nlon/2)+1) ; center lon</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpRelativeCenterLat = True<span style="white-space:pre"> </span> ; set a center lat</font></div><div class="gmail_default"><font face="monospace, monospace"> res@mpCenterLatF = 90. ; center lat</font></div><div class="gmail_default"><font face="monospace, monospace"> res@tfDoNDCOverlay = True ; do not transform data</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">Hopefully you have this information for your own projection and can do something similar. Note that you will need to provide the lat/lon corners yourself. This particular example actually had the 2D lat/lon data, and just used the end points to set the corners.</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">--Mary</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jul 13, 2017 at 3:56 PM, Manisha Ganeshan <span dir="ltr"><<a href="mailto:manisha.ganeshan86@gmail.com" target="_blank">manisha.ganeshan86@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Thanks, Dennis! I'm trying to geo reference the data to plot it on a polar stereographic map projection. But I only have information regarding the map projection and grid spacing in km (below). Can NCL perform coordinate transformation to estimate lat lon variables from the given information? I think the data is intended for use with ArcGIS and similar software so they don't come with lat lon coordinates.<div><br></div><div>Thanks,</div><div>Nisha<br><h3 class="m_-3510899066501568850m_-7730635194702122778gmail-I2" style="padding:0px;outline:none;font-family:Interval,"Arial Narrow",Arial,sans-serif;font-size:1.5em;font-weight:normal;color:rgb(11,75,194);margin:12px 0px 6px">Projection</h3><div><span style="color:rgb(68,68,68);font-family:Arial,Helvetica,sans-serif;font-size:13px">World Geodetic System 1984 (WGS 84) is the reference ellipsoid and datum. The projection is polar stereographic with a standard parallel of 71° S and origin of the South Pole.</span> </div><div><br></div><div><h3 class="m_-3510899066501568850m_-7730635194702122778gmail-I2" style="padding:0px;outline:none;font-family:Interval,"Arial Narrow",Arial,sans-serif;font-size:1.5em;font-weight:normal;color:rgb(11,75,194);margin:12px 0px 6px">Grid Description</h3><p class="m_-3510899066501568850m_-7730635194702122778gmail-I2" style="padding:0px;outline:none;margin:5px 0px 12px;color:rgb(68,68,68);font-family:Arial,Helvetica,sans-serif;font-size:13px">The grid is a 1 km grid of 5601 by 5601 grid boxes centered symmetrically about the pole. Grid size of 1 km is an optimization of resolution and interpolated cells, resulting in less than 32 percent of grid cells having interpolated values.</p></div></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Sun, Jul 9, 2017 at 9:18 AM, Dennis Shea <span dir="ltr"><<a href="mailto:shea@ucar.edu" target="_blank">shea@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">The attached does a simple read-and-plot. The plot does not have any geographic referencing. <br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="m_-3510899066501568850h5">On Sat, Jul 8, 2017 at 9:01 PM, Manisha Ganeshan <span dir="ltr"><<a href="mailto:manisha.ganeshan86@gmail.com" target="_blank">manisha.ganeshan86@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="m_-3510899066501568850h5"><div dir="ltr">Hi Barry, <div><br></div><div>I found some info on ENVI header files, and was able to figure out the data format, dimensions, and read the data successfully. Still trying to figure out the map and projection details, but I think that will be easier to do. Will let you know if I have further trouble.</div><div><br></div><div>Thanks,</div><div>Nisha</div></div><div class="m_-3510899066501568850m_7816615900065393996HOEnZb"><div class="m_-3510899066501568850m_7816615900065393996h5"><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jul 8, 2017 at 9:49 PM, Manisha Ganeshan <span dir="ltr"><<a href="mailto:manisha.ganeshan86@gmail.com" target="_blank">manisha.ganeshan86@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear NCL community,<div><br></div><div>I'm trying to read a binary file without much success. I have tried asciiread and fbindirread functions, but the problem is I'm not sure what to enter in the data type field. There is not much information in the header file nor in the data description (web link below). The variable I am expecting to read is surface elevation (likely in meters), but no matter what data format I attempt to read, I don't seem to get reasonable values. Any leads on how to proceed will be much appreciated. The actual binary data file and the header file are available for download from the weblink below.</div><div><br></div><div>Thanks,</div><div>Nisha</div><div><div><br></div><div>Weblink describing the data</div><div><b><u><font size="4"><a href="http://nsidc.org/data/nsidc-0422" target="_blank">http://nsidc.org/data/nsidc-04<wbr>22</a></font></u></b><br></div><div><br></div><div><br></div><div>Download link for binary file and header file</div><div><strong style="color:rgb(0,0,0);font-family:Arial,Helvetica,sans-serif;font-size:18px;text-align:center"><a href="https://opendrive.gsfc.nasa.gov/shortauth/z/b3zIg8ah" style="color:black" target="_blank">https://opendrive.gsfc.nasa.go<wbr>v/shortauth/z/b3zIg8ah</a></strong><span class="m_-3510899066501568850m_7816615900065393996m_-2552431281604503985HOEnZb"><font color="#888888"><br></font></span></div><span class="m_-3510899066501568850m_7816615900065393996m_-2552431281604503985HOEnZb"><font color="#888888">-- <br><div class="m_-3510899066501568850m_7816615900065393996m_-2552431281604503985m_166642072412607819gmail_signature"><div dir="ltr">Dr. Manisha Ganeshan<div>Universities Space Research Association</div><div>Maryland, U.S.A.</div></div></div>
</font></span></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="m_-3510899066501568850m_7816615900065393996m_-2552431281604503985gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Dr. Manisha Ganeshan<div>Universities Space Research Association</div><div>Maryland, U.S.A.</div></div></div>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="m_-3510899066501568850gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Dr. Manisha Ganeshan<div>Universities Space Research Association</div><div>Maryland, U.S.A.</div></div></div>
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