<div dir="ltr">Hi,<div><br></div><div>Answering your second question first, NCL does not write shapefiles. </div><div><br></div><div>Example #2 shows using the ind() function to find the indices of a subset of "features". I am unfamiliar with the plot_shapefile() function, but as it only takes a filename as input, I don't see how it could be used to draw that subset, so you would have to draw it yourself. In the case of a point shapefile, as in Example 2, this was easy. In the case of lines or polygons, you'll have to draw them explicitly by looping over the geometry indices identified via the ind(). Example #1 shows such drawing.</div><div><br></div><div><a href="http://ncl.ucar.edu/Applications/shapefiles.shtml">http://ncl.ucar.edu/Applications/shapefiles.shtml</a><br></div><div><br></div><div>Finally, you might be able to use GDAL's "ogr2ogr" command to subset and write a new shapefile, and plot that with NCL using plot_shapefile(). It definitely reads/writes shapefiles, and it allows you to specify an SQL-like "WHERE..." clause to subset your data. I've personally not used ogr2ogr in this fashion, so it might take some experimentation.</div><div><br></div><div>Good luck...</div><div>Rick</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Apr 6, 2020 at 6:27 AM Lyndz via ncl-talk <<a href="mailto:ncl-talk@ucar.edu">ncl-talk@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"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Dear NCL-experts,</div><div><br></div><div>I am plotting a shapefile based on the basic commands provided in the NCL webpage.</div><div><br></div><div>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">ncl 1> load = "../shapefile_utils.ncl"<span> </span></font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">ncl 2> sname</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">ncl 2> sname="PHL_climatetype.shp"</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">ncl 3> print_shapefile_info(sname)</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span>Filename: "PHL_climatetype.shp"</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Geometry type: polygon</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span># of features: 4</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Min/max lat:<span> </span>4.59/<span> </span>21.12</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Min/max lon:<span> </span>116.93/ 126.61</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Variable names and their types:</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>geometry : integer</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>segments : integer</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>x : double</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>y : double</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Id : integer</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures"><font size="1" color="#ff0000">(0)<span style="white-space:pre-wrap"> </span> <span> </span>Type : double</font></span></p>
<p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><font size="1">(0)</font></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><font size="1"><br></font></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><font size="1"><br></font></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">I want to do the following:</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">[1] The "Type" in the shapefile are numbers 1 to 4. </span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">I would like to select only Type 2 and plot the result.</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">My question is, is it possible to select only the Type 2 in the shapefile and plot it using the plot_shapefile(sname) command?</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">[2] I want to save the selected shapefile in [1] as an independent shapefile. How can I do this in NCL?</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">I'll appreciate any advise on this.</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">Sincerely,</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">Lyndz</span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p><p style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p></div></div></div></div></div></div></div></div></div></div></div></div>
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