<div dir="ltr"><div class="gmail_default" style="font-size:small">Hi Samar,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">You can use the shapefile_mask_data function to return a mask of your data at the first time step. You need to set the special "return_mask" attribute to True, so the 0/1 mask array is returned.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">You can then use this mask to apply it to the other time steps of your data. This is assuming that your lat/lon grid is the same for every time step. Is that true for your dataset?</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">I've attached an example that takes a global dataset and uses the USA_adm0.shp shapefile to mask the values over the United States. The comments of the file indicate where you can download the data files needed to run this example.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">The masking can take awhile (about 192 CPU seconds). Once you have the mask array, however, masking the rest of your data should be faster, using the "mask" function.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">--Mary</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Mar 23, 2016 at 9:26 PM, Samar Min Allah <span dir="ltr"><<a href="mailto:minallah@umich.edu" target="_blank">minallah@umich.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"><div class="gmail_default"><span style="color:rgb(7,55,99)">Hello,<br><br></span></div><div class="gmail_default"><span style="color:rgb(7,55,99)">I have a shapefile of a basin (irregular polygon) and I want to use it to clip a netcdf file (i.e, select only the points lying inside the shapefile).<br><br></span></div><div class="gmail_default"><span style="color:rgb(7,55,99)">There is an example that does the same on a 2d array however I have a variable with (time, lat, lon) coordinates for which this does not work;<br><br><a href="https://www.ncl.ucar.edu/Applications/Scripts/shapefiles_4.ncl" target="_blank">https://www.ncl.ucar.edu/Applications/Scripts/shapefiles_4.ncl</a><br><br></span></div><div><span style="color:rgb(7,55,99)">I am having a hard time modifying this to 3d. <div class="gmail_default" style="color:rgb(7,55,99);display:inline">Looping through all the time (thousands of values) is not feasible.</div><br><div class="gmail_default" style="color:rgb(7,55,99);display:inline">I</div>s it possible to mask the variable and output it as a separate netcdf or alternatively subset a</span><div class="gmail_default" style="display:inline"><span style="color:rgb(7,55,99)"> netcdf with irregular polygon.<br><br></span></div><div class="gmail_default" style="color:rgb(7,55,99);display:inline">Thanks<br></div><font size="2"><span style="font-family:courier new,monospace"><span style="color:rgb(153,153,153)">--<br></span></span></font></div><div><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div><div><div><div><font size="2"><span style="font-family:courier new,monospace"><span style="color:rgb(153,153,153)">Samar</span></span></font><br><div><div><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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