<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>It sounds like you will need to do something like this:</div><div><br></div><div>1. Create a file listing all the grid points in or near India (e.g., within a simple latitude and longitude range that covers all of India and some surrounding areas).</div><div><br></div><div>2. Import this list into a GIS program and intersect it with India's land area.</div><div><br></div><div>3. Export a list of Indian grid points from the GIS program.</div><div><br></div><div>4. Import this list into GRADS.</div><div><br></div><div>Step 1 would be easy to do, e.g., in a text (.csv) file created in Excel, if your grid is regularly spaced.</div><div><br></div><div>Step 2 and 3 are easy if you have a GIS program and difficult otherwise. I could help you with that if you want.</div><div><br></div><div>I don't know how you would do Step 4. I can easily create a text file listing all the relevant points, but I don't know how you would reference that text file from GRADS to create a mask variable. Anyone else have ideas about this?</div><div><br></div><div>Matthias</div><br><div><div class="gmail_quote">On Tue, Oct 27, 2009 at 7:23 AM, Sachin Ghude <span dir="ltr"><<a href="mailto:sachinghude@tropmet.res.in">sachinghude@tropmet.res.in</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); margin-top: 0pt; margin-right: 0pt; margin-bottom: 0pt; margin-left: 0.8ex; padding-left: 1ex; position: static; z-index: auto; "> Hi,<br> <br> I want to plot tropospheric NO2 only over the Indian grid points (not Nepal, Pakistan<br> and BanglaDesh). Is there any such utility so that it will enable me to plot data only<br> for India girds in GRADs. ( my grid size is 0.25 x 0.25 degrees).<br> <br> please do the needful..<br> <br> bye..<br> <font color="#888888"><br> Sachin<br> </font></blockquote></div></div><br></body></html>