<div dir="ltr"><div><div><div><div><div>---<br>re:<br>I have latitude and longitude in cartesian coordinates (example of the
text file is above). That is the only information I have. I plotted the
data before using <font face="arial, helvetica, sans-serif"><span style="font-size:12.8px">gsn_add_polymarker
for the domain I want e.g. 15N 20N and 54W-58W. The center of this
domain is 16.8N and 56W. What the polymaker function did was if I had an
observation at 16N and 53W a black dot was drawn. What I need now
is transform that 16N-53W (black dot) into cylindrical coordinates u<wbr>sing as center </span></font><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">16.8N and 56W. <br>---<br><br></span></div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">This is much more specific. Really, this needs custom built code:<br><br></span></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">[a] The region is quite small and near the equator. Hence, I think you could treat the data as being on a cartesian grid.<br><br> clat = 16.8 ; user specified center point<br> clon = -56.0<br><br> latS = 15.0 ; area of interest; nearish to equator; earth curvature effect is 'small'<br> latN = 20.0<br> lonL = -58.0<br> lonR = -54.0<br></span></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><br></span></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">[b] You can use the 'ind' function to isolate only points with the region of interest:<br> <a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/ind.shtml" target="_blank">https://www.ncl.ucar.edu/<wbr>Document/Functions/Built-in/<wbr>ind.shtml</a><br><br></span></div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">[c] You specified a center point. You could use the following to determine the radius (distance) to each point.<br> <a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/gc_latlon.shtml" target="_blank">https://www.ncl.ucar.edu/<wbr>Document/Functions/Built-in/<wbr>gc_latlon.shtml</a><br><br></span></div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">[d] I think the polar 'theta' can be determined using atan2. <br> <a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/atan2.shtml">https://www.ncl.ucar.edu/Document/Functions/Built-in/atan2.shtml</a><br><br>---<br></span></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">It is your responsibility to read the documentation and test with your data. Look at the printed output. Maybe, for a point or two, manuall dray a picture.<span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><br><br>---<br></span></span></div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">See attached ...<br><br></span></span></div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">Good Luck<br></span></span><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><br><br></span></span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Nov 8, 2017 at 12:45 PM, Mary Haley <span dir="ltr"><<a href="mailto:haley@ucar.edu" target="_blank">haley@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"><div class="gmail_default" style="font-size:small">Please see our r, theta plotting examples page at:<br></div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/radar.shtml" target="_blank">http://www.ncl.ucar.edu/<wbr>Applications/radar.shtml</a><br></div><div class="gmail_default"><br></div><div class="gmail_default">To be honest, NCL is not tailored for r, theta data, but it *is* possible to plot it. You have to do some of the work to convert to the coordinate system you want.</div><span class="HOEnZb"><font color="#888888"><div class="gmail_default"><br></div><div class="gmail_default">--Mary</div><div class="gmail_default"><br></div></font></span></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 7, 2017 at 7:42 PM, Keren Rosado <span dir="ltr"><<a href="mailto:keren.rosadova@gmail.com" target="_blank">keren.rosadova@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="auto"><br><br><div id="m_4311639732637516052m_2701151468771017766AppleMailSignature">Sent from my iPhone</div><div><br>Begin forwarded message:<br><br></div><blockquote type="cite"><div><b>From:</b> Keren Rosado <<a href="mailto:keren.rosadova@gmail.com" target="_blank">keren.rosadova@gmail.com</a>><br><b>Date:</b> November 7, 2017 at 4:10:01 PM MST<br><b>To:</b> Dennis Shea <<a href="mailto:shea@ucar.edu" target="_blank">shea@ucar.edu</a>><br><b>Subject:</b> <b>Re: [ncl-talk] Fwd: Random file into polar coordinates</b><br><br></div></blockquote><blockquote type="cite"><div><div dir="ltr">I have latitude and longitude in cartesian coordinates (example of the text file is above). That is the only information I have. I plotted the data before using <font face="arial, helvetica, sans-serif"><span style="font-size:12.800000190734863px">gsn_add_polymarker for the domain I want e.g. 15N 20N and 54W-58W. The center of this domain is 16.8N and 56W. What the polymaker function did was if I had an observation at 16N and 53W a black dot was drawn. What I need now is transform that 16N-53W (black dot) into cylindrical coordinates u<wbr>sing as center </span></font><span style="font-family:arial,helvetica,sans-serif;font-size:12.800000190734863px">16.8N and 56W. </span></div><div><div class="m_4311639732637516052h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 7, 2017 at 3:25 PM, 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"><div><div><div><div><div><div><div><div>Again you need clarify even more ...Please look at: <br><br>---<br><br> <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/sphc.html" target="_blank">http://hyperphysics.phy-astr.<wbr>gsu.edu/hbase/sphc.html</a><br></div><br></div>Upper left:<br><br></div>theta is (90-latitude); co-latitude<br></div>phi is longitude<br></div>r is the radius of the earth (assuming a spherical earth)<br><br></div><div>You have all of this information.<br></div><div><br>===<br></div><a href="http://keisan.casio.com/exec/system/1359534351" target="_blank">http://keisan.casio.com/exec/s<wbr>ystem/1359534351</a><br>===<br></div>The radius at any latitude: <br> <a href="http://mathforum.org/library/drmath/view/54158.html" target="_blank">http://mathforum.org/library/d<wbr>rmath/view/54158.html</a><br><br>r(latitude) = r*cos(latitude) ; latitude in radians<br></div><br><div><div><div><br><br></div></div></div></div><div class="m_4311639732637516052m_2701151468771017766HOEnZb"><div class="m_4311639732637516052m_2701151468771017766h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 7, 2017 at 1:07 PM, Keren Rosado <span dir="ltr"><<a href="mailto:keren.rosadova@gmail.com" target="_blank">keren.rosadova@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">R, theta </div><div class="m_4311639732637516052m_2701151468771017766m_-4745623357342057061HOEnZb"><div class="m_4311639732637516052m_2701151468771017766m_-4745623357342057061h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 7, 2017 at 12:11 PM, 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"><div><div>Please clarify your question: <br><br>re: "polar coordinates"<br><br></div>(a) r,theta ? <a href="https://en.wikipedia.org/wiki/Polar_coordinate_system" target="_blank">https://en.wikipedia.org/wiki/<wbr>Polar_coordinate_system</a><br></div>(b) lat,lon ? <br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="m_4311639732637516052m_2701151468771017766m_-4745623357342057061m_-2478670982489959442h5">On Tue, Nov 7, 2017 at 11:52 AM, Keren Rosado <span dir="ltr"><<a href="mailto:keren.rosadova@gmail.com" target="_blank">keren.rosadova@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_4311639732637516052m_2701151468771017766m_-4745623357342057061m_-2478670982489959442h5"><div dir="ltr"><br><div class="gmail_quote"><span style="font-family:arial,helvetica,sans-serif">Hello, </span><br><div dir="ltr"><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">I have a file with observations for the entire globe for one hour period. </font></div><div><div><font face="arial, helvetica, sans-serif" color="#000000">Here are few lines from my txt (observations) files. The highlighted values are for lat and lon: </font></div><div style="font-size:12.800000190734863px"><span style="color:rgb(0,0,0);font-family:Menlo;font-size:11px">2010/08/28,04:00:00.356732, </span><span style="color:rgb(0,0,0);font-family:Menlo;font-size:11px;background-color:rgb(255,255,0)">11<wbr>.7047, 133.9177</span><span style="color:rgb(0,0,0);font-family:Menlo;font-size:11px">, 4.8, 5</span><br></div><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0);min-height:13px">2010/08/28,04:00:00.629722, 36.7353, 52.1856, 26.8, 7<br><span style="font-variant-ligatures:no-common-ligatures"></span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:00.559602, 36.8155, 52.2482, 3.3, 5</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:00.922721, 4.8667, 105.7474, 8.3, 7</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:00.130999, 22.7165,-105.1758, 24.9, 5</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:00.400279, 11.7329, 133.9220, 16.3, 9</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:01.330873, 21.6459,-105.0242, 7.3, 5</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures">2010/08/28,04:00:01.409443, 28.4564, -90.7360, 9.7, 5</span></p><p style="margin:0px;font-stretch:normal;font-size:11px;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-stretch:normal;font-size:11px;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-stretch:normal;line-height:normal"><font face="arial, helvetica, sans-serif"><span style="color:rgb(0,0,0);font-variant-ligatures:no-common-ligatures">I plotted these observations using </span>ncl function gsn_add_polymarker for the domain I am interested in lat and lon. </font></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif"><br></font></span></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif">I will like to now how to transform the lat and lon to polar coordinates for the domain I am interested.</font></span></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif"><br></font></span></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif">Does anyone have an idea of how to to this?</font></span></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif"><br></font></span></p><p style="margin:0px;font-stretch:normal;line-height:normal"><span style="font-size:12.800000190734863px"><font face="arial, helvetica, sans-serif">Thanks! </font></span></p><p style="margin:0px;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span style="font-variant-ligatures:no-common-ligatures"><br></span></p></div></div>
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