<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>The nlat and nlon are dimension names that refer to sizes.This is a "standard grid" [ie: "rectilinear grid"]. In my opinion, this is a <b>poorly structured netCDF file.</b> <br></div><div><br></div><div>--</div><div>%> ncdump -h gpcp_cdr_v23rB1_y2018_m08.nc</div><div>or</div><div>%> ncl_filedump gpcp_cdr_v23rB1_y2018_m08.nc</div><div>--</div><div>dimensions:<br> <b>nlat = 72</b><br> <b>nlon = 144</b><br> t<b>ime = 1</b></div><div>...</div><div> float <b>time(time)</b><br></div><div> float <b>latitude(nlat)</b></div><div><b> </b>float<b> longitude(nlon)</b></div><div><b> </b>float <b>precip(nlat,nlon)</b><br></div><div>-------------------------------</div><div>What is really desired is<br></div><div><br></div><div><div> float <b>latitude(latitude)</b></div><div><b> </b>float<b> longitude(longitude)</b></div><div><b> </b>float <b>precip(latitude,longitude) </b>or, better<b> <b>precip(time,latitude,longitude) <br></b></b></div><div><b><b><br></b></b></div></div><div>Variables structured like <b>latitude(latitude) are </b>called <b> "<a href="https://www.unidata.ucar.edu/software/netcdf/workshops/2011/datamodels/NcCVars.html" target="_blank">coordinate variables</a>". </b>Please read.<br><b></b></div><div><br></div><div>-----------------------------</div><div><br> latitude = f->latitude ; latitude(nlat)<br> latitude!0 = "latitude" ; "nlat" ==> "latitude"<br> latitude&latitude= latitude ; assign coordinate latitude values<br> printVarSummary(latitude) ; latitude(latitude)<br><br> longitude = f->longitude ; longitude(nlon)<br> longitude!0 = "longitude" ; "nlon" ==> "longitude"<br> longitude&longitude= longitude ; assign coordinate longitude values<br> printVarSummary(longitude) ; longitude(longitude)<br><br> precip = f->precip ; precip(nlat,nlon) ; (0,1)<br> precip!0 = "latitude" ; name dimensions<br> precip!1 = "longitude"<br> precip&latitude = latitude ; assign values to named dimension<br> precip&longitude = longitude<br> printVarSummary(precip)<br><br></div></div></div></div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail_attr">On Sun, Jan 27, 2019 at 7:09 AM Barry Lynn <<a href="mailto:barry.h.lynn@gmail.com" target="_blank">barry.h.lynn@gmail.com</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">Hello:<div><br></div><div>I believe that this is a standard grid. Latitude(nlat) just means that the variable name is latitude and there are nlat points.</div><div><br></div><div>It can be useful to use ncl and use PrintVarSummary after extracting the variable you want to look at from the file. </div><div><br></div><div>For example:</div><div><br></div><div>
<p class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:21px;line-height:normal;font-family:"Courier New";color:rgb(0,0,0)"><span class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-s1" style="font-variant-ligatures:no-common-ligatures">lon = a</span><span class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-s2" style="font-variant-ligatures:no-common-ligatures;background-color:rgb(224,228,9)">-></span><span class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-s1" style="font-variant-ligatures:no-common-ligatures">longitude</span></p><p class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:21px;line-height:normal;font-family:"Courier New";color:rgb(0,0,0)"><span class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail-s1" style="font-variant-ligatures:no-common-ligatures">printVarSummary(lon)</span></p></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail_attr">On Sun, Jan 27, 2019 at 3:39 PM victor <<a href="mailto:mashibo321@126.com" target="_blank">mashibo321@126.com</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 style="line-height:1.7;color:rgb(0,0,0);font-size:14px;font-family:Arial"><div>I need some help with GPCP monthly data grid.</div><div>The grid of data seems unusual. When I do ncdump -h, it output like below. I don't know how to deal with something like "latitude(nlat)"?</div><div>Should I need to regriding? What should I do if I want to reshape the data to an usual one?<br></div><div>...</div>variables:<br> float latitude(nlat) ;<br> latitude:long_name = "Latitude" ;<br> latitude:standard_name = "latitude" ;<br> latitude:units = "degrees_north" ;<br> latitude:valid_range = -90.f, 90.f ;<br> latitude:missing_value = -9999.f ;<br> latitude:bounds = "lat_bounds" ;<br> float longitude(nlon) ;<br> longitude:long_name = "Longitude" ;<br> longitude:standard_name = "longitude" ;<br> longitude:units = "degrees_east" ;<br> longitude:valid_range = 0.f, 360.f ;<br> longitude:missing_value = -9999.f ;<br> longitude:bounds = "lon_bounds" ;<br> float time(time) ;<br> time:long_name = "time" ;<br> time:standard_name = "time" ;<br> time:units = "days since 1970-01-01 00:00:00 0:00" ;<br> time:calendar = "julian" ;<br> time:axis = "T" ;<br> float lat_bounds(nlat, nv) ;<br> lat_bounds:units = "degrees_north" ;<br> lat_bounds:comment = "latitude values at the north and south bounds of each pixel." ;<br> float lon_bounds(nlon, nv) ;<br> lon_bounds:units = "degrees_east" ;<br> lon_bounds:comment = "longitude values at the west and east bounds of each pixel." ;<br> float time_bounds(nv, time) ;<br> time_bounds:units = "days since 1970-01-01 00:00:00 0:00" ;<br> time_bounds:comment = "time bounds for each time value" ;<br> float precip(nlat, nlon) ;<br> precip:long_name = "NOAA Climate Data Record (CDR) of Monthly GPCP Satellite-Gauge Combined Precipitation" ;<br> precip:standard_name = "precipitation amount" ;<br> precip:units = "millimeters/day" ;<br> precip:coordinates = "longitude latitude time" ;<br> precip:valid_range = 0.f, 100.f ;<br> precip:cell_methods = "precip: mean" ;<br> precip:missing_value = -9999.f ;<br> float precip_error(nlat, nlon) ;<br> precip_error:long_name = "NOAA CDR of GPCP Satellite-Gauge Combined Precipitation Error" ;<br> precip_error:units = "millimeters/day" ;<br> precip_error:coordinates = "longitude latitude" ;<br> precip_error:valid_range = 0.f, 100.f ;<br><div> precip_error:missing_value = -9999.f ;</div><div>...</div><div><br></div><div><br></div><br><br><br><br><div>--<br><div style="font-family:Helvetica,"Microsoft Yahei",verdana">------------------------------------------------------------------------</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">Shibo Ma(马世波)</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">Graduate Student</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">Department of Atmospheric and Oceanic Sciences</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">School of Physics, Peking University</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">No. 209 Chengfu Road, Beijing, China</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">Email: <a href="mailto:mashibo321@126.com" target="_blank">mashibo321@126.com</a></div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">Tel : +86 18810507714</div><div style="font-family:Helvetica,"Microsoft Yahei",verdana">------------------------------------------------------------------------</div><div><br></div><div style="clear:both"></div></div></div><br><br><span title="neteasefooter"><p> </p></span>_______________________________________________<br>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail-m_21929950208814994gmail-m_8014679407323525409gmail-m_3652719799491368154gmail_signature"><div dir="ltr"><div><div dir="ltr">Barry H. Lynn, Ph.D<div><div>Senior Associate Scientist, Lecturer,</div><div><div><span style="color:rgb(136,136,136)">The Institute of the Earth Science, </span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">The Hebrew University of Jerusalem, </span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">Givat Ram, Jerusalem 91904, Israel </span><br style="color:rgb(136,136,136)"></div><span style="color:rgb(136,136,136)">Tel: 972 547 231 170</span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">Fax: (972)-25662581</span></div></div><div><span style="color:rgb(136,136,136)"><br></span></div><div>C.E.O, Weather It Is, LTD<br>Weather and Climate Focus<br><a href="http://weather-it-is.com" target="_blank">http://weather-it-is.com</a><br>Jerusalem, Israel<br>Local: 02 930 9525<br>Cell: 054 7 231 170<br>Int-IS: x972 2 930 9525<br><br></div></div></div></div></div></div>
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