[Matplotlib-users] basemap UTM conversion discrepancy

 [Matplotlib-users] basemap UTM conversion discrepancy From: Stefan Mertl - 2011-12-19 21:23:44 Attachments: signature.asc ```Hello, I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do lon/lat to UTM coordinate conversion. I did some tests and noticed that there is a discrepancy between the mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool output. e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM coordinates UTM zone 33 with WGS84 ellipse. I'm using the following proj4 string for the conversion: +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs The output using mpl_toolkits.basemap.pyproj.Proj is: x: 611458.865; y: 5339596.032 The proj commandline tool using the same proj4 string gives: x: 611458.69 y: 5339617.54 As you can see, the y coordinate differs significantly. Here's the code used with the basemap pyproy classes: -------------------------------------------------- from mpl_toolkits.basemap.pyproj import Proj # I got the proj string from # http://spatialreference.org/ref/epsg/32633 myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs") lat = 48.2 lon = 16.5 (x,y) = myProj(lon, lat) print "x: %.3f; y: %.3f" % (x,y) --------------------------------------------------- Can somebody explain me this behavior? Regards, Stefan. ```

 [Matplotlib-users] basemap UTM conversion discrepancy From: Stefan Mertl - 2011-12-19 21:23:44 Attachments: signature.asc ```Hello, I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do lon/lat to UTM coordinate conversion. I did some tests and noticed that there is a discrepancy between the mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool output. e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM coordinates UTM zone 33 with WGS84 ellipse. I'm using the following proj4 string for the conversion: +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs The output using mpl_toolkits.basemap.pyproj.Proj is: x: 611458.865; y: 5339596.032 The proj commandline tool using the same proj4 string gives: x: 611458.69 y: 5339617.54 As you can see, the y coordinate differs significantly. Here's the code used with the basemap pyproy classes: -------------------------------------------------- from mpl_toolkits.basemap.pyproj import Proj # I got the proj string from # http://spatialreference.org/ref/epsg/32633 myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs") lat = 48.2 lon = 16.5 (x,y) = myProj(lon, lat) print "x: %.3f; y: %.3f" % (x,y) --------------------------------------------------- Can somebody explain me this behavior? Regards, Stefan. ```
 Re: [Matplotlib-users] basemap UTM conversion discrepancy From: Jeff Whitaker - 2011-12-19 23:21:17 ```On 12/19/11 2:23 PM, Stefan Mertl wrote: > Hello, > > I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do > lon/lat to UTM coordinate conversion. > I did some tests and noticed that there is a discrepancy between the > mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool > output. > > e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM > coordinates UTM zone 33 with WGS84 ellipse. > I'm using the following proj4 string for the conversion: > +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs > > The output using mpl_toolkits.basemap.pyproj.Proj is: > x: 611458.865; y: 5339596.032 > > The proj commandline tool using the same proj4 string gives: > x: 611458.69 y: 5339617.54 > > As you can see, the y coordinate differs significantly. > > Here's the code used with the basemap pyproy classes: > > -------------------------------------------------- > > from mpl_toolkits.basemap.pyproj import Proj > > # I got the proj string from > # http://spatialreference.org/ref/epsg/32633 > myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m > +no_defs") > > lat = 48.2 > lon = 16.5 > > (x,y) = myProj(lon, lat) > > print "x: %.3f; y: %.3f" % (x,y) > > --------------------------------------------------- > > Can somebody explain me this behavior? > > Regards, > Stefan. > Stefan: When I run this test, I get the same answer with both, and it is the same as the answer basemap.pyproj gave you. I suspect you didn't install the extra datum files with your command-line proj distribution. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX : (303)497-6449 NOAA/OAR/PSD R/PSD1 Email : Jeffrey.S.Whitaker@... 325 Broadway Office : Skaggs Research Cntr 1D-113 Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg ```
 Re: [Matplotlib-users] basemap UTM conversion discrepancy From: Stefan Mertl - 2011-12-19 23:47:23 Attachments: signature.asc ```Hi Jeff, I'm not an expert in coordinate transformation and the usage of proj, so I can't exactly tell you if I have all the datum files installed. If you could tell me what files could be missing I could search for them. What makes me wonder, is that you get the results that my mpl_toolkits.basemap.pyproj.Proj usage produced. When using some conversion tools on the internet like http://home.hiwaay.net/~taylorc/toolbox/geodesy/datumtrans/ or http://www.uwgb.edu/dutchs/UsefulData/ConvertUTMNoOZ.HTM I get the results that my commandline proj produces. So I think that something with my pyproj installation is not working. Regards, Stefan. Am Montag, den 19.12.2011, 15:51 -0700 schrieb Jeff Whitaker: > On 12/19/11 2:23 PM, Stefan Mertl wrote: > > Hello, > > > > I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do > > lon/lat to UTM coordinate conversion. > > I did some tests and noticed that there is a discrepancy between the > > mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool > > output. > > > > e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM > > coordinates UTM zone 33 with WGS84 ellipse. > > I'm using the following proj4 string for the conversion: > > +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs > > > > The output using mpl_toolkits.basemap.pyproj.Proj is: > > x: 611458.865; y: 5339596.032 > > > > The proj commandline tool using the same proj4 string gives: > > x: 611458.69 y: 5339617.54 > > > > As you can see, the y coordinate differs significantly. > > > > Here's the code used with the basemap pyproy classes: > > > > -------------------------------------------------- > > > > from mpl_toolkits.basemap.pyproj import Proj > > > > # I got the proj string from > > # http://spatialreference.org/ref/epsg/32633 > > myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m > > +no_defs") > > > > lat = 48.2 > > lon = 16.5 > > > > (x,y) = myProj(lon, lat) > > > > print "x: %.3f; y: %.3f" % (x,y) > > > > --------------------------------------------------- > > > > Can somebody explain me this behavior? > > > > Regards, > > Stefan. > > > Stefan: > > When I run this test, I get the same answer with both, and it is the > same as the answer basemap.pyproj gave you. I suspect you didn't > install the extra datum files with your command-line proj distribution. > > -Jeff > ```
 Re: [Matplotlib-users] basemap UTM conversion discrepancy From: Jeff Whitaker - 2011-12-20 01:33:19 Attachments: Message as HTML ```On 12/19/11 4:47 PM, Stefan Mertl wrote: > Hi Jeff, > > I'm not an expert in coordinate transformation and the usage of proj, so > I can't exactly tell you if I have all the datum files installed. If you > could tell me what files could be missing I could search for them. > > What makes me wonder, is that you get the results that my > mpl_toolkits.basemap.pyproj.Proj usage produced. When using some > conversion tools on the internet like > http://home.hiwaay.net/~taylorc/toolbox/geodesy/datumtrans/ or > http://www.uwgb.edu/dutchs/UsefulData/ConvertUTMNoOZ.HTM > I get the results that my commandline proj produces. > So I think that something with my pyproj installation is not working. > > Regards, > Stefan. Stefan: I mis-spoke in my earlier email - the answer I get with pyproj is the same as you get with command line proj. What version of basemap do you have installed? -Jeff > > Am Montag, den 19.12.2011, 15:51 -0700 schrieb Jeff Whitaker: >> On 12/19/11 2:23 PM, Stefan Mertl wrote: >>> Hello, >>> >>> I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do >>> lon/lat to UTM coordinate conversion. >>> I did some tests and noticed that there is a discrepancy between the >>> mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool >>> output. >>> >>> e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM >>> coordinates UTM zone 33 with WGS84 ellipse. >>> I'm using the following proj4 string for the conversion: >>> +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs >>> >>> The output using mpl_toolkits.basemap.pyproj.Proj is: >>> x: 611458.865; y: 5339596.032 >>> >>> The proj commandline tool using the same proj4 string gives: >>> x: 611458.69 y: 5339617.54 >>> >>> As you can see, the y coordinate differs significantly. >>> >>> Here's the code used with the basemap pyproy classes: >>> >>> -------------------------------------------------- >>> >>> from mpl_toolkits.basemap.pyproj import Proj >>> >>> # I got the proj string from >>> # http://spatialreference.org/ref/epsg/32633 >>> myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m >>> +no_defs") >>> >>> lat = 48.2 >>> lon = 16.5 >>> >>> (x,y) = myProj(lon, lat) >>> >>> print "x: %.3f; y: %.3f" % (x,y) >>> >>> --------------------------------------------------- >>> >>> Can somebody explain me this behavior? >>> >>> Regards, >>> Stefan. >>> >> Stefan: >> >> When I run this test, I get the same answer with both, and it is the >> same as the answer basemap.pyproj gave you. I suspect you didn't >> install the extra datum files with your command-line proj distribution. >> >> -Jeff >> >> >> >> ------------------------------------------------------------------------------ >> Write once. Port to many. >> Get the SDK and tools to simplify cross-platform app development. Create >> new or port existing apps to sell to consumers worldwide. Explore the >> Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join >> http://p.sf.net/sfu/intel-appdev >> >> >> _______________________________________________ >> Matplotlib-users mailing list >> Matplotlib-users@... >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users ```
 Re: [Matplotlib-users] basemap UTM conversion discrepancy From: Stefan Mertl - 2011-12-20 20:19:15 Attachments: signature.asc ```Jeff, Here are the versions that I'm working with: basemap: 1.0.2 matplotlib: 1.1.0 numpy: 1.5.1 libgeos: 3.2.0 I ran the coordinate conversion on another computer with the same system configuration and there it works as it should. I have tried to clean my system and removed all the packages related to basemap (geos, proj) and only reinstalled the required libgeos packages. I deleted the basemap directory from the /usr/local/lib/python2.7/dist-packages. I deleted the _geoslib.so from /usr/local/lib/python2.7/dist-packages. After that I rebuilt and installed basemap. The problem still remains. Don't know what's going wrong. Stefan. Am Montag, den 19.12.2011, 18:33 -0700 schrieb Jeff Whitaker: > On 12/19/11 4:47 PM, Stefan Mertl wrote: > > Hi Jeff, > > > > I'm not an expert in coordinate transformation and the usage of proj, so > > I can't exactly tell you if I have all the datum files installed. If you > > could tell me what files could be missing I could search for them. > > > > What makes me wonder, is that you get the results that my > > mpl_toolkits.basemap.pyproj.Proj usage produced. When using some > > conversion tools on the internet like > > http://home.hiwaay.net/~taylorc/toolbox/geodesy/datumtrans/ or > > http://www.uwgb.edu/dutchs/UsefulData/ConvertUTMNoOZ.HTM > > I get the results that my commandline proj produces. > > So I think that something with my pyproj installation is not working. > > > > Regards, > > Stefan. > > Stefan: I mis-spoke in my earlier email - the answer I get with pyproj > is the same as you get with command line proj. What version of > basemap do you have installed? > > -Jeff > > > > Am Montag, den 19.12.2011, 15:51 -0700 schrieb Jeff Whitaker: > > > On 12/19/11 2:23 PM, Stefan Mertl wrote: > > > > Hello, > > > > > > > > I'm starting to use the mpl_toolkits.basemap.pyproj.Proj class to do > > > > lon/lat to UTM coordinate conversion. > > > > I did some tests and noticed that there is a discrepancy between the > > > > mpl_toolkits.basemap.pyproj.Proj output and the proj commandline tool > > > > output. > > > > > > > > e.g.: I'm converting the coordinates lat=48.2; lon=16.5 to UTM > > > > coordinates UTM zone 33 with WGS84 ellipse. > > > > I'm using the following proj4 string for the conversion: > > > > +proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs > > > > > > > > The output using mpl_toolkits.basemap.pyproj.Proj is: > > > > x: 611458.865; y: 5339596.032 > > > > > > > > The proj commandline tool using the same proj4 string gives: > > > > x: 611458.69 y: 5339617.54 > > > > > > > > As you can see, the y coordinate differs significantly. > > > > > > > > Here's the code used with the basemap pyproy classes: > > > > > > > > -------------------------------------------------- > > > > > > > > from mpl_toolkits.basemap.pyproj import Proj > > > > > > > > # I got the proj string from > > > > # http://spatialreference.org/ref/epsg/32633 > > > > myProj = Proj("+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m > > > > +no_defs") > > > > > > > > lat = 48.2 > > > > lon = 16.5 > > > > > > > > (x,y) = myProj(lon, lat) > > > > > > > > print "x: %.3f; y: %.3f" % (x,y) > > > > > > > > --------------------------------------------------- > > > > > > > > Can somebody explain me this behavior? > > > > > > > > Regards, > > > > Stefan. > > > > > > > Stefan: > > > > > > When I run this test, I get the same answer with both, and it is the > > > same as the answer basemap.pyproj gave you. I suspect you didn't > > > install the extra datum files with your command-line proj distribution. > > > > > > -Jeff > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > Write once. Port to many. > > > Get the SDK and tools to simplify cross-platform app development. Create > > > new or port existing apps to sell to consumers worldwide. Explore the > > > Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join > > > http://p.sf.net/sfu/intel-appdev > > > > > > > > > _______________________________________________ > > > Matplotlib-users mailing list > > > Matplotlib-users@... > > > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ```