Margherita Di Leo | 17 Dec 14:34 2014

convert latlon to UTM without knowing the zone beforehand


I need to convert any pairs of geographic coordinates (latlon) into UTM. This needs to run automatically so that I need an automatic tool to tell for any pairs which UTM zone it belongs to before converting. Of course I can encode in my script all possible cases, but before reinventing the wheel i wanted to ask if there is such tool already within proj.4 library.

Thank you in advance

Best regards,

Dr. Margherita DI LEO    
Scientific / technical project officer

European Commission - DG JRC 
Institute for Environment and Sustainability (IES)
Via Fermi, 2749
I-21027 Ispra (VA) - Italy - TP 261
Tel. +39 0332 78 3600   

Disclaimer: The views expressed are purely those of the writer and may not in any circumstance be regarded as stating an official position of the European Commission.
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Charles Karney | 16 Dec 14:14 2014

The area of a rhumb line polygon

The calculation of the area of a geodesic polygon has been included in
GeographicLib since v1.4 (2010-09).

In the latest version v1.39, I've also included the equivalent
calculation when the edges of the polygon are rhumb lines.  The
formulation is given in

and the online planimeter

implements this area calculation.  I've also worked out the area when
the edges are great ellipses.  For the formulation, see

An implementation is included in the Matlab package

Comments are welcome.

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SriRam Prasad Bhasker | 14 Nov 07:24 2014

Build GDAL with NADSHIFT's


I have a below .prj file


GEOGCS["GCS_NAD_1983_2011",DATUM["D_NAD_1983_2011",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433],METADATA["USA - CONUS and Alaska; PRVI",167.65,14.93,-63.89,74.71,0.0,0.0174532925199433,0.0,1511]]


Can someone guide me how to project a Shape file with the below prj File.

Testepsg is giving a failure for the above prj file.


Let me know if anyone has used this earlier… To use the Conus and Alaska Parameters

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Jeff McKenna | 13 Nov 13:14 2014

Re: PROJ 4.9.0RC1

I may have missed the public message, but in case others did as well:
there is an RC2 also available for testing:


Jeff McKenna
MapServer Consulting and Training Services

On 2014-09-13 8:33 PM, Frank Warmerdam wrote:
> Folks,
> I have discovered that PROJ.4 was left with a hanging beta
> again some time ago without my following up on the release.
> Grr, I'm lame!  Anyways, Howard Butler and I have made a
> pass through open bugs and fixed some.  Howard has also
> introduced CMake support for PROJ.4 (though the automake
> way is also still supported).
> Source is at:
> I would appreciate feedback before finalizing the release in the coming
> week.
> Best regards,
> Frank

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Shimi Chen | 5 Nov 10:47 2014

cs2cs produces partial output when called from matlab


I realize that MATLAB is proprietary software and thus not very reproducible.
However I would appreciate if someone could think if he has an idea why this could happen.
I will explain the issue with a simple example.
I made a file 0.tmp with the contents:

35.049 31.728
Running this command:
cs2cs +init=epsg:4326 +to +init=epsg:2039 <0.tmp >1.tmp Produces this correct 1.tmp file:
204718.31 626160.79 -20.79 However, when calling the exact same command from the matlab shell:
system(['cs2cs +init=epsg:4326 +to +init=epsg:2039 <0.tmp >1.tmp']) The resulting file 1.tmp only has these contents:
-20.787 So, clearly, cs2cs is getting all of the input, since otherwise it could not get the -20.79 right. The question is why would it not also write 204718.31    626160.79  to the file?
What weird thing could MATLAB be doing with the input that would make cs2cs produce this partial output?

Note: do not try to reproduce in Octave. It works fine in Octave.

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Zhang Qun | 25 Oct 08:46 2014

the x, and y meaning in pj_transform

Dear all

I have got a small question that I can not find the confirmed answer on the web. I am now using pj_transform to transform coordinates from svy21 to latlon using the following code snippet:

pj_svy21 = pj_init_plus("+proj=tmerc +lat_0=1.366666666666667 +lon_0=103.8333333333333 +k=1 +x_0=28001.642 +y_0=38744.572 +ellps=WGS84 +units=m +no_defs")
pj_latlong = pj_init_plus("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")

double svy_east = 12056.915;
double svy_north = 37621.665;
double lat_radian = svy_east;
double lon_radian = svy_north;
projResult = pj_transform(pj_svy21, pj_latlong, 1, 0, &lat_radian, &lon_radian, NULL );

But the result (lat_radian, lon_radian) I got is reversed, i.e. the result given by
pj_transform(pj_svy21, pj_latlong, 1, 0, &x, &y, NULL )

is x corresponds to longitude and y corresponds to latitude. It is not the other way around as I did.

Is this the way it worked or I just used this function wrongly? Thanks.

Best regards,
Zhang Qun
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Artur Bercik | 24 Oct 08:26 2014

(no subject)

Dear Proj list members:

Being a very new in this field, could someone answer me about the following problem:

I have a pair of Geodetic Latitude and Geodetic Longitude (50.89524, 117.69043).
How can I convert it into Latitude and Longitude with WGS84 Ellepsoid?

Thanks in the advance.

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Charles Clercq | 23 Oct 10:13 2014

Convertion Lat/Long WGS84 -> UTM-WGS84 problem?

Dear all,

I have written a simple basic code inspired from the doc to convert data in lat/long WGS84 in meters (UTM/WGS84)
My problem is that when I tested it with lat: 51.0242 / long: 3.96338 and obtained  x: 7627600.282316 / y: 742130.588781 which I compared with online converter which gave me : 5652958 / 567564

I would like to understand the error. I that because proj can't convert from WGS84 lat/long to UTM WGS84 ?

I tested with command line:
echo 51.0242 3.96338 | cs2cs.exe +proj=latlong +ellps=WGS84 +to +proj=utm +ellps=WGS84 +datum=WGS84 +units=m
and obtained the exact same result.

Any advice?



The code
#include <iostream>

#include <proj_api.h>

int _tmain(int argc, _TCHAR* argv[])
projPJ pj_merc, pj_latlong;
    double x, y;

    if (!(pj_merc = pj_init_plus("+proj=utm +ellps=WGS84 +datum=WGS84 +units=m")) )
    if (!(pj_latlong = pj_init_plus("+proj=latlong +ellps=WGS84")) )
std::cout << "Lat: ";
double latitude;
std::cin >> latitude;
std::cout << std::endl;
std::cout << "Long: ";
double longitude;
std::cin >> longitude;

    x = latitude*DEG_TO_RAD;
y = longitude*DEG_TO_RAD;

    int p = pj_transform(pj_latlong, pj_merc, 1, 1, &x, &y, NULL );

//std::cout << "The coordinate in meters are: " << x << "/" << y << std::endl;
printf("Lat/Long: %f/%f - in meters ->: %f/%f\n", latitude, longitude, x, y);

return 0;
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Mikael Rittri | 22 Oct 11:34 2014

Map projection used for CADRG polar areas?


I am reading the specification for CADRG, .

But I am confused about the polar areas.


Section 3.5.5 says: “CADRG shall use a polar stereographic projection“.


And Section 3.5.6 says “Polar frames are defined in polar stereographic

projection and non-polar frames are in the ARC projection.


But Section 3.6.2 says: “Pixel coordinates in the polar zones are

proportional to rectangular coordinates of the Azimuthal

Equidistant projection, polar aspect, spherical form (as

defined in Map Projections–A Working Manual, page 191).


And section 30.1 says: “Polar zone equations are based on

the Azimuthal Equidistant projection, polar aspect,

spherical form.


Since Polar Stereographic is not the same thing as Azimuthal Equidistant

in polar aspect, I assume that one of the two alternatives is just a typo

(unless I am missing something). But which one is the typo of  

“Stereographic” and “Azimuthal Equidistant”? Does anyone know?


Best regards,


Mikael Rittri





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Olivier PENA | 21 Oct 11:34 2014

pj_set_searchpath support for wince


Small patchs are attached in order to have minimal support for opening files under wince using pj_set_searchpath.

I hope I’m in the right place to send this patch.

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Ed Weber | 29 Sep 18:43 2014

spamming the wiki

Hi Proj4 list,
There is a problem with the Proj4 wiki. A user named "domtheos" has been
editing pages and adding completely unrelated links (maybe the
account has been hacked?).  I changed all pages back to there correct form
a few days ago but domtheos has done it again. I looked around the Proj4
web site but I don't see a place to report problems.  Could someone advise
about how to report the problem and flag the account (or let the
user know there is a problem)?

Thanks for your help,
Ed Weber

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