[Proj] Using EPSG codes with cs2cs

[Jose Gonçalves]

In addition to my previous e-mail, since you have your own datum shift
parameters it is better to write the full proj string, instead of using an
epsg predefinition. Your rotation angles are in radians but cs2cs expects
arc-seconds. They become 1.04, 0.35, -3.08.
According to the map projection definition you give, the command line
should be something like:

cs2cs +init=epsg:4326 +to +ellps=bessel +proj=tmerc +lon_0=12 +x_0=4500000
+towgs84=582,105,414,1.040,0.350,-3.080,8.3
13.755944 51.054555
4623218.81      5659181.06 -46.16

Regards

Jose'  Gonçalves




2012/5/7 Jose Gonçalves <jagoncal at gmail.com>

> Hi
>
> Are you sure of EPSG code 31495? In my epsg file, installed with proj, I
> can find only:
>
> epsg: 31461    # DHDN / 3-degree Gauss zone 1 (deprecated)
> epsg: 31462    # DHDN / 3-degree Gauss zone 2 (deprecated)
> epsg: 31463    # DHDN / 3-degree Gauss zone 3 (deprecated)
> epsg: 31464    # DHDN / 3-degree Gauss zone 4 (deprecated)
> epsg: 31465    # DHDN / 3-degree Gauss zone 5 (deprecated)
> epsg: 5520      # DHDN / 3-degree Gauss-Kruger zone 1
> epsg: 31466    # DHDN / 3-degree Gauss-Kruger zone 2
> epsg: 31467    # DHDN / 3-degree Gauss-Kruger zone 3
> epsg: 31468    # DHDN / 3-degree Gauss-Kruger zone 4
> epsg: 31469    # DHDN / 3-degree Gauss-Kruger zone 5
>
> If a projection ID is not in the file the expected answer is the one you
> got. It is not a configuration problem.
> Check http://spatialreference.org to check the epsg code
>
> Regards
>
> Jose Gonçalves
>
>
>
>
>
>
> 2012/5/7 rps_rt <ec_eng01 at yahoo.com>
>
>> Dear Warmerdam and all members,
>>
>> I have been browsing and reading for a while to convert my coordinates
>> with
>> no hope until finding this Proj. 4.
>>
>> Kindly, I seek your support here ... I am using Linux Ubuntu to convert
>> from
>> long/lat (WGS84) to Cartesian (x/y) and vice versa. My need here is to get
>> as accurate as possible results (cm-level if possible).
>>
>> I was reading this thread because I had a problem of getting a cs2cs
>> results
>> for espg=31495, while I could get them for espg=31468. But the conversion
>> results with the later one were not accurate ~ almost 100 meters away.
>>
>> e.g.,: echo "13.755944 51.054555" | cs2cs +init=epsg:4326 +to
>> +init=epsg:31468
>>
>> but when I change it to: echo "13.755944 51.054555" | cs2cs
>> +init=epsg:4326
>> +to +init=epsg:31495,
>> I get the message "projection initialization failure cause: no options
>> found
>> in 'init' file".
>>
>> I tried to change something based on this thread, to make sure that my
>> PROJ_LIB path is in place, but it seems I ruined everything. Afterwards,
>> all
>> espg zones gave the below error:
>> "
>> pj_open_lib(epsg): call fopen(/usr/local/bin/cs2cs/epsg) - failed
>> Using from definition: init=epsg:31467
>> Rel. 4.8.0, 6 March 2012
>> <cs2cs>:
>> projection initialization cause: no system list, errno: 20
>> "
>>
>> I tried to "make uninstall" and "make install" but nothing was fixed!!
>>
>> Here are more details about my project:
>>
>> My locations are in Dresden city, Germany, (DHDN4), and I have (I assume)
>> all what is needed to get my coordinates converted accurately, but no idea
>> how to process them in Proj. 4 (I am totally new here):
>>
>> PROJCS["DHDN / Germany zone
>> 4",GEOGCS["DHDN",DATUM["Deutsche_Hauptdreiecksnetz",
>> SPHEROID["Bessel 1841",6377397.155,299.1528128]],PRIMEM["Greenwich",0],
>> UNIT["degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],
>> PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",12],
>> PARAMETER["scale_factor",1],PARAMETER["false_easting",4500000],
>> PARAMETER["false_northing",0],UNIT["metre",1]]
>> TOWGS84=582.0,105.0,414.0,5.042e-6,1.696e-6,-1.4932e-5,8.3
>> EPSG=31495
>>
>> %Seven parameters:
>> % 582.00     - Translation dx in meter to WGS84
>> % 105.0      - Translation dy in meter to WGS84
>> % 414.50     - Translation dz in meter to WGS84
>> % 5.042e-6   - Rotation ro (omega) in Radiant to WGS84
>> % 1.696e-6   - Rotation rf (phi) in radiant to WGS84
>> % -1.4932e-5 - Rotation rk (Kappa) in Radiant to WGS84
>> % 8.3e-06    - Mapscale factor in ppm (parts per million) to WGS84(m)
>>
>> Sorry for the long thread but did not want to miss any details, even in my
>> first ever thread in this forum.
>>
>> I will be looking forward to reading form you.
>> Best regards,
>> Amro
>>
>> --
>> View this message in context:
>> http://osgeo-org.1560.n6.nabble.com/Using-EPSG-codes-with-cs2cs-tp3841592p4957639.html
>> Sent from the PROJ.4 mailing list archive at Nabble.com.
>> _______________________________________________
>> Proj mailing list
>> Proj at lists.maptools.org
>> http://lists.maptools.org/mailman/listinfo/proj
>>
>
>
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