[Gvsig_english] Problem in WGS 84 to UTM SAD 69 transformation

[Javier Galán]

Hi Evermar,

Seeing the parameters I realized that it not the same definition for the 
epsg and esri library.
The both, in epsg library, that has the same definition as you wrote are 
29172/29192. I'm not sure if there's any difference between them, but i 
didn't see any.

May be that solve the problem.

Regards


Evemar Wernick escribió:
> Javier,
>
> Thanks for your answer. I didn't have noticed that using EPSG I could 
> set up transformations.
>
> Unfortunately, it didn't work. I tried to use the 3 transformations 
> avaliable to Brasil (1, 4 and 14), and tried also manually set up the 
> parameters (to transformation (14): X= -66.87, Y= 4.37, Z= -38.52) 
> without success (all the result files are always in the same position).
>
> I'm sending anexed the files used for the test and the results, and 
> below the process conversion that I've tried (works in ArcGIS and not 
> in gvSIG).
>
> *** Start ArcGIS process conversion ****
>
> In ArcGIS, I used the ArcToolBox’s Project tool:
>
> - Input Dataset or Feature Class: barracao_original_gps_wgs84.shp
>
> - Input Coordinate System (optional): GCS_WGS_1984  (code:4326)
>
> /Angular Unit: Degree (0,017453292519943299)
> Prime Meridian: Greenwich (0,000000000000000000)
> Datum: D_WGS_1984
>   Spheroid: WGS_1984
>     Semimajor Axis: 6378137,000000000000000000
>     Semiminor Axis: 6356752,314245179300000000
>     Inverse Flattening: 298,257223563000030000/
>
> - Output Dataset or Feature Class: barracao_ArcGIS_SAD69_Project14.shp
>
> - Output Coordinate System: SAD_1969_UTM_Zone_22S  (code:29182)
>
> /Projection: Transverse_Mercator
> False_Easting: 500000,000000
> False_Northing: 10000000,000000
> Central_Meridian: -51,000000
> Scale_Factor: 0,999600
> Latitude_Of_Origin: 0,000000
> Linear Unit: Meter (1,000000)
>
> Geographic Coordinate System: GCS_South_American_1969
> Angular Unit: Degree (0,017453292519943299)
> Prime Meridian: Greenwich (0,000000000000000000)
> Datum: D_South_American_1969
>   Spheroid: GRS_1967_Truncated
>     Semimajor Axis: 6378160,000000000000000000
>     Semiminor Axis: 6356774,719195305400000000
>     Inverse Flattening: 298,250000000000000000/
>
> - Geographic Transformation (optional): SAD_1969_To_WGS_1984_14  
> (code:1548)
>
> /GEOGTRAN["SAD_1969_To_WGS_1984_14",GEOGCS["GCS_South_American_1969",DATUM["D_South_American_1969",SPHEROID["GRS_1967_Truncated",6378160.0,298.25]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHOD["Geocentric_Translation"],PARAMETER["X_Axis_Translation",-66.87],PARAMETER["Y_Axis_Translation",4.37],PARAMETER["Z_Axis_Translation",-38.52]]
> /
> *** End ArcGIS process conversion ****
>
>
> *** Start gvSIG process conversion ****
>
> In gvSIG, I used Geoprocess toolbox’s Reproject:
>
> - Input Cover: barracao_original_gps_wgs84.shp
>
> - Source Projection: EPSG: 4326
>
> - Target Projection: EPSG: 29182
>
> - Select Transformation: EPSG transformation
>
> <Next>
>
> - Transformation code: 1548 SAD69 to WGS 84 (14)
>
> - Output Cover: barracao_gvSIG_SAD69_Project14.shp
>
> *** End gvSIG process conversion ****
>
>
> Please help. We are planning to use gvSIG in many governamental 
> projects and this conversion is fundamental.
>
> Thanks in advance,
>
> Evemar Wernick
> Brasil
> evemar at paranacidade.org.br
>
>
>
> Javier Galán escreveu:
>> Dear Eveman,
>>
>> That happens because gvSIG don have a library to do transformation 
>> between ESRI definitions.
>> What you can do is put the view an data whit an EPSG definition, (I 
>> checked that the code is the same)
>> and then you can choose the EPSG transformation that better fits to 
>> your data.
>>
>> Regards
>>
>> Evemar escribió:
>>> Hi,
>>>
>>> I'm facing a similar problem:
>>>
>>> I received some gps data in WGS 84 (ESRI:4326) coordinate system.
>>> When I reproject it to SAD 1969 UTM zone 22S (ESRI:29182) using 
>>> gvSIG, it
>>> doesn't fit correctly (difference ~100m)
>>>
>>> When I do the same using ESRI ArcCatalog, using the same parameters 
>>> except
>>> the "Geographic Transformation" (where I can choose 
>>> SAD_1969_To_WGS_1984_14
>>> - ESRI:1548), it fits nice.
>>>
>>> Someone knows how can I set those transformation parameters in 
>>> gvSIG? Is it
>>> possible?
>>>
>>> Thanks,
>>> Evemar
>>> Brasil
>>>
>>
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-- 
Javier Galán Sánchez
Proyecto gvSIG
Consellería de Infraestructuras y Transportes (GVA)
Valencia (España)