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

[Evemar Wernick]

Hi, Javier.

Thanks again for your help and patience...
I've tried both 29172 and 29192 (for 1, 4, 14 epsg transformation, and 
no transformation), but it doesn't work.
The EPSG:29172 doesn't fit.
The EPSG 29182/29192 have precisions about 80-100 meters.
It's very strange because I compared the results of transformation from 
EPSG:4326 to:
- barracao_EPSG_4326_29182_1.shp
- barracao_EPSG_4326_29182_4.shp
- barracao_EPSG_4326_29182_14.shp
- barracao_EPSG_4326_29182_no_transformation.shp
- barracao_EPSG_4326_29192_1.shp
- barracao_EPSG_4326_29192_4.shp
- barracao_EPSG_4326_29192_14.shp
- barracao_EPSG_4326_29192_no_transformation.shp
and all of them are in the same position (without any displacement).

I think gvSIG isn't using parameters in transformation...

By the way, how did you find the definition and paramenters of the EPSG 
codes?

Thanks,
Evemar


Javier Galán escreveu:
> 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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