Re[Gvsig_english] projection Roma40-Gauss Boaga to WGS84

[Evemar]

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


Cristina Bedoya wrote:
> 
> Hi Michele,
> 
> The steps you need to do for reprojecting are:
> 
> 1. Open gvSIG and create new View
> 
> 2. Go to the properties of the View and verify that de units of measure 
> and map are in meters and that the current projection is the EPSG:3003 
> (MonteMario/Italyzone1)
> 
> 3. Open the View and add the layer "Iglesias_3003.shp"
> 
> 4. Then, open the geoprocess of reprojection. And complete:
>     - The layer of entry must be: "Iglesias_3003.shp"
>     - Current projection must appear: EPSG:3003
>     - Destination projection you must:
>         - Select RS of the layer type EPSG
>         - Select EPSG: 4326 (WGS84)
>         - Select the EPSG transformation and then select the button below.
>         - Select the transformation with code 1169 or 1662 (Sardinia) 
> and Finish.
> 
> 5. Save the output layer (Iglesias_4326_transf1169.shp) and Accept. (The 
> new layer should not be charged in the same View because it's in a 
> different RS, developers are already aware of this problem to solve in 
> future versions)
> 
> 6. Then creates a new View and open the properties, select EPSG:4326 as 
> a projection of the View.
> 
> 7. Open the View and load the new layer (Iglesias_4326_transf1169.shp) 
> and the comparing layer (Iglesias_4326.shp)
> 
> 8. Using the tool for measuring distances of gvSIG, you'll see that the 
> layers ara far around 5 meters.
> 
> To make sure that the transformation made by gvSIG is correct, we've 
> compared the transformed layer (Iglesias_4326_transf1169.shp) with some 
> WMS services and far around 50 meters.
> 
> Unfortunately we've not found any WFS service in the Sardinia area in 
> EPSG:4326 to compare the results, if you know a WFS service, you might 
> indicate us.
> 
> I hope you solved your problem with this steps, if not, please tell us 
> about what operating system are you working, what version of gvSIG + 
> extensions are you using and if you're comparing the result layer with 
> WFS or WMS service, tell us the URL.
> 
> Greetings,
> 
> Cris
> 
> 
> 
> 
> Michele Beneventi wrote:
>> Hi Cris,
>> first of all thanks for your kind answer.
>> I attach here two layers: one of them is the one in EPSG:3003, while 
>> the other is the one in EPSG:4326 (this second is the comparing 
>> layer). I've found that the reprojection geoprocess makes a mistake of 
>> about 150 meters while using the EPSG transformation coding 1662.
>> Thanks a lot, I'll wait for your answer.
>>
>> Michele
>>
>>   
>>
>> On Tue, Aug 26, 2008 at 2:05 PM, Cristina Bedoya <bedoya_cri at gva.es 
>> <mailto:bedoya_cri at gva.es>> wrote:
>>
>>     Hi Michele,
>>
>>     To help, we need more information, if you want, you can send to us
>>     the layer that you are transformating (RS "Roma40 - Gauss Boaga"
>>     (EPSG: 3003)) and the layer with which you are comparing the data
>>     processed.
>>
>>     Greetings,
>>
>>     Cris
>>
>>
>>
>>
>>     Michele Beneventi wrote:
>>
>>         Hi list,
>>         I have a problem concerning the geoprocess of "reprojection".
>>         I've had to reproject a polygonal layer from the RS "Roma40 -
>>         Gauss Boaga" (EPSG:3003) to the RS "WGS84" (EPSG:4326): for
>>         this I've used the geoprocess of "reprojection" both with the
>>         transformation "Monte Mario to WGS84 (1)" (EPSG: 1169) and
>>         with the transformation "Monte Mario to WGS84 (2)" (EPSG:
>>         1662), which are peculiar for the region of Sardinia.
>>         Unfortunately the results obtained have shown to be quite bad:
>>         actually the mean error is around 90 m. Am I making a mistake
>>         with the settings of the geoprocess, or some other mistake?
>>
>>         Thanks a lot, hope to read from you soon.
>>
>>         -- 
>>         Michele Beneventi
>>
>>        
>> ------------------------------------------------------------------------
>>
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>>
> 
> -- 
> Cristina Bedoya Pellicé
> Proyecto gvSIG
> Conselleria de Infraestructuras y Transportes (GVA).
> Valencia (Spain)
> 
> 
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