Hello, I am facing some difficulties with the projection trasform from ETRS89 / ETRS-LAEA to UTM33WGS84. There is anybody which has the same problem, or someone who can help me,please? thank you Anna
Hello, I am facing some difficulties with the projection trasform from ETRS89 / ETRS-LAEA to UTM33WGS84. There is anybody which has the same problem, or someone who can help me,please? thank you Anna
Hi Anna,
What kind of difficulties are you having? Is the data vector or raster (if raster, what format?)? What ArcGIS version are you using? Some LAEA data uses a sphere rather than an ellipsoid/spheroid which if the metadata isn't correct can cause problems when the data is reprojected.
Same here: ArcGIS does not project correctly between ETRS-LAEA and WGS84 ArcGIS Desktop (ArcView) 9.3.1 SP1, on Windows Vista
To verify the problem: go to http://www.eea.europa.eu/data-and-maps/data/urban-atlas and download the file it010l_catania.zip. This covers the town of Catania in Sicily, Italy, at aprox. 15.1E / 37.5N The data comes in an Lambert Azimuthal Equal Area projection on ETRS89. I project this into WGS84, using the ArcGIS project tool. The process succeeds without error or warnings. However, the result lies at about 4.2E / 14.4S. This is definitely wrong.
I also project the dataset into WGS84, using QuantumGIS. The result lies at about 15.1E / 37.5N. This is correct.
I submitted this as a support case to our local distributor, ESRI UK. Will post solution.
Same here: ArcGIS does not project correctly between ETRS-LAEA and WGS84 ArcGIS Desktop (ArcView) 9.3.1 SP1, on Windows Vista
To verify the problem: go to http://www.eea.europa.eu/data-and-maps/data/urban-atlas and download the file it010l_catania.zip. This covers the town of Catania in Sicily, Italy, at aprox. 15.1E / 37.5N The data comes in an Lambert Azimuthal Equal Area projection on ETRS89. I project this into WGS84, using the ArcGIS project tool. The process succeeds without error or warnings. However, the result lies at about 4.2E / 14.4S. This is definitely wrong.
I also project the dataset into WGS84, using QuantumGIS. The result lies at about 15.1E / 37.5N. This is correct.
I submitted this as a support case to our local distributor, ESRI UK. Will post solution.
Hello,
Thank you very much for providing a link to some data. The minute I looked at the .prj file I was able to figure out what was happening. The .prj file is using these projection parameters:
latitude_of_center longitude_of_center
ESRI software expects
latitude_of_origin central_meridian
The "center" parameters aren't recognized as corresponding to latitude of origin and central meridian, so internally these two parameters have values of 0,0. That's why the longitude values are around 4E and the latitude values are around 14S.
I've attached a .prj file (renamed .txt so it can be uploaded) with the ESRI version of ETRS-LAEA. Please redefine the data with that coordinate system, and I think you will find it working much better.
Another issue is that we use different names in the ETRS 1989 definition which triggers "these are not the same".
Hi, I have a similar problem but different orientation... How can I convert WGS 1984 to ETRS 1989? When I'm opening "project" option the only possibility which can be chosen is to convert ETRS to WGS, even when initial projection is WGS. Does anybody know how it can be done? Thank's a lot!
A transformation is always defined in a certain direction. All supported transformation methods (algorithms) are inversible. The software will apply a transformation correctly no matter which direction it should be applied.
In ArcGIS 10.1 there are five different options of going from Irish GRID (IG) to LAEA. The results from the different transformations are not consistent with each other, and furthermore these differences vary across the country (Ireland).
A similar issue occurs with transformation from WGS84 to LAEA (where in 10.1 there are about twenty options). In 10.0, three options are available (unknown/on the fly, TM65_To_ETRS_1989_1 and TM65_To_ETRS_1989_NTv2 , depending on if you have a prj file associated with your source file and if you have the NTv2 installed) again resulting in deviations in outputs of up to 70m.
Naturally, deviations are to be expected from the different transformations, but as we do not have any reference data in LAEA to check this data against, could ESRI Inc advise on which transformation should be used (IG to LAEA, WGS84 to LAEA), in 10.0 and in 10.1 and if available, provide an accuracy statement for the recommended transformations?
I assume the initial part of the step will be to use the NTv2 Ireland transformation which has been created by Esri, which I have attached.
