I have a shapefile from Mexico´s INEGI site that doesn´t have a .prj file. I am having trouble defining the projection in ArcGIS. INEGI tells me it is projected as Lambert Conformal Conical with a ITRF92 GCS. From what I understand, this GCS should be the same as WGS84 (I have used this with other INEGI files and it matched). This combination of LCC & WGS84 doesn't exist in ESRI´s system, so I tried to create a custom projection coordinate system with the following information given by INEGI:

longitude of origin: -102.0, 
latitude of origin: 12.0, 
standard parallel 1: 17.5,
standard parallel 2: 29.5, 
false easting: 2500000.0 m, 
false northing: 0.0 m

But this doesn´t work - ArcGIS puts the file in Africa, not Mexico (though it seems to be the right scale).

I´m wondering if there is something going wrong with the GCS, for which INEGI gives this information:

Datum: ITRF92
Sphereoid: GRS80
Semimajor axis: 6378206.4  
Inverse Flattening 294.9786982

These numbers are not the same as ESRI´s WGS84 or ITRF92, and I can´t figure out how to change them in the "Define Projection" tool.

This is the link to the site that contains the data: http://www.inegi.org.mx/geo/contenidos/recnat/edafologia/vectorial_serieii.aspx

At the bottom are the links to the date, I downloaded "Perfiles de Suelo".

The extent of the data is:

Top -2347872.613848
Bottom -340538.708859
Left -1075400.666415
Right  - 4073175.438209

The data is supposed to cover the nation of Mexico.

  • The spheroid/ellipsoid parameters are for Clarke 1866 which would have been used for NAD27, not ITRF92/WGS84. Would you please add to your question the extent of the shapefile, plus the area that it represents (if the extent isn't lat/lon)? A link to the data if it's available would be useful too. – mkennedy Dec 2 '15 at 22:46
  • Thanks @mkennedy, and apologies for the delay. I am in an area with spotty internet. I´ve added the information to my question. I am completely confused and don´t understand why it would have the parameters for Clarke 1866! – SaiHai Dec 5 '15 at 18:28

This coordinate system is EPSG:6362 and the coordinate system is found in ArcMap under Projected Coordinate Systems -> National Grids -> North America

Considering the False Easting for this projection is 2.5 million meters, the extent of your data seems incorrect.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.