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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.

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  • 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
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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.

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