2

I have some vector files that come without projection. So I have to define my own projection in QGIS. The information that comes with the data reads as following:

Projection: Lambert Azimuthal
Units: Meters
Datum: None
Parameters:
6370997.24063 (radius of the sphere of reference)
100 0 0.000 (longitude of center of projection)
45 0 0.000 (latitude of center of projection)
0.00000 (false easting (meters))
0.00000 (false northing (meters))

The Lambert Azimuthal is an equal area projection. I tried to translate this into a projection definition as:

+proj=laea +lat_0=45. +lon_0=100. +x_0=0 +y_0=0 +datum=none +units=m +a=6370997.24063 +b=6370997.24063

But my data is still wrongly projected.

Improve this question
2
  • Eh? The op says "vector"
    – mdsumner
    Commented Sep 16, 2014 at 11:21
  • You'll need to give more information. What steps do you take, what do you get, and how do you determine wrongness?
    – mdsumner
    Commented Sep 16, 2014 at 11:23

2 Answers 2

Reset to default
3

I guess your data uses US National Atlas Equal Area, EPSG:2163:

+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +a=6370997 +b=6370997 +units=m +no_defs

Note that lon_0 is negative for western longitudes. and datum=none is no official definition.

Improve this answer
1
  • No it is not. It is (+)100 for the longitud.
    – mace
    Commented Sep 16, 2014 at 12:30
1

Ok, in the end I was able to assign a new projection in ArcGIS. Using the data as specified above. I still dont understand what the problem was in QGIS. Possibly the libproj library was broken.

Improve this answer
1
  • I don't think the library is broken. You do need to define a datum, I think, as it's impossible to have a projection without a datum. You could just drop in WGS84.
    – Alex Leith
    Commented Sep 24, 2016 at 22:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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