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I am attempting to transform data from Lambert Conformal Conic lat/long and I am having some issues with the results.

The shapefile I am attemtping to transform can be found here: http://tfr.faa.gov/save_pages/0_8326.shp.zip

Since I am using proj.4 I used GDAL/srs to convert the WKT to a proj.4 init string. In order to do that I had to change the WKT projection from "Lambert_Conformal_Conic" to "Lambert_Conformal_Conic_SP2".

The WKT I used:


The resulting proj.4 string from the WKT:

"+proj=lcc +lat_1=38.69259533705237 +lat_2=39.02625053604863 +lat_0=40 +lon_0=-77.03638889 +x_0=0 +y_0=0 +ellps=GRS80 +units=m +no_defs"

The proj.4 string I use for WGS84 lat/long:

"+proj=longlat +ellps=WGS84 +no_defs"

When I get a Lambert Conformal Conic point from the shapefile, I transform it to Lat/Long using this line of code:

pj_transform(pj_lcc, pj_latlong, 1, 1, &fX, &fY, NULL );

Where pj_lcc is my Lambert Conformal Conic projection info, pj_latlong is my WGS84 lat/long projection info and fX, fY are the Lambert Conformal Conic point.

An example result from the above transform is:

lcc point: {4842.47, -71287.5} --- long, lat: {-1.34356, 0.686926}

The lat, long should be around 38º51'34"N, 77º02'11"W (center of the shape according to http://tfr.faa.gov/save_pages/detail_0_8326.html )

Any clues as to what I am doing wrong?

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1 Answer 1

up vote 2 down vote accepted


ogr2ogr -t_srs EPSG:4326 out.shp in.shp

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That worked great! Thank you for the quick reply. –  afarnham Feb 21 '11 at 20:55

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