# pyproj gives inf instead of values

I want to convert the coordinates (639117.49, 6865775.92) from EPSG:4326 to EPSG: 3949, by using the following code:

``````from pyproj import Proj, transform

P4326 = Proj(init='epsg:4326')
P3949 = Proj(init='epsg:3949')

x,y = transform(P4326,P3949,  639117.49, 6865775.92)
``````

The values should be: 1639190.94757331, 8187869.9312972 but I get inf, inf.
What is the mistake?
Otherwise, can I do it directly via PostGIS without using Python?

• 639117.49, 6865775.92 are not in EPSG:4326 which is in degrees between -90/90 and -180/180 so inf is the correct answer. May 18, 2020 at 15:58
• You have at least a problem with logic: your input are using thousand or millions and you expect millions. `epsg:4326` min and max x are -180, +180 and min and max y are -90, +90. Before using pyproj or PostGIS to reproject, you should know what are the real input and output projections before at least one of them is 100% wrong from my 1st sentence. Your input can't be the `639117.49, 6865775.92` for `epsg:4326`: it's simply not possible although you try to. May 18, 2020 at 16:04
• Ah sorry!! Horrible mistake ... Thanks a lot May 18, 2020 at 16:24

Your input values look like they are in EPSG:2154 (RGF93 / Lambert-93), according to projfinder. Using this coordinate system and the point `639117.49, 6865775.92`, I get a point on Rue Jacques Daguerre in Rueil-Malmaison, France. If this is the correct place then I would try the following:

``````from pyproj import Proj, transform

P2154 = Proj(init='epsg:2154')
P3949 = Proj(init='epsg:3949')

x,y = transform(P2154,P3949,  639117.49, 6865775.92)
``````

With this transformation, I get values close to your desired result: `1639117.57, 8188002.59`

• Yes it is. Thanks a lot!! May 18, 2020 at 16:25
• Would be nice to add how you inferred that projection from the data. Did you use projfinder? projfinder.com - my usual go-to for unknown projections... May 18, 2020 at 17:07
• @Spacedman Indeed, I used projfinder after converting his EPSG:3949 expected value to lat/lon, and the match with EPSG:2154 was within about 100m. May 18, 2020 at 19:53