# Conversion of NAM Lambert Conformal coordinate system to NAD 1983 UTM Zone 11N

I am attempting to convert the NAM wind data coordinate system using data from the thredds server:

``````Catalog = TDSCatalog('http://thredds.ucar.edu/thredds/catalog/grib/NCEP/GFS/'
'Global_0p25deg/catalog.xml?dataset=grib/NCEP/GFS/Global_0p25deg/Best')
``````

using Siphon. I have extracted the lat/long values and have the pyproj string:

``````Proj('+proj=lcc +lat_1=12.190, +lon_0 = -133.459 +datum=NAD83 +no_defs')
``````

but I am not sure if this is correct. Using the right string, how might I convert to the NAD 1983 UTM Zone 11N coordinate system and is an intermediate projection conversion needed?

New contributor
Justin Dhooghe is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
• Is the lat/lon data in 1-dimensional arrays or in 2-dimensional arrays? If the lat/lon data is in 2-dimensional arrays, are they equally spaced? – snowman2 Dec 3 at 2:24

I would think that what is needed is a transformation.

From the command:

``````C:\>cs2cs  "+proj=lcc +lat_1=12.190 +lon_0=-133.459 +datum=NAD83 +no_defs"  "+proj=utm +zone=11 +ellps=GRS80 +datum=NAD83 +units=m +no_defs"
0 0
-1357376.19     0.00 0.00
``````

From the console:

``````>>> import pyproj
>>> p1 = pyproj.Proj("+proj=lcc +lat_1=12.190 +lon_0=-133.459 +datum=NAD83 +no_defs")
>>> p2 = pyproj.Proj("+proj=utm +zone=11 +ellps=GRS80 +datum=NAD83 +units=m +no_defs")
>>> x = 0
>>> y = 0
>>> pyproj.transform(p1,p2,x,y)
(-1357376.1901256968, 0.0)
``````
• Thank you, Gabriel. I am wondering why these coordinates are negative when I am used to positive values. Should I take the output and add to it some value to correct for a reference point? – Justin Dhooghe 2 days ago
• You are welcome. Since the `+lon_0` value is `-133.459`, the x = 0 coordinte belongs in that longitude, and return a negative value for UTM 11 (which longitude of origin is `-117`). In fact, the center of that Lambert Comformal Conic projection is out of the scope of the UTM 11 zone. – Gabriel De Luca 2 days ago