[Proj] State Plane Coordinate Zone 6 Conversion Help

[Frank Warmerdam]

Matt Bartolome wrote:
> Hello list,
> 
> I'm trying to convert state plane coordinates from zone 6 (san diego
> county, california)  to latitude longitude and I'm having trouble.
> 
> $ echo "6262009 1854017" | proj -I -f %.4f +proj=utm +zone=6
> +ellps=GRS80 +datum=NAD83 +units=m
> 
> -100.1078       11.6424
> 
> I've also tried plugging in some computed constants I found but I'm
> not sure if they are accurate.
> 
> $ echo "6262009 1854017" | proj -I -f %.4f +proj=utm +ellps=GRS80
> +zone=6 +lat_0=32.166667 +lon_0=-116.25 +datum=NAD83 +k=0.999954142490
> 
> -100.1078       11.6424
> 
> I'm pretty sure the datum NAD83 is correct, as well as the GRS80
> ellipsoid. The values should be close to -116, 32.

Matt,

+proj=utm +zone=6 is not at all the same thing as california state plane
zone 6.

Perhaps you want:

echo "6262009 1854017" | proj -I -f %.4f +init=epsg:2230
-117.2246       32.7499

EPSG 2230 is "NAD83 / California zone 6 (ftUS)"

epsg:2230 looks like:

<2230> +proj=lcc +lat_1=33.88333333333333 +lat_2=32.78333333333333 
+lat_0=32.16666666666666 +lon_0=-116.25 +x_0=2000000.0001016 
+y_0=500000.0001016001 +ellps=GRS80 +datum=NAD83 +to_meter=0.3048006096012192 
+no_defs  <>

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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