[Proj] State Plane Coordinate Zone 6 Conversion Help

[Matt Bartolome]

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.

Thank you,
Matt