[postgis-users] Help wanted creating a custom equal area projection in spatial_ref_sys

Brent Wood pcreso at pcreso.com
Tue Oct 10 15:34:21 PDT 2006


Hi,

I'm trying to create a custom projection around New Zealand for working with
polygon areas. Any comments/advice appreciated.

I figure the following will be as appropriate as anything, please let me know
if I'm wrong!

Albers Conical Equal Area
std parallel            -30
 "      "               -50
lon of central meridian 175
lat of origin           -40
false easting             0
false northing            0
datum                   WGS84
ellipsoid               WGS84

If this is indeed suitable, then if I've got the proj4 command line right, an
SQL to create this in the spatial_ref_sys table would be:

insert into spatial_ref_sys
      (srid,
       auth_name,
       auth_srid,
       proj4text)
values
      (27201,
       'BEN200601',
       27201,
       '+proj=aea +lat_1=-30 +lat_2=-50 +lat=-40 +lon_0=175 +x_0=0 +y_0=0
+ellps=WGS84 +datum=WGS84 +units=m +no_defs'
       );



Thanks,

  Brent Wood




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