[postgis-users] couldn't get the correct projected values

Don harterc1 at comcast.net
Tue May 20 04:10:07 PDT 2008


OK.  State Plane Coordinates are not the same as latitude and 
longitude.  They are a separate coordinate system like UTM.   I thought 
that it was just a different earth model optimized for the local area.
It is in this definition for srid 2204:
"+proj=lcc +lat_1=35.25 +lat_2=36.41666666666666 
+lat_0=34.66666666666666 +lon_0=-86 +x_0=609601.2192024384 
+y_0=30480.06096012192 +ellps=clrk66 +datum=NAD27 
+to_meter=0.3048006096012192 +no_defs
So Transform probably gives correct values.  I had the wrong srid for my 
data.

Paragon Corporation wrote:
> I think UTMs are offset to be postive, but transforming is not going to
> verify that it will stay positive.
>
>
> On another note you have a typo - I think you meant to say 2204 is ... But
> that is neither here nor there.  2204 is obviously not the right SRID for
> that point.
>
> I think your first guess 4267 is probably right.
>
> Hope that helps,
> Regina
>
>
>
>
>   




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