[postgis-users] Re: SRID for USA_Lambert_Conformal_Conic

[P Kishor]

On 8/20/06, Dylan Lorimer <edylan at google.com> wrote:
> http://lists.maptools.org/pipermail/proj/2002-July/000438.html
> Is listed here..

Amazing! So very many thanks. But, how was I supposed to find this?
How did _you_ find this? This seems to be exactly what I wanted (I
think so), but it is from 4 years ago. Yet, I can't see it referenced
anywhere in current PostGIS docs. Harrrrrumph. Anyway, so I have

# USA_Contiguous_Equidistant_Conic
<102005> +proj=eqdc +lat_0=0.000000000 +lon_0=0.000000000
+lat_1=33.000000000 +lat_2=45.000000000 +x_0=0.000 +y_0=0.000
+ellps=GRS80 +datum=NAD83 +units=m

Am I to assume the following for the above --

srid: 102005 (is that what is inside the angle brackets)?

auth_name: ??

auth_srid: 102005 (in the spatial_ref_sys table, srid seems to be the
same as auth_srid.

proj4text: +proj=eqdc +lat_0=0.000000000 +lon_0=0.000000000
+lat_1=33.000000000 +lat_2=45.000000000 +x_0=0.000 +y_0=0.000
+ellps=GRS80 +datum=NAD83 +units=m

srtext: all the "PROJCS[..." nonsense I already have.
>
>
> On 8/19/06, P Kishor <punkish at eidesis.org> wrote:
> >
>  Well, after a few hours of bouncing around on websites, and scanning
> through rows after rows of similar looking srtext, I give up. I can't
> figure out the srid, auth_name, auth_srid, and proj4text for the
> following srtext --
>
> PROJCS[
>   'USA_Contiguous_Lambert_Conformal_Conic',
>   GEOGCS[
>     'GCS_North_American_1983',
>     DATUM[
>       'D_North_American_1983',
>       SPHEROID['GRS_1980',6378137.0,298.257222101]
>     ],
>     PRIMEM['Greenwich',0.0],
>     UNIT['Degree',0.0174532925199433]
>   ],
>   PROJECTION['Lambert_Conformal_Conic'],
>   PARAMETER['False_Easting',0.0],
>   PARAMETER['False_Northing',0.0],
>   PARAMETER['Central_Meridian',- 96.0],
>   PARAMETER['Standard_Parallel_1',33.0],
>   PARAMETER['Standard_Parallel_2',45.0],
>   PARAMETER['Latitude_Of_Origin',39.0],
>   UNIT['Meter',1.0]
> ];
> -19071146.8131673 -17820932.1267064 61.0351561931566 ;0 100000;0 100000
>
> Any help would be much appreciated as it would stop me for committing
> harm to my dell.
>
>
> On 8/19/06, P Kishor <punkish at eidesis.org> wrote:
> > Right then. So, I have to insert an entry for my SRS in the
> > spatial_ref_sys table. Actually, I am surprised something like
> > "USA_Contiguous_Lambert_Conformal_Conic" is not already
> there... I was
> > assuming this was one of the common USA projections.
> >
> > In any case, I have the srtext nonsense. How do I "discover" the srid,
> > auth_name, auth_srid, and proj4text for it? I am assuming I can't just
> > make stuff up here.
> >
> > Follow-up question -- when I am able to add a row to the
> > spatial_ref_sys table, then what? Do I have to actually transform
> > (project) my datasets into this projection, and store them like that,
> > or do I apply this projection on the fly whenever I do any SQL
> > operation on them?
> >
> > On 8/19/06, Dylan Beaudette <dylan.beaudette at gmail.com> wrote:
> > > ja.
> > >
> > > On 8/19/06, P Kishor <punkish at eidesis.org> wrote:
> > > > On 8/19/06, Dylan Beaudette < dylan.beaudette at gmail.com> wrote:
> > > > > Do you have any of the parameters associated with the Lambert
> > > > > conformal conic projection? You will need these in order to add an
> > > > > entry to the spatial_ref_sys table, with a custom SRID.
> > > >
> > > > Well, I do have the entire SRTEXT. Is that what you meant?
> > > >
> > > >
> > > > >
> > > > > you can get more information on your original file with a tool like
> ogrinfo .
> > > > >
> > > > > Cheers,
> > > > >
> > > > > On 8/19/06, P Kishor <punkish at eidesis.org> wrote:
> > > > > > Actually, I should explain this a bit further --
> > > > > >
> > > > > > (a) I had a Shapefile in USA_Lambert_Conformal_Conic that I
> imported
> > > > > > into PostGIS using the shp2pgsql, psql dance. Whatever I did, its
> SRID
> > > > > > is set to -1.
> > > > > >
> > > > > > (b) I created another dataset from lon/lat explicitly setting its
> SRID to 4326.
> > > > > >
> > > > > > Of course, now I can't do any geometrical analysis on these two
> > > > > > because they are in different spatial references. Ideally, I want
> to
> > > > > > convert my (b) dataset, the points that are in 4326, to the same
> srs
> > > > > > as (a) dataset, namely USA_Lambert_Conformal_Conic.
> > > > > >
> > > > > > Hence my question.
> > > > > >
> > > > > > Many thanks in advance.
> > > > > >
> > > > > > On 8/19/06, P Kishor < punkish at eidesis.org> wrote:
> > > > > > > This is a topic I know very little about. Where do I learn more
> about
> > > > > > > SRIDs, and more specifically,
> > > > > > >
> > > > > > > 1. how do I find SRID for USA_Lambert_Conformal_Conic; and
> > > > > > > 2. use that to change a dataset (project? is that the word wrt
> SRIDs?)
> > > > > > >
> >
> >



-- 
Puneet Kishor http://punkish.eidesis.org/
Nelson Inst. for Env. Studies, UW-Madison http://www.ies.wisc.edu/
Open Source Geospatial Foundation https://edu.osgeo.org/