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<p>Frank, </p>
<p>Thanks for you help. I finally started reading the fine print (NAD27/83, HARN, x_0s and to_meters) and got the system running using 32046 for the vectors and 2924 for the rasters. The system works great. I never new there were so many different coordinate systems for one state.<br/>
<br/>
Paul A. Malabad<br/>
Director of Information Technology<br/>
City of Harrisonburg<br/>
(540) 432-7706<br/>
<br/>
------ Original Message ------<br/>
From: Frank Warmerdam <warmerdam@pobox.com><br/>
Date: Saturday, July 8th, 2006 5:13 PM EDT<br/>
To: Paul A Malabad <malabapa@CI.HARRISONBURG.VA.US><br/>
Subject: Re: [UMN_MAPSERVER-USERS] raster vs shp files extents don't match<br/>
<br/>
Paul A Malabad wrote:<br/>
> I have found out that the DIgital orthos are Virginia State Plane <br/>
> Coordinate system. Through the metadata on the dvd, I found that <br/>
> although the discs read VASPCS North, The metadata actually refers to <br/>
> the VASPCS south. I metadata also refers to the units in US survey <br/>
> foot. whereas the epsg file refers to metre. I have tried using the <br/>
> information from the meta to create a separate projection, but it is not <br/>
> working correctly. Can you see anything wrong in my translation.<br/>
<br/>
> PROJECTION<br/>
> "init=epsg:102746"<br/>
> END<br/>
<br/>
Paul,<br/>
<br/>
The ESRI coordinate system number 102746 is in US feet,<br/>
but I believe that the vector coordinates are in meter<br/>
based on the scale of the values. So I'm not sure that 102746<br/>
is right for the vectors. I think EPSG:32146 (VA SPCS North / meter)<br/>
or EPSG:32147 (VA SPCS South / meter) would be more appropriate.<br/>
<br/>
EPSG 32146 can be described with the following proj.4 string:<br/>
<br/>
+proj=lcc +lat_1=39.2 +lat_2=38.03333333333333 +lat_0=37.66666666666666<br/>
+lon_0=-78.5 +x_0=3500000 +y_0=2000000 +ellps=GRS80 +datum=NAD83<br/>
+units=m +no_defs<br/>
<br/>
> PROJECTION<br/>
> "proj=latlong"<br/>
> "ellps=GRS80"<br/>
> "datum=NAD83"<br/>
> "lat_0=36.333333334"<br/>
> "lat_1=36.766666667"<br/>
> "lat_2=37.966666667"<br/>
> "lon_0=-78.5"<br/>
> "units=ft"<br/>
> END<br/>
<br/>
Note that this definition is ignoring the false easting and northing<br/>
which are very important. In my fairly recent file VA SCPS South (ftUS)<br/>
is EPSG:2284 and maps to the PROJ.4 string:<br/>
<br/>
+proj=lcc +lat_1=37.96666666666667 +lat_2=36.76666666666667<br/>
+lat_0=36.33333333333334 +lon_0=-78.5<br/>
+x_0=3500000 +y_0=1000000.0<br/>
+ellps=GRS80 +datum=NAD83 +to_meter=0.3048006096012192 +no_defs<br/>
<br/>
Note the important +x_0 and +y_0 values.<br/>
<br/>
So I *think* you want to use EPSG:32146 for the vector layer, and<br/>
EPSG:2284 for the raster layer. Then you can set your map level<br/>
projection to whichever you wish.<br/>
<br/>
Best regards,<br/>
-- <br/>
---------------------------------------+--------------------------------------<br/>
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com<br/>
light and sound - activate the windows | http://pobox.com/~warmerdam<br/>
and watch the world go round - Rush | President OSGF, http://osgeo.org<br/>
<br/>
</p>
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