[Mapserver-west] Found the answer

[Mike]

Hi all,

I've been trying to connect a table(GPS) that contains X,Y coordinates on my
MSDE database to Mapserver. I've followed the instructions on
http://mapserver.gis.umn.edu/cgi-bin/wiki.pl?VirtualSpatialData
Everything is going great so far but when I try to display the layer I get
this error msg:
===========
msDrawMap(): Image handling error. Failed to draw layer named
'MyVirtualLayer'. 
msOGRLayerInitItemInfo(): OGR error. Invalid Field name: POINT 
===========

Here is my VRT file:
===========
<OGRVRTDataSource>
    <OGRVRTLayer name="GPS">
        <SrcDataSource>ODBC:HOPE,GPS</SrcDataSource> 
 	<SrcLayer>GPS</SrcLayer> 
	<GeometryType>wkbPoint</GeometryType> 
        <LayerSRS>WGS84</LayerSRS>
	<GeometryField encoding="PointFromColumns" x="x" y="y"/> 
    </OGRVRTLayer>
</OGRVRTDataSource>
===========

When I test it using OGR this is what I get:
===========
C:\Inetpub\wwwroot\mhlwang>ogrinfo virtual.ovf
ERROR 4: Update access not supported for VRT datasources.
Had to open data source read-only.
INFO: Open of `virtual.ovf'
using driver `VRT' successful.
1: GPS (Point)
===========

Here is my map file:
===========
MAP
  #IMAGETYPE PNG
   EXTENT 250565.140625 1309136.875000 434428.468750 1438412.625000
   UNITS METERS
   SIZE 800 600
   SHAPEPATH "data"
   IMAGECOLOR 255 255 255
   PROJECTION
    "proj=utm"
    "ellps=evrst30"
    "zone=48"
    "north"
    "no_defs"
  #  "lat_0=45"
  #  "lon_0=100"

  # Alternatively, you can specify an EPSG code.
  #"init=epsg:9808"
  #
  END

#
# Start of web interface definition (including WMS enabling metadata)
#
WEB
  HEADER demo_header.html
  TEMPLATE demo.html
  FOOTER demo_footer.html
#  MINSCALE 1000
#  MAXSCALE 1550000
  IMAGEPATH "C:\Inetpub\wwwroot\tmp\"
  IMAGEURL "/tmp/"
  #METADATA
  #END
END

  # Start of LAYER DEFINITIONS ---------------------------------------------
  LAYER # pursat polygon layer begins here
    NAME pursat
    DATA pursat_srok_bnd
    STATUS DEFAULT
    TYPE POLYGON

    PROJECTION
     # "init=epsg:3148"
     "proj=utm"
     "ellps=evrst30"
     "zone=48"
     "north"
     "no_defs"
    END

    CLASS
      COLOR 255 228 196
      OUTLINECOLOR 32 32 32
    END
  END # States polygon layer ends here

LAYER #begin virtual layer
    NAME "MyVirtualLayer"
    TYPE POINT
    CONNECTIONTYPE OGR
    CONNECTION "C:\Inetpub\wwwroot\mhlwang\virtual.ovf" 
    DATA "GPS" #the name of the OGRVrtLayer
    STATUS DEFAULT
    LABELITEM 'POINT' #use table.name or just name depending on your OVF
file.
    PROJECTION
      #"init=epsg:4326"
     "proj=utm"
     "ellps=evrst30"
     "zone=48"
     "north"
     "no_defs"
    END
    CLASS
      SYMBOL 1
      SIZE 6
      COLOR 255 0 0
      LABEL
	SIZE MEDIUM
	TYPE BITMAP
	COLOR 0 0 0
      END
    END
END
  # End of LAYER DEFINITIONS -------------------------------
END # end of map file/object
===========
 

I've tried changing the LABELITEM 'POINT' to LABELITEM 'GPS.POINT' but that
doesn't seem to work either. 

Any suggestions are welcome! Thanks!

Mike


-----Original Message-----
From: mapserver-west-bounces at lists.maptools.org
[mailto:mapserver-west-bounces at lists.maptools.org] On Behalf Of Tyler
Mitchell
Sent: Thursday, April 21, 2005 6:49 AM
To: mapserver-west at lists.maptools.org
Subject: Re: [Mapserver-west] Found the answer

Good sleuthing Dean.
For those who aren't familiar with the VRT format, it can be used to grab 
non-spatial (tabular) lists of coordinates and create point features.
Dean's 
example is a good one, using an (any!) ODBC data source that has an x and y 
column.  I've used this with a CSV data source before and found it worked 
great.  I think that it can be used with any OGR support data format as
well.

Tyler

On April 20, 2005 10:56 pm, Dean C. Mikkelsen wrote:
> Hi all!
>
> I think I solved my question. I am working possibly with a non-spatial
> database - originally Oracle 8. The hope is to migrate to PostGIS or
> MySQL. I have experience with MySQL.
>
> It appears as though I have to use the Virtual File Format found with
> the OGR. The link is here:
>
> http://www.remotesensing.org/gdal/ogr/drv_vrt.html
>
> In my case, I would have code such as:
> <OGRVRTDataSource>
>
>     <OGRVRTLayer name="lease_polygons">
>
> <SrcDataSource>ODBC:gulf_of_mexico,lease_polygons</SrcDataSource>
>  	<SrcLayer>lease_polygons</SrcLayer>
> 	<GeometryType> wkbPolygon</GeometryType>
>         <LayerSRS>WGS84</LayerSRS>
> 	<GeometryField encoding="PointFromColumns" x="x" y="y"/>
>     </OGRVRTLayer>
>
> </OGRVRTDataSource>
>
> The answer was right in front of me, just a little digging, eh?
>
> Cheers,
> Dean
>
>
>
>
> _______________________________________________
> Mapserver-west mailing list
> Mapserver-west at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/mapserver-west
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