[Mapserver-west] Found the answer

Sun May 8 21:06:08 EDT 2005

Mike,
I'd like to see a listing of your database table.  Do you actually have a 
field called "POINT" in the db?   Can you show us the output from:
> ogrinfo virtual.ovf -al  ?

As an aside, there is also a section on VRT in our guide here: 
http://www.maptools.org/dl/docs/mapserv/MsVectorDataGuide.pdf

I'm not sure if it's any different than what you've seen.  It has a dozen or 
so formats shown in detail.

On May 8, 2005 05:11 pm, you wrote:
> 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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