[postgis-users] Getting geometry into ADO

[Val Macduff]

For the benefit of anyone else trying to solve this problem, I had to do two
things to get everything working.

1. Switch to the latest version of the POSTGRESQL35W ODBC driver from
http://www.geocities.jp/inocchichichi/psqlodbc/index.html
2. Add the C7=1 parameter to the ADO connection string.

Many thanks to Hiroshi Inoue for his help.

Val

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net]On Behalf Of Val
Macduff
Sent: Wednesday, 10 May 2006 2:51 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Getting geometry into ADO

I am building a GIS browser interface to PostGIS data using VB6 to read the
PostGIS table. I need to get the complete geometry field into a VB6 Variant
variable to pass to the TatukGIS DK to create a shape.  My select statement
is

    sSelectString = "SELECT SRID(" & msShapeItem & ") as ShapeSRID," & _
                          "AsBINARY(" & msShapeItem & ",'XDR') as SHAPEWKB"
& _
                          " FROM " & msTableName & _
                          " WHERE " & msShapeItem & " IS NOT NULL"

When I use this on a point dataset or a small line dataset everything works
fine but if I try to access polygon data with very large numbers of
coordinates I cannot retrieve a value at all. The statement

vntCoords = rs.Fields("SHAPEWKB").Value

causes an immediate untrappable error.  If I look at the locals before this
happens, the value of SHAPEWKB is given as

<Application-defined or object-defined error>

Trying to fetch the data AsText or raw also results in the same "value"
being shown.

Does anyone know how I can do this?

Thanks, Val



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