[postgis-users] About ESRI Shapefile ...
tc at geosys.com
Wed Apr 19 08:16:02 PDT 2006
Stephen Woodbridge a écrit :
> Thomas Chabaud wrote:
>> Sorry if it's a dumb question, but I wonder why there is no
>> "AsESRIShapefileGeometry(geometry_column)" and
>> "WKTFromESRIShapefile(esri_shapefile_geometry)" that could work like
>> AsText() or GeometryFromText() functions.
>> Is it difficult to do ?
>> I think it could be very useful.
> Hi Thomas,
> 1) A shapefile is not a file it is a set of files so what would you
> expect to get from "AsESRIShapefileGeometry(geometry_column)"
> 2) A geometry_column can contain multiple geometry type, and collection
> which are not compatible with the ESRI Shapefile spec. What would you
> want to happen in this case?
> 3) Lets assume we had the function as you requested it. What would you
> do with it? How would you use the result?
> In general, I think that it is highly unlikely that there is any
> interest in add this function because of the compatibility, and
> restrictions, and the fact that I think you find that most people don't
> think it would be all that useful given that alternatives exist and work
> fine. But you may see a need that I don't see, and I am open to your
> ideas on how you would use such a feature.
> Regarding difficulty, you might look at the source of pqsql2shp, and
> look at what it would take to wrap that in a stored procedure.
> -Steve W.
Sorry, I think I have not been very explicit.
The problem is I have an application using MapObject recordsets, to access
That I would be able to do is for example call a Postgis function that could
take a MapObject geometry in argument, in order to execute sql request like
SELECT AsESRIShapeFileGeometry(geometry_column) AS geom,myid,myotherfield
And then in my application I can directly pass the geometry to a MapObject
recordset, without needing conversion
myMOrecordset.Fields("SHAPE").Value = mysqlrecordset.Fields("geom").value
SQL_Execute("INSERT INTO mytable (id,geometry_column,myfield) values
(myid,WKTFromESRIShapefile(" & myMOrecordset.Fields("SHAPE").Value &
Is there compatibilities problems to add such feature ?
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