[mapguide-users] Create feature source from FeatureReader
Kenneth, GEOGRAF A/S
ks at geograf.dk
Sun Jan 6 12:44:08 EST 2008
That is exactly what a layer filter does.
You have to construct it as an FDO filter.
First thing you need is an WKT representation of your filter object.
A polygon looks like this in WKT: "POLYGON((x1 y1, x2 y2, x3 y3, x1 y1))"
If the object you are using as a spatial filter is retrieved from an FDO
datasource, you can retrive the WKT directly by calling a method on the
Next step is to create a copy of a layer, modify the filter and save it
in the session repo.
Then you insert your newly created layer into the runtime map.
Finally, refresh the client map.
The filter string should look like this:
"...geom_column... intersects GEOMFROMTEXT('...wkt...')"
replace ..geom_column... with the name of the column that contains
geometry, and ...wkt... with the WKT of the item you are filtering with.
There are other spatial operators avalible, like "inside".
It is a lot of work to acomplish something that is basically simple.
The end result should be pretty generic.
There is an explanation of all the steps in the Dev guide (PDF), and
sample code in the "buffer" sample code installed with MapGuide.
If you pull it off, and have the legal authority to share the code, you
can add it here:
Regards, Kenneth, GEOGRAF A/S
> OK, i tell you what i need to do.
> I retrieve features from a spatial filter and then i need to show only
> these features.The others can be deleted or hidden.
> I think that in this case the LayerDefinition filter can't help me.
> Thanky for your patience with me :-)
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