Simon Greener wrote:
I know this is a bit after the discussion has completed but I was "listening"
in to the conversation: just had work to do for some customers.
Of course, if you have Oracle Spatial you can use sdo_geom.sdo_arc_densify() to
densify result sets from SELECT statements on the fly. I do this with some
JTS/GeoTools code I use to write shapefiles. However, the issue is that not
everybody has Spatial: most have Locator.
Now I have written converters for complex linestrings and polygons that use three point
arcs in by VB6 and PL/SQL and happily offer to help write anything that the JTS
"keepers of the keys" design.
I note that Deegree is in incubation with OsGeo, but in case you didn't know
Deegree appears to already have the ability to work with Curves in Oracle. I
don't have a copy of the Deegree source code but here is a URL which shows the
relevant Java class:
http://www.java2s.com/Open-Source/Java-Document/GIS/deegree/org/deegree/io/datastore/sql/oracle/JGeometryAdapter.java.htm.
Can this code be folded into JTS/GeoTools? I can code in Java but do not
pretend to be a Java programmer (if you understand my meaning) so it is not
immediately obvious to me why it is not possible to use some of the DeeGree
code.
It could certainly be used in GeoTools (license is LGPL on both sides
etc...), actually when I look at their JGeometry class here it looks to
be based on the same ISO 19107 Geometry ideas as GeoAPI.
Compare:
-
http://geoapi.sourceforge.net/snapshot/javadoc/org/opengis/geometry/Geometry.html
-
http://hillary.lat-lon.de/deegree2_buildresults/api/org/deegree/model/spatialschema/Geometry.html
When you actually look at "Curve" in this model you will find it is a
list of CurveSegment; which is often lines or arcs ... when you look at
where deegree gets down to the metal they appear to just have "straight"
curve segments represented...
-
http://hillary.lat-lon.de/deegree2_buildresults/api/org/deegree/model/spatialschema/CurveSegment.html
-
http://geoapi.sourceforge.net/snapshot/javadoc/org/opengis/geometry/primitive/CurveSegment.html
So there is no free lunch; if someone wants to do curves for real they
need to pay Martin about a half million and lock him away in a closet
for a couple of years. If they want to do full curves and
CoordinateReferneceSystems I am not sure they can pay anyone to do the
work; but I can introduce you to some researchers who are working on it.
Jody
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