Hi
I am attempting to create a simple filter function that would allow me to
place a graphic, using a PointSymbolizer, at an offset to the point
geometry. The function would expect two parameters, an x-offset and a
y-offset (I know this is very simplistic, I will need to take into account
the current map scale later). I would use the function something like this:
pointSymbolizer.setGeometry(ff.function("GeometryOffset",
ff.literal(0.0001), ff.literal(0.0001)));
I created a function by extending FunctionExpressionImpl and registered it,
the evaluate method is shown below:
@Override
public Object evaluate(Object feature)
{
if (!(feature instanceof SimpleFeature))
{
return null;
}
Expression xOffset = (Expression)getParameters().get(0);
Expression yOffset = (Expression)getParameters().get(1);
double first = ((Number)xOffset.evaluate(feature)).doubleValue();
double second = ((Number)yOffset.evaluate(feature)).doubleValue();
Object originalPoint = ((SimpleFeature)feature).getDefaultGeometry();
if (!(originalPoint instanceof Geometry))
{
return null;
}
Coordinate originalCoordinate =
((Geometry)originalPoint).getCoordinate();
Coordinate newCoordinate = new Coordinate(originalCoordinate.x + first,
originalCoordinate.y + second);
GeometryFactory geometryFactory =
JTSFactoryFinder.getGeometryFactory(null);
Point newPoint = geometryFactory.createPoint(newCoordinate);
return newPoint;
}
This is not working, the graphic is not displayed at all. Any hints would
be very appreciated. I noticed in the javadocs for the
setGeometry/getGeometry methods that 'it is advised that the Expression
implements the SpatialTransformationFunction interface', I have not been
able to locate this interface.
Thanks,
Richard
--
View this message in context:
http://n2.nabble.com/Geometry-offset-function-tp4837712p4837712.html
Sent from the geotools-gt2-users mailing list archive at Nabble.com.
------------------------------------------------------------------------------
Download Intel® Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
_______________________________________________
Geotools-gt2-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
