Hi,
As member of the SLD/SE standard working I'm working on a POC to test
the next Feature2DStyle model.
Here you have a first implementation : https://github.com/orbisgis/orbismap
I'm looking for testing Feature2DStyle model with Geotools.
Feature2DStyle supports expression (ParameterValue) for each symbol
elements.
Example to manage the width of a line with a SQL CASE WHEN.
Feature2DStyle style = new Feature2DStyle();
LineSymbolizer lineSymbolizer = new LineSymbolizer();
lineSymbolizer.setGeometryParameter("the_geom");
PenStroke ps = new PenStroke();
ps.setWidth(new Expression("CASE WHEN ST_AREA(THE_GEOM)>10000 then 5
else 1 END"));
SolidFill solidFill = new SolidFill();
ps.setFill(solidFill);
lineSymbolizer.setStroke(ps);
Feature2DRule rule = new Feature2DRule();
rule.addSymbolizer(lineSymbolizer);
style.addRule(rule);
Geotools has an abstract query language and mechanism to run expression
or filter that are translated in the language supported by the datastore
(very useful for POSTGIS and H2GIS).
I have successfully used it on an H2GIS table.
List<Definition> definitions = new ArrayList<Definition>();
definitions.add(new Definition("THE_GEOM",
ECQL.toExpression("centroid(buffer(THE_GEOM, 1))")));
definitions.add(new Definition("AREA",
ECQL.toExpression("AREA(THE_GEOM)/1000")));
SimpleFeatureSource transformed =
TransformFactory.transform((SimpleFeatureSource) fs,
"OUTPUT_TABLE_TEST_F", definitions);
I'd like to apply more complex expressions as the Case When above. It
seems there is a function closed to the SQL Case When called if_then_else.
So I try :
Expression expression =
ECQL.toExpression("if_then_else(area(THE_GEOM)>10,5, 1)");
definitions.add(new Definition("EXP", expression));
SimpleFeatureSource transformed =
TransformFactory.transform((SimpleFeatureSource) fs,
"OUTPUT_TABLE_TEST_F", definitions);
Unfortunately, it returns the following exception
Exception in thread "main" org.geotools.filter.text.cql2.CQLException:
Encountered ">" at line 1, column 28.
Is there a way to execute nested expression with Geotools ECQL parser ?
e.g.
if_then_else(area(THE_GEOM)>10,5, 1)
if_then_else(area(buffer(THE_GEOM))>10,5, 1)
Or a way to implement it ?
Best regards
Erwan Bocher
--
Ingénieur de Recherche CNRS - HDR,
Laboratoire Lab-STICC – UMR 6285
Equipe DECIDE
https://github.com/orbisgis
https://noise-planet.org/
Institut Universitaire de Technologie de Vannes
8, Rue Montaigne - BP 561 56017 Vannes Cedex
T: +33 2 97 62 64 92
W:https://cv.archives-ouvertes.fr/erwan-bocher
W:http://www.labsticc.fr
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