add the possibility to define a triangulation tolerance for the case …

…of list of linestring

gama.core/src/gama/core/common/geometry/GeometryUtils.java

@@ -704,10 +704,10 @@ public static IList<IShape> voronoi(final IScope scope, final IList<GamaPoint> p
 	 *            the lines
 	 * @return the i list
 	 */
-	public static IList<IShape> triangulation(final IScope scope, final IList<IShape> lines) {
+	public static IList<IShape> triangulation(final IScope scope, final IList<IShape> lines, double tol) {
 		final IList<IShape> geoms = GamaListFactory.create(Types.GEOMETRY);
 		final ConformingDelaunayTriangulationBuilder dtb = new ConformingDelaunayTriangulationBuilder();
-
+		dtb.setTolerance(tol);
 		final Geometry points = GamaGeometryType.geometriesToGeometry(scope, lines).getInnerGeometry();
 		dtb.setSites(points);
 		dtb.setConstraints(points);
@@ -720,6 +720,7 @@ public static IList<IShape> triangulation(final IScope scope, final IList<IShape
 		return geoms;
 	}
 
+
 	/**
 	 * Triangulation.
 	 *

gama.core/src/gama/gaml/operators/Spatial.java

@@ -3682,6 +3682,7 @@ public static IList<IShape> triangulate(final IScope scope, final IShape g) {
 			return GeometryUtils.triangulation(scope, g.getInnerGeometry(), 0.0, 0.0, false);
 		}
 
+
 		/**
 		 * Triangulate.
 		 *
@@ -3735,8 +3736,28 @@ public static IList<IShape> triangulate(final IScope scope, final IShape g, fina
 		@no_test
 		public static IList<IShape> triangulate(final IScope scope, final IList<IShape> gs) {
 			if (gs == null || gs.isEmpty()) return null;
-			return GeometryUtils.triangulation(scope, gs);
+			return GeometryUtils.triangulation(scope, gs, 0.0);
 		}
+
+
+		@operator (
+				value = { "triangulate", "to_triangles" },
+				content_type = IType.GEOMETRY,
+				category = { IOperatorCategory.SPATIAL, IOperatorCategory.SP_TRANSFORMATIONS },
+				concept = { IConcept.GEOMETRY, IConcept.SPATIAL_COMPUTATION, IConcept.SPATIAL_TRANSFORMATION })
+		@doc (
+				value = "A list of geometries (triangles) corresponding to the Delaunay triangulation computed from the list of polylines with the given tolerance for the triangulation",
+				masterDoc = true,
+				examples = { @example (
+						value = "triangulate([line([{0,50},{100,50}]), line([{50,0},{50,100}], 0.01))",
+						equals = "the list of geometries (triangles) corresponding to the Delaunay triangulation of the geometry of the agent applying the operator with the a tolerance of 0.01 for the triangulation.",
+						test = false) })
+		@no_test
+		public static IList<IShape> triangulate(final IScope scope, final IList<IShape> gs, final double tol) {
+			if (gs == null || gs.isEmpty()) return null;
+			return GeometryUtils.triangulation(scope, gs, tol);
+		}
+
 
 		/**
 		 * Triangulate.

gama.library/models/Data/Data Importation/models/Contour Lines.gaml

@@ -15,13 +15,16 @@ global {
 
 	//define the size of the world from the countour line shapefile
 	geometry shape <- envelope(shape_file_cl);
+
+        //tolerance for the triangulation; if an error appears during the triangulation, a workaround consists in increasing this tolerance (0.01 for instance).
+	float tolerance <- 0.0;
 
 	init {
 		//create the contour line agents from the shapefile, and init the elevation for each agent
 		create contour_line from: shape_file_cl with: [elevation:: float(read("ELEVATION"))];
 
 		//triangulate the contour lines
-		list<geometry> triangles  <- triangulate (list(contour_line));
+		list<geometry> triangles  <- triangulate (list(contour_line), tolerance);
 
 		//for each triangle geometry, create a triangle_ag agent and compute the elevation of each of its points (and modified their z value)
 		loop tr over: triangles {