Introduce GIS utilities.

[gpl/argeo-suite.git] / org.argeo.app.core / src / org / argeo / app / geo / GeoUtils.java

diff --git a/org.argeo.app.core/src/org/argeo/app/geo/GeoUtils.java b/org.argeo.app.core/src/org/argeo/app/geo/GeoUtils.java
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+++ b/org.argeo.app.core/src/org/argeo/app/geo/GeoUtils.java
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+package org.argeo.app.geo;
+
+import javax.measure.Quantity;
+import javax.measure.quantity.Area;
+
+import org.geotools.geometry.jts.JTS;
+import org.geotools.referencing.CRS;
+import org.geotools.referencing.crs.DefaultGeographicCRS;
+import org.locationtech.jts.geom.Point;
+import org.locationtech.jts.geom.Polygon;
+import org.opengis.feature.simple.SimpleFeature;
+import org.opengis.geometry.MismatchedDimensionException;
+import org.opengis.referencing.FactoryException;
+import org.opengis.referencing.crs.CoordinateReferenceSystem;
+import org.opengis.referencing.operation.MathTransform;
+import org.opengis.referencing.operation.TransformException;
+
+import si.uom.SI;
+import tech.units.indriya.quantity.Quantities;
+
+/** Utilities around geographical format, mostly wrapping GeoTools patterns. */
+public class GeoUtils {
+
+       /** In square meters. */
+       public static Quantity<Area> calcArea(SimpleFeature feature) {
+               try {
+                       Polygon p = (Polygon) feature.getDefaultGeometry();
+                       Point centroid = p.getCentroid();
+                       String code = "AUTO:42001," + centroid.getX() + "," + centroid.getY();
+                       CoordinateReferenceSystem auto = CRS.decode(code);
+
+                       MathTransform transform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);
+
+                       Polygon projed = (Polygon) JTS.transform(p, transform);
+                       return Quantities.getQuantity(projed.getArea(), SI.SQUARE_METRE);
+               } catch (MismatchedDimensionException | FactoryException | TransformException e) {
+                       throw new IllegalStateException("Cannot claculate area of feature");
+               }
+       }
+
+       /** Singleton. */
+       private GeoUtils() {
+       }
+}