org.argeo.app.core/src/org/argeo/app/geo/GeoUtils.java

   1 package org.argeo.app.geo;
   2
   3 import java.io.IOException;
   4 import java.io.Writer;
   5 import java.util.ArrayList;
   6 import java.util.List;
   7
   8 import javax.measure.Quantity;
   9 import javax.measure.quantity.Area;
  10
  11 import org.geotools.data.simple.SimpleFeatureCollection;
  12 import org.geotools.data.simple.SimpleFeatureIterator;
  13 import org.geotools.geometry.jts.JTS;
  14 import org.geotools.referencing.CRS;
  15 import org.geotools.referencing.crs.DefaultGeographicCRS;
  16 import org.locationtech.jts.geom.Coordinate;
  17 import org.locationtech.jts.geom.Point;
  18 import org.locationtech.jts.geom.Polygon;
  19 import org.opengis.feature.simple.SimpleFeature;
  20 import org.opengis.geometry.MismatchedDimensionException;
  21 import org.opengis.referencing.FactoryException;
  22 import org.opengis.referencing.crs.CoordinateReferenceSystem;
  23 import org.opengis.referencing.operation.MathTransform;
  24 import org.opengis.referencing.operation.TransformException;
  25
  26 import si.uom.SI;
  27 import tech.units.indriya.quantity.Quantities;
  28
  29 /** Utilities around geographical format, mostly wrapping GeoTools patterns. */
  30 public class GeoUtils {
  31
  32         /** In square meters. */
  33         public static Quantity<Area> calcArea(SimpleFeature feature) {
  34                 try {
  35                         Polygon p = (Polygon) feature.getDefaultGeometry();
  36                         Point centroid = p.getCentroid();
  37                         String code = "AUTO:42001," + centroid.getX() + "," + centroid.getY();
  38                         CoordinateReferenceSystem auto = CRS.decode(code);
  39
  40                         MathTransform transform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);
  41
  42                         Polygon projed = (Polygon) JTS.transform(p, transform);
  43                         return Quantities.getQuantity(projed.getArea(), SI.SQUARE_METRE);
  44                 } catch (MismatchedDimensionException | FactoryException | TransformException e) {
  45                         throw new IllegalStateException("Cannot claculate area of feature");
  46                 }
  47         }
  48
  49         public static void exportToSvg(SimpleFeatureCollection features, Writer out, int width, int height) {
  50                 try {
  51                         double minY = Double.POSITIVE_INFINITY;
  52                         double maxY = Double.NEGATIVE_INFINITY;
  53                         double minX = Double.POSITIVE_INFINITY;
  54                         double maxX = Double.NEGATIVE_INFINITY;
  55                         List<String> shapes = new ArrayList<>();
  56                         for (SimpleFeatureIterator it = features.features(); it.hasNext();) {
  57                                 SimpleFeature feature = it.next();
  58                                 StringBuffer sb = new StringBuffer();
  59                                 sb.append("<polyline style=\"stroke-width:1;stroke:#000000;fill:none;\" points=\"");
  60
  61                                 Polygon p = (Polygon) feature.getDefaultGeometry();
  62                                 Point centroid = p.getCentroid();
  63                                 String code = "AUTO:42001," + centroid.getX() + "," + centroid.getY();
  64                                 CoordinateReferenceSystem auto = CRS.decode(code);
  65
  66                                 MathTransform transform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);
  67
  68                                 Polygon projed = (Polygon) JTS.transform(p, transform);
  69
  70                                 for (Coordinate coord : projed.getCoordinates()) {
  71                                         double x = coord.x;
  72                                         if (x < minX)
  73                                                 minX = x;
  74                                         if (x > maxX)
  75                                                 maxX = x;
  76                                         double y = -coord.y;
  77                                         if (y < minY)
  78                                                 minY = y;
  79                                         if (y > maxY)
  80                                                 maxY = y;
  81                                         sb.append(x + "," + y + " ");
  82                                 }
  83                                 sb.append("\">");
  84                                 sb.append("</polyline>\n");
  85                                 shapes.add(sb.toString());
  86
  87                         }
  88                         double viewportHeight = maxY - minY;
  89                         double viewportWidth = maxX - minX;
  90                         out.write("<svg xmlns=\"http://www.w3.org/2000/svg\"\n");
  91                         out.write(" width=\"" + width + "\"\n");
  92                         out.write(" height=\"" + height + "\"\n");
  93                         out.write(" viewBox=\"" + minX + " " + minY + " " + viewportWidth + " " + viewportHeight + "\"\n");
  94                         out.write(" preserveAspectRatio=\"xMidYMid meet\"\n");
  95                         out.write(">\n");
  96                         for (String shape : shapes) {
  97                                 out.write(shape);
  98                                 out.write("\n");
  99                         }
 100                         out.write("</svg>");
 101                 } catch (IOException | FactoryException | MismatchedDimensionException | TransformException e) {
 102                         throw new RuntimeException("Cannot export to SVG", e);
 103                 }
 104         }
 105
 106         /** Singleton. */
 107         private GeoUtils() {
 108         }
 109 }