I think this might depend on how you set up your output datastore, or what
sort it is - I've attached my code which I've been using on Shapefiles with
no issues (on master)
Ian
On Tue, 19 Mar 2019 at 13:50, <paul.m...@lfv.se> wrote:
> Hi Ian,
>
> This is how I use the generalizer:
>
> *while* (fit.hasNext()) {
>
> SimpleFeature inFeature = fit.next();
>
> MultiPolygon polygon = (MultiPolygon) inFeature.getDefaultGeometry();
>
> * if* (polygon!= *null* && polygon.isSimple()) {
>
> Coordinate[] coords = polygon.getCoordinates();
>
> System.*out*.println("ant coords before = " + coords.length);
>
> // Genarelize all polygons with more then 5 points
>
> * if* (coords.length > 5) {
>
> DouglasPeuckerSimplifier simplifier = *new*
> DouglasPeuckerSimplifier(polygon);
>
> simplifier.setDistanceTolerance(10);
>
> simplifier.setEnsureValid(*false*);
>
> Geometry out = simplifier.getResultGeometry();
>
> coords = out.getCoordinates();
>
> System.*out*.println("ant coords after = " + coords.length);
>
> }
>
> // make all coordinates (x,y,0)
>
> Coordinate[] coords2 = *new* Coordinate[coords.length];
>
> * for*(*int* i = 0; i < coords.length; i++){
>
> Coordinate c = *new* Coordinate(coords[i].x, coords[i].y, 0);
>
> coords2[i] = c;
>
> }
>
> // Do your thing here with the coordinates, but first make sure that
> you create lines correct.
>
> // Just make the polygon to a line string
>
> // coords2 = CreateCenterLineFromCooordinates(coords2);
>
> LineString line = gFactory.createLineString(coords2);
>
> SimpleFeature feature = writer.next();
>
> List<Object> l = inFeature.getAttributes();
>
> * for* (*int* i = 1; i < l.size(); i++) {
>
> // copy all attributes but the first geometry
>
> feature.setAttribute(i, l.get(i));
>
> }
>
> feature.setDefaultGeometry(line);
>
> writer.write();
>
> }
>
> }
>
> writer.close();
>
> tx.commit();
>
> tx.close();
>
> fit.close();
>
> }
>
>
>
> I can see that the coordinates from the generalizer seems correct
> (x,y,n/a) in the debugger.
>
> I have tried to change the coordinates, so that all has (x,y,0), even
> those polygons who are not generalized.
>
> Then I create a line instead of a polygon.
>
> When I look in PostGis the objects that are generalized has no geometry =
> null, but not the others. It must be something that I’m doing wrong or is
> it something I miss?
>
> I have pointed out GeooTools 20.2 in my pom file.
>
>
>
> Kind regards,
>
> Paul
>
>
>
> *Från:* Ian Turton [mailto:ijtur...@gmail.com]
> *Skickat:* den 15 mars 2019 18:15
> *Till:* Malm, Paul (Operations AIM)
> *Kopia:* geotools-users
> *Ämne:* Re: [Geotools-gt2-users] generailisation
>
>
>
> How are you getting the coordinates out? Most output formats will ignore Z
> if it is not set.
>
>
>
> Ian
>
>
>
> On Fri, 15 Mar 2019 at 15:08, <paul.m...@lfv.se> wrote:
>
> Hi Ian!
>
> Thanks, it worked. But there is one problem.
>
> The unchanged objects has (x,y) coordinates and I’m getting (x,y,n/a)
> coordinates for the changed object.
>
> ArcGis does not seem to be able to have this(x,y,z) coordinates or mixed
> coordinate types. The changed objects
>
> has the correct values of x,y but does not show in ArcGis.
>
> Does anyone have any suggestions?
>
> Kind regards,
>
> Paul
>
>
>
> *Från:* Ian Turton [mailto:ijtur...@gmail.com]
> *Skickat:* den 15 mars 2019 09:49
> *Till:* Malm, Paul (Operations AIM)
> *Kopia:* geotools-users
> *Ämne:* Re: [Geotools-gt2-users] generailisation
>
>
>
> You should be able to use a DouglasPeuckerSimplifier to achieve this.
> Something like:
>
>
>
> DouglasPeuckerSimplifier simplifier = new DouglasPeuckerSimplifier(in);
>
> simplifier.setDistanceTolerance(tolerance);
>
> Geometry out = simplifier.getResultGeometry();
>
>
>
> would do it.
>
>
>
> JTS also provides a TopologyPresersevingSimplifier and a
> LineSegmentSimplifier that would also handle your case.
>
>
>
> Ian
>
>
>
> On Fri, 15 Mar 2019 at 06:32, <paul.m...@lfv.se> wrote:
>
> Hi,
>
> I wonder if there is a generalize function using angles.
>
> I have polygons almost like a rectangle/romb. 90 percent has only five
> vertices, but some have more. The extra vertices is om the sides (the
> straight lines).
>
> I would like to remove those vertices and thought that there perhaps is a
> method using a max angle to find the extra vertices.
>
> Kind regards,
>
> Paul
>
> _______________________________________________
> GeoTools-GT2-Users mailing list
> GeoTools-GT2-Users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
>
>
>
>
> --
>
> Ian Turton
>
>
>
>
> --
>
> Ian Turton
>
--
Ian Turton
package com.ianturton.cookbook.operations;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map.Entry;
import org.geotools.data.DataUtilities;
import org.geotools.data.FileDataStore;
import org.geotools.data.FileDataStoreFinder;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.data.simple.SimpleFeatureStore;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.geometry.jts.JTS;
import org.geotools.referencing.CRS;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.MultiPolygon;
import org.locationtech.jts.geom.Point;
import org.locationtech.jts.geom.Polygon;
import org.locationtech.jts.simplify.DouglasPeuckerSimplifier;
import org.locationtech.jts.simplify.TopologyPreservingSimplifier;
import org.locationtech.jts.simplify.VWSimplifier;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
import org.opengis.feature.type.GeometryDescriptor;
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;
public class Simplification {
interface Generalizer {
Geometry simplify(Geometry g, double tolerance);
}
public HashMap<String, Generalizer> generalizers = new HashMap<>();
public Simplification() {
generalizers.put("DouglasPeuker", (geom, tol) -> DouglasPeuckerSimplifier.simplify(geom, tol));
generalizers.put("Topology Pereserving", (geom, tol) -> TopologyPreservingSimplifier.simplify(geom, tol));
generalizers.put("Visvalingam-Whyatt", (geom, tol) -> VWSimplifier.simplify(geom, tol));
}
public static void main(String[] args) throws IOException {
Simplification sim = new Simplification();
FileDataStore ds;
ds = FileDataStoreFinder.getDataStore(new File(args[0]));
SimpleFeatureTypeBuilder typeBuilder = new SimpleFeatureTypeBuilder();
typeBuilder.setName("simples");
SimpleFeatureType inSchema = ds.getSchema();
CoordinateReferenceSystem crs = ds.getSchema().getCoordinateReferenceSystem();
for (AttributeDescriptor a : inSchema.getAttributeDescriptors()) {
if (a instanceof GeometryDescriptor) {
typeBuilder.add("the_geom", a.getType().getBinding(), crs);
} else {
typeBuilder.add(a);
}
}
typeBuilder.add("method", String.class);
typeBuilder.setDefaultGeometry("the_geom");
SimpleFeatureType schema = typeBuilder.buildFeatureType();
SimpleFeatureBuilder builder = new SimpleFeatureBuilder(schema);
List<SimpleFeature> features = new ArrayList<>();
double d = 50000; // 50km
GeometryFactory gf = new GeometryFactory();
try (SimpleFeatureIterator it = ds.getFeatureSource().getFeatures().features()) {
while (it.hasNext()) {
SimpleFeature feature = it.next();
Geometry p = (Geometry) feature.getDefaultGeometry();
builder.set("method", "base");
builder.addAll(feature.getAttributes());
builder.set("the_geom", p);
SimpleFeature f = builder.buildFeature(null);
features.add(f);
Point c = p.getCentroid();
double x = c.getCoordinate().x;
double y = c.getCoordinate().y;
String code = "";
if (CRS.getAxisOrder(crs) == CRS.AxisOrder.EAST_NORTH) {
code = "AUTO2:42001," + x + "," + y;
} else {
code = "AUTO2:42001," + y + "," + x;
}
CoordinateReferenceSystem auto = null;
MathTransform reverse = null;
Geometry r = null;
try {
auto = CRS.decode(code);
MathTransform transform = CRS.findMathTransform(crs, auto);
r = JTS.transform(p, transform);
reverse = CRS.findMathTransform(auto, crs);
} catch (FactoryException | MismatchedDimensionException | TransformException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for (Entry<String, Generalizer> method : sim.generalizers.entrySet()) {
Geometry g = null;
try {
Geometry simplified = method.getValue().simplify(r, d);
g = JTS.transform(simplified, reverse);
} catch (MismatchedDimensionException | TransformException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
MultiPolygon s;
if (g instanceof Polygon) {
s = gf.createMultiPolygon(new Polygon[] { (Polygon) g });
} else {
s = (MultiPolygon) g;
}
if (!s.isEmpty()) {
builder.addAll(feature.getAttributes());
builder.set("the_geom", s);
builder.set("method", method.getKey());
f = builder.buildFeature(null);
if (f != null) {
features.add(f);
}
}
}
}
}
File out = new File("generalisation.shp");
try {
out.createNewFile();
FileDataStore os = FileDataStoreFinder.getDataStore(out);
os.createSchema(schema);
SimpleFeatureStore store = (SimpleFeatureStore) os.getFeatureSource();
store.addFeatures(DataUtilities.collection(features));
os.dispose();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
_______________________________________________
GeoTools-GT2-Users mailing list
GeoTools-GT2-Users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
