geotools中等值面的生成与OL3中的展示

概述：

本文讲述如何在geotools中IDW插值生成等值面，并根据给定shp进行裁剪，并生成geojson数据，以及Openlayers3中展示。

效果：

插值数据

裁剪结果

裁剪区域数据

实现代码：

1、geotools

package com.lzugis.geotools;

import com.amazonaws.util.json.JSONObject;
import com.lzugis.CommonMethod;
import com.lzugis.geotools.utils.FeaureUtil;
import com.lzugis.geotools.utils.GeoJSONUtil;
import com.vividsolutions.jts.geom.Geometry;
import org.geotools.data.FeatureSource;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureIterator;
import org.geotools.geojson.feature.FeatureJSON;
import org.opengis.feature.Feature;
import org.opengis.feature.simple.SimpleFeature;
import wContour.Contour;
import wContour.Global.Border;
import wContour.Global.PointD;
import wContour.Global.PolyLine;
import wContour.Global.Polygon;
import wContour.Interpolate;

import java.io.File;
import java.io.StringWriter;
import java.nio.charset.Charset;
import java.util.*;

/**
 * Created by admin on 2017/8/29.
 */
public class EquiSurface {
    /**
     * 生成等值面
     *
     * @param trainData    训练数据
     * @param dataInterval 数据间隔
     * @param size         大小，宽，高
     * @param boundryFile  四至
     * @param isclip       是否裁剪
     * @return
     */
    public String calEquiSurface(double[][] trainData,
                                 double[] dataInterval,
                                 int[] size,
                                 String boundryFile,
                                 boolean isclip) {
        String geojsonpogylon = "";
        try {
            double _undefData = -9999.0;
            SimpleFeatureCollection polygonCollection = null;
            List cPolylineList = new ArrayList();
            List cPolygonList = new ArrayList();

            int width = size[0],
                    height = size[1];
            double[] _X = new double[width];
            double[] _Y = new double[height];

            File file = new File(boundryFile);
            ShapefileDataStore shpDataStore = null;

            shpDataStore = new ShapefileDataStore(file.toURL());
            //设置编码
            Charset charset = Charset.forName("GBK");
            shpDataStore.setCharset(charset);
            String typeName = shpDataStore.getTypeNames()[0];
            SimpleFeatureSource featureSource = null;
            featureSource = shpDataStore.getFeatureSource(typeName);
            SimpleFeatureCollection fc = featureSource.getFeatures();

            double minX = fc.getBounds().getMinX();
            double minY = fc.getBounds().getMinY();
            double maxX = fc.getBounds().getMaxX();
            double maxY = fc.getBounds().getMaxY();

            Interpolate.CreateGridXY_Num(minX, minY, maxX, maxY, _X, _Y);
            double[][] _gridData = new double[width][height];

            int nc = dataInterval.length;

            _gridData = Interpolate.Interpolation_IDW_Neighbor(trainData,
                    _X, _Y, 12, _undefData);// IDW插值

            int[][] S1 = new int[_gridData.length][_gridData[0].length];
            List _borders = Contour.tracingBorders(_gridData, _X, _Y,
                    S1, _undefData);

            cPolylineList = Contour.tracingContourLines(_gridData, _X, _Y, nc,
                    dataInterval, _undefData, _borders, S1);// 生成等值线

            cPolylineList = Contour.smoothLines(cPolylineList);// 平滑

            cPolygonList = Contour.tracingPolygons(_gridData, cPolylineList,
                    _borders, dataInterval);

            geojsonpogylon = getPolygonGeoJson(cPolygonList);

            if (isclip) {
                polygonCollection = GeoJSONUtil.readGeoJsonByString(geojsonpogylon);
                FeatureSource dc = clipFeatureCollection(fc, polygonCollection);
                geojsonpogylon = getPolygonGeoJson(dc.getFeatures());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return geojsonpogylon;
    }

    private FeatureSource clipFeatureCollection(FeatureCollection fc,
                                                SimpleFeatureCollection gs) {
        FeatureSource cs = null;
        try {
            List> values = new ArrayList>();
            FeatureIterator contourFeatureIterator = gs.features();
            FeatureIterator dataFeatureIterator = fc.features();
            while (dataFeatureIterator.hasNext()) {
                Feature dataFeature = dataFeatureIterator.next();
                Geometry dataGeometry = (Geometry) dataFeature.getProperty(
                        "the_geom").getValue();
                while (contourFeatureIterator.hasNext()) {
                    Feature contourFeature = contourFeatureIterator.next();
                    Geometry contourGeometry = (Geometry) contourFeature
                            .getProperty("geometry").getValue();
                    double lv = (Double) contourFeature.getProperty("lvalue")
                            .getValue();
                    double hv = (Double) contourFeature.getProperty("hvalue")
                            .getValue();
                    if (dataGeometry.intersects(contourGeometry)) {
                        Geometry geo = dataGeometry
                                .intersection(contourGeometry);
                        Map map = new HashMap();
                        map.put("the_geom", geo);
                        map.put("lvalue", lv);
                        map.put("hvalue", hv);
                        values.add(map);
                    }

                }

            }

            contourFeatureIterator.close();
            dataFeatureIterator.close();

            SimpleFeatureCollection sc = FeaureUtil
                    .creatSimpleFeatureByFeilds(
                            "polygons",
                            "crs:4326,the_geom:MultiPolygon,lvalue:double,hvalue:double",
                            values);
            cs = FeaureUtil.creatFeatureSourceByCollection(sc);

        } catch (Exception e) {
            e.printStackTrace();
            return cs;
        }

        return cs;
    }

    private String getPolygonGeoJson(FeatureCollection fc) {
        FeatureJSON fjson = new FeatureJSON();
        StringBuffer sb = new StringBuffer();
        try {
            sb.append("{\"type\": \"FeatureCollection\",\"features\": ");
            FeatureIterator itertor = fc.features();
            List list = new ArrayList();
            while (itertor.hasNext()) {
                SimpleFeature feature = (SimpleFeature) itertor.next();
                StringWriter writer = new StringWriter();
                fjson.writeFeature(feature, writer);
                list.add(writer.toString());
            }
            itertor.close();
            sb.append(list.toString());
            sb.append("}");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sb.toString();
    }

    private String getPolygonGeoJson(List cPolygonList) {
        String geo = null;
        String geometry = " { \"type\":\"Feature\",\"geometry\":";
        String properties = ",\"properties\":{ \"hvalue\":";

        String head = "{\"type\": \"FeatureCollection\"," + "\"features\": [";
        String end = "  ] }";
        if (cPolygonList == null || cPolygonList.size() == 0) {
            return null;
        }
        try {
            for (Polygon pPolygon : cPolygonList) {

                List