Geotools中实现NC转等值面

概述：
前面的文章有实现IDW插值并生成等值面的，本文在前文基础上实现气象NC数据生成等值面。

效果：


Arcgis预览图


实现后
3、代码
package com.lzugis.netcdf;

import com.lzugis.CommonMethod;
import com.lzugis.geotools.EquiSurface;
import ucar.nc2.NetcdfFile;
import ucar.nc2.Variable;
import ucar.nc2.dataset.NetcdfDataset;
import wContour.Contour;
import wContour.Global.Border;
import wContour.Global.PolyLine;
import wContour.Global.Polygon;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Nc2EquiSurface {
private static String rootPath = System.getProperty("user.dir");
private EquiSurface equ = new EquiSurface();

public Map getNcData(String ncpath) {
Map map = new HashMap();
NetcdfFile ncfile = null;
try {
ncfile = NetcdfDataset.open(ncpath);
Variable varLon = ncfile.findVariable("lon");
Variable varLat = ncfile.findVariable("lat");
Variable varPre = ncfile.findVariable("TEM");
float[] lon = (float[]) varLon.read().copyToNDJavaArray();
float[] lat = (float[]) varLat.read().copyToNDJavaArray();
float[][] pre = (float[][]) varPre.read().copyToNDJavaArray();
double[] dLon = new double[lon.length], dLat = new double[lon.length];
double[][] dPre = new double[pre.length][pre[0].length];
for (int i = 0, len = lon.length; i < len; i++) {
dLon[i] = Double.parseDouble(String.valueOf(lon[i]));
}
for (int i = 0, len = lat.length; i < len; i++) {
dLat[i] = Double.parseDouble(String.valueOf(lat[i]));
}
for (int i = 0, len = pre.length; i < len; i++) {
float[] _pre = pre[i];
for (int j = 0, jlen = _pre.length; j < jlen; j++) {
dPre[i][j] = Double.parseDouble(String.valueOf(_pre[j]));
}
}

map.put("lon", dLon);
map.put("lat", dLat);
map.put("tem", dPre);
} catch (IOException e1) {
e1.printStackTrace();
}
return map;
}

public String nc2EquiSurface(Map ncData, double[] dataInterval) {
String geojsonpogylon = "";

List<PolyLine> cPolylineList = new ArrayList<PolyLine>();
List<Polygon> cPolygonList = new ArrayList<Polygon>();

double[][] _gridData = (double[][]) ncData.get("tem");
int[][] S1 = new int[_gridData.length][_gridData[0].length];
double[] _X = (double[]) ncData.get("lon"), _Y = (double[]) ncData.get("lat");
double _undefData = -9999.0;
List<Border> _borders = Contour.tracingBorders(_gridData, _X, _Y,
S1, _undefData);
int nc = dataInterval.length;
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 = equ.getPolygonGeoJson(cPolygonList);

return geojsonpogylon;
}

public static void main(String[] args) {
Nc2EquiSurface nc2equ = new Nc2EquiSurface();
CommonMethod cm = new CommonMethod();

long start = System.currentTimeMillis();
String ncpath = rootPath + "/data/nc/gdfs1.nc";

//获取NC的数据
Map map = nc2equ.getNcData(ncpath);

//根据NC生成等值面
double[] dataInterval = new double[]{0, 5, 10, 15, 20, 25, 30, 35, 40, 45};
String strGeojson = nc2equ.nc2EquiSurface(map, dataInterval);

String strFile = rootPath + "/out/china_pre.json";
cm.append2File(strFile, strGeojson);

System.out.println("Total cost:" + (System.currentTimeMillis() - start));
}
}----------------------------------------------------------------------------------------------

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