com.graphhopper.reader.dem.HeightTile Maven / Gradle / Ivy
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/*
* Licensed to GraphHopper GmbH under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*
* GraphHopper GmbH licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.graphhopper.reader.dem;
import com.graphhopper.storage.DataAccess;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
/**
* One rectangle of height data from Shuttle Radar Topography Mission.
*
*
* @author Peter Karich
*/
public class HeightTile {
private final int minLat;
private final int minLon;
private final int width;
private final int height;
private final int horizontalDegree;
private final int verticalDegree;
private final double lowerBound;
private final double lonHigherBound;
private final double latHigherBound;
private DataAccess heights;
private boolean interpolate;
private final double MIN_ELEVATION_METERS = -12_000;
private final double MAX_ELEVATION_METERS = 9_000;
public HeightTile(int minLat, int minLon, int width, int height, double precision, int horizontalDegree, int verticalDegree) {
this.minLat = minLat;
this.minLon = minLon;
this.width = width;
this.height = height;
this.lowerBound = -1 / precision;
this.lonHigherBound = horizontalDegree + 1 / precision;
this.latHigherBound = verticalDegree + 1 / precision;
this.horizontalDegree = horizontalDegree;
this.verticalDegree = verticalDegree;
}
public HeightTile setInterpolate(boolean interpolate) {
this.interpolate = interpolate;
return this;
}
public boolean isSeaLevel() {
return heights.getHeader(0) == 1;
}
public HeightTile setSeaLevel(boolean b) {
heights.setHeader(0, b ? 1 : 0);
return this;
}
void setHeights(DataAccess da) {
this.heights = da;
}
private short getHeightSample(int x, int y) {
// always keep in mind factor 2 because of short value
return heights.getShort(2L * ((long) y * width + x));
}
private boolean isValidElevation(double elevation) {
return elevation > MIN_ELEVATION_METERS && elevation < MAX_ELEVATION_METERS;
}
private double linearInterpolate(double a, double b, double f) {
// interpolate between a and b but if either are invalid, return the other
return !isValidElevation(a) ? b : !isValidElevation(b) ? a : (a + (b - a) * f);
}
public double getHeight(double lat, double lon) {
double deltaLat = Math.abs(lat - minLat);
double deltaLon = Math.abs(lon - minLon);
if (deltaLat > latHigherBound || deltaLat < lowerBound)
throw new IllegalStateException("latitude not in boundary of this file:" + lat + "," + lon + ", this:" + this.toString());
if (deltaLon > lonHigherBound || deltaLon < lowerBound)
throw new IllegalStateException("longitude not in boundary of this file:" + lat + "," + lon + ", this:" + this.toString());
double elevation;
if (interpolate) {
double x = (width - 1) * deltaLon / horizontalDegree;
double y = (height - 1) * (1 - deltaLat / verticalDegree);
int left = (int) x;
int top = (int) y;
int right = left + 1;
int bottom = top + 1;
double w00 = getHeightSample(left, top);
double w01 = getHeightSample(left, bottom);
double w10 = getHeightSample(right, top);
double w11 = getHeightSample(right, bottom);
double topEle = linearInterpolate(w00, w10, x - left);
double bottomEle = linearInterpolate(w01, w11, x - left);
elevation = linearInterpolate(topEle, bottomEle, y - top);
} else {
// first row in the file is the northernmost one
// http://gis.stackexchange.com/a/43756/9006
int x = (int) (width / horizontalDegree * deltaLon);
// different fallback methods for lat and lon as we have different rounding (lon -> positive, lat -> negative)
if (x >= width)
x = width - 1;
int y = height - 1 - (int) (height / verticalDegree * deltaLat);
if (y < 0)
y = 0;
elevation = getHeightSample(x, y);
}
return isValidElevation(elevation) ? elevation : Double.NaN;
}
public void toImage(String imageFile) throws IOException {
ImageIO.write(makeARGB(), "PNG", new File(imageFile));
}
protected BufferedImage makeARGB() {
BufferedImage argbImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics g = argbImage.getGraphics();
long len = width * height;
for (int i = 0; i < len; i++) {
int lonSimilar = i % width;
// no need for width - y as coordinate system for Graphics is already this way
int latSimilar = i / height;
int green = Math.abs(heights.getShort(i * 2));
if (green == 0) {
g.setColor(new Color(255, 0, 0, 255));
} else {
int red = 0;
while (green > 255) {
green = green / 10;
red += 50;
}
if (red > 255)
red = 255;
g.setColor(new Color(red, green, 122, 255));
}
g.drawLine(lonSimilar, latSimilar, lonSimilar, latSimilar);
}
g.dispose();
return argbImage;
}
public BufferedImage getImageFromArray(int[] pixels, int width, int height) {
BufferedImage tmpImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
tmpImage.setRGB(0, 0, width, height, pixels, 0, width);
return tmpImage;
}
@Override
public String toString() {
return minLat + "," + minLon;
}
}