/*
* Copyright (C) 2011-2012 Dr. John Lindsay <jlindsay@uoguelph.ca>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package plugins;
import java.util.Date;
import whitebox.geospatialfiles.WhiteboxRaster;
import whitebox.interfaces.WhiteboxPlugin;
import whitebox.interfaces.WhiteboxPluginHost;
/**
* Tool can be used to perform a simple landform classification based on measures of slope gradient and curvature derived from a user-specified digital elevation model (DEM).
*
* @author Dr. John Lindsay email: jlindsay@uoguelph.ca
*/
public class Pennocks_Landform_Classification implements WhiteboxPlugin {
private WhiteboxPluginHost myHost = null;
private String[] args;
// Constants
private static final double LnOf2 = 0.693147180559945;
/**
* Used to retrieve the plugin tool's name. This is a short, unique name
* containing no spaces.
*
* @return String containing plugin name.
*/
@Override
public String getName() {
return "Pennocks_Landform_Classification";
}
/**
* Used to retrieve the plugin tool's descriptive name. This can be a longer
* name (containing spaces) and is used in the interface to list the tool.
*
* @return String containing the plugin descriptive name.
*/
@Override
public String getDescriptiveName() {
return "Pennock's Landform Classification";
}
/**
* Used to retrieve a short description of what the plugin tool does.
*
* @return String containing the plugin's description.
*/
@Override
public String getToolDescription() {
return "Classifies hillslope zones based on Slope, Profile Curvature, "
+ "and Plan Curvature. Zones are based upon Pennock`s (1987) "
+ "interpretation of Ruhe`s (1960) landform classes. These "
+ "classes are; Level ground, Divergent and Convergent Backslopes, "
+ "Divergent and Convergent Shoulders, and Divergent and "
+ "Convergent Foreslopes.";
}
/**
* Used to identify which toolboxes this plugin tool should be listed in.
*
* @return Array of Strings.
*/
@Override
public String[] getToolbox() {
String[] ret = {"LandformClass"};
return ret;
}
/**
* Sets the WhiteboxPluginHost to which the plugin tool is tied. This is the
* class that the plugin will send all feedback messages, progress updates,
* and return objects.
*
* @param host The WhiteboxPluginHost that called the plugin tool.
*/
@Override
public void setPluginHost(WhiteboxPluginHost host) {
myHost = host;
}
/**
* Used to communicate feedback pop-up messages between a plugin tool and
* the main Whitebox user-interface.
*
* @param feedback String containing the text to display.
*/
private void showFeedback(String message) {
if (myHost != null) {
myHost.showFeedback(message);
} else {
System.out.println(message);
}
}
/**
* Used to communicate a return object from a plugin tool to the main
* Whitebox user-interface.
*
* @return Object, such as an output WhiteboxRaster.
*/
private void returnData(Object ret) {
if (myHost != null) {
myHost.returnData(ret);
}
}
private int previousProgress = 0;
private String previousProgressLabel = "";
/**
* Used to communicate a progress update between a plugin tool and the main
* Whitebox user interface.
*
* @param progressLabel A String to use for the progress label.
* @param progress Float containing the progress value (between 0 and 100).
*/
private void updateProgress(String progressLabel, int progress) {
if (myHost != null && ((progress != previousProgress)
|| (!progressLabel.equals(previousProgressLabel)))) {
myHost.updateProgress(progressLabel, progress);
}
previousProgress = progress;
previousProgressLabel = progressLabel;
}
/**
* Used to communicate a progress update between a plugin tool and the main
* Whitebox user interface.
*
* @param progress Float containing the progress value (between 0 and 100).
*/
private void updateProgress(int progress) {
if (myHost != null && progress != previousProgress) {
myHost.updateProgress(progress);
}
previousProgress = progress;
}
/**
* Sets the arguments (parameters) used by the plugin.
*
* @param args An array of string arguments.
*/
@Override
public void setArgs(String[] args) {
this.args = args.clone();
}
private boolean cancelOp = false;
/**
* Used to communicate a cancel operation from the Whitebox GUI.
*
* @param cancel Set to true if the plugin should be canceled.
*/
@Override
public void setCancelOp(boolean cancel) {
cancelOp = cancel;
}
private void cancelOperation() {
showFeedback("Operation cancelled.");
updateProgress("Progress: ", 0);
}
private boolean amIActive = false;
/**
* Used by the Whitebox GUI to tell if this plugin is still running.
*
* @return a boolean describing whether or not the plugin is actively being
* used.
*/
@Override
public boolean isActive() {
return amIActive;
}
/**
* Used to execute this plugin tool.
*/
@Override
public void run() {
amIActive = true;
String inputHeader = null;
String outputHeader = null;
int row, col, x, y;
int progress = 0;
double z;
int i, c;
int[] dX = new int[]{1, 1, 1, 0, -1, -1, -1, 0};
int[] dY = new int[]{-1, 0, 1, 1, 1, 0, -1, -1};
double zFactor = 0;
double slopeThreshold = 0;
double profCurvThreshold = 0;
double planCurvThreshold = 0;
double radToDeg = 180 / Math.PI;
if (args.length <= 0) {
showFeedback("Plugin parameters have not been set.");
return;
}
for (i = 0; i < args.length; i++) {
if (i == 0) {
inputHeader = args[i];
} else if (i == 1) {
outputHeader = args[i];
} else if (i == 2) {
zFactor = Double.parseDouble(args[i]);
} else if (i == 3) {
slopeThreshold = Double.parseDouble(args[i]);
} else if (i == 4) {
profCurvThreshold = Double.parseDouble(args[i]);
} else if (i == 5) {
planCurvThreshold = Double.parseDouble(args[i]);
}
}
// check to see that the inputHeader and outputHeader are not null.
if ((inputHeader == null) || (outputHeader == null)) {
showFeedback("One or more of the input parameters have not been set properly.");
return;
}
try {
WhiteboxRaster DEM = new WhiteboxRaster(inputHeader, "r");
int rows = DEM.getNumberRows();
int cols = DEM.getNumberColumns();
double noData = DEM.getNoDataValue();
double gridResX = DEM.getCellSizeX();
double gridResY = DEM.getCellSizeY();
double diagGridRes = Math.sqrt(gridResX * gridResX + gridResY * gridResY);
double[] gridLengths = new double[]{diagGridRes, gridResX, diagGridRes, gridResY, diagGridRes, gridResX, diagGridRes, gridResY};
double Zx, Zy, Zxx, Zyy, Zxy, p, Zx2, q, Zy2;
double fx, fy;
double gridResTimes2 = gridResX * 2;
double gridResSquared = gridResX * gridResX;
double fourTimesGridResSquared = gridResSquared * 4;
double planCurv, profCurv, slope;
double eightGridRes = 8 * gridResX;
double[] N = new double[8];
WhiteboxRaster output = new WhiteboxRaster(outputHeader, "rw",
inputHeader, WhiteboxRaster.DataType.FLOAT, -999);
output.setPreferredPalette("landclass.pal");
output.setDataScale(WhiteboxRaster.DataScale.CONTINUOUS);
for (row = 0; row < rows; row++) {
for (col = 0; col < cols; col++) {
z = DEM.getValue(row, col);
if (z != noData) {
z = z * zFactor;
//get the neighbouring cell Z values
for (c = 0; c < 8; c++) {
N[c] = DEM.getValue(row + dY[c], col + dX[c]);
if (N[c] != noData) {
N[c] = N[c] * zFactor;
} else {
N[c] = z;
}
}
//calculate each of the terms
Zx = (N[1] - N[5]) / gridResTimes2;
Zy = (N[7] - N[3]) / gridResTimes2;
Zxx = (N[1] - 2 * z + N[5]) / gridResSquared;
Zyy = (N[7] - 2 * z + N[3]) / gridResSquared;
Zxy = (-N[6] + N[0] + N[4] - N[2]) / fourTimesGridResSquared;
Zx2 = Zx * Zx;
Zy2 = Zy * Zy;
p = Zx2 + Zy2;
q = p + 1;
if (p > 0) {
//eqn for slope
fy = (N[6] - N[4] + 2 * (N[7] - N[3]) + N[0] - N[2]) / eightGridRes;
fx = (N[2] - N[4] + 2 * (N[1] - N[5]) + N[0] - N[6]) / eightGridRes;
slope = Math.atan(Math.sqrt(fx * fx + fy * fy));
slope = slope * radToDeg;
//Plan curve calc
planCurv = -1 * (Zxx * Zy2 - 2 * Zxy * Zx * Zy + Zyy * Zx2) / Math.pow(p, 1.5);
planCurv = (planCurv * radToDeg);
//Profile curve calc
profCurv = -1 * (Zxx * Zx2 + 2 * Zxy * Zx * Zy + Zyy * Zy2) / Math.pow(p * q, 1.5);
profCurv = (profCurv * radToDeg);
if (profCurv < -profCurvThreshold && planCurv <= -planCurvThreshold & slope > slopeThreshold) {
//Convergent Footslope
output.setValue(row, col, 1);
} else if (profCurv < -profCurvThreshold && planCurv > planCurvThreshold && slope > slopeThreshold) {
//Divergent Footslope
output.setValue(row, col, 2);
} else if (profCurv > profCurvThreshold && planCurv <= planCurvThreshold && slope > slopeThreshold) {
//Convergent Shoulder
output.setValue(row, col, 3);
} else if (profCurv > profCurvThreshold && planCurv > planCurvThreshold && slope > slopeThreshold) {
//Divergent Shoulder
output.setValue(row, col, 4);
} else if (profCurv >= -profCurvThreshold && profCurv < profCurvThreshold && slope > slopeThreshold && planCurv <= -planCurvThreshold) {
//Convergent Backslope
output.setValue(row, col, 5);
} else if (profCurv >= -profCurvThreshold && profCurv < profCurvThreshold && slope > slopeThreshold && planCurv > planCurvThreshold) {
//Divergent Backslope
output.setValue(row, col, 6);
} else if (slope <= slopeThreshold) {
//Level
output.setValue(row, col, 7);
} else {
output.setValue(row, col, noData);
}
} else {
output.setValue(row, col, noData);
}
}
}
if (cancelOp) {
cancelOperation();
return;
}
progress = (int) (100f * row / (rows - 1));
updateProgress(progress);
}
output.addMetadataEntry("Created by the "
+ getDescriptiveName() + " tool.");
output.addMetadataEntry("Created on " + new Date());
DEM.close();
output.close();
// returning a header file string displays the image.
returnData(outputHeader);
String retstr = "LANDFORM CLASSIFICATION KEY\n";
retstr += "\nValue:\tClass";
retstr += "\n1\tConvergent Footslope";
retstr += "\n2\tDivergent Footslope";
retstr += "\n3\tConvergent Shoulder";
retstr += "\n4\tDivergent Shoulder";
retstr += "\n5\tConvergent Backslope";
retstr += "\n6\tDivergent Backslope";
retstr += "\n7\tLevel";
returnData(retstr);
} catch (OutOfMemoryError oe) {
myHost.showFeedback("An out-of-memory error has occurred during operation.");
} catch (Exception e) {
myHost.showFeedback("An error has occurred during operation. See log file for details.");
myHost.logException("Error in " + getDescriptiveName(), e);
} finally {
updateProgress("Progress: ", 0);
// tells the main application that this process is completed.
amIActive = false;
myHost.pluginComplete();
}
}
}