PopulateModel2D.java

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package gov.sandia.geotess.examples;
 
import gov.sandia.geotess.Data;
import gov.sandia.geotess.GeoTessMetaData;
import gov.sandia.geotess.GeoTessModel;
import gov.sandia.geotess.GeoTessPosition;
import gov.sandia.gmp.util.globals.DataType;
import gov.sandia.gmp.util.globals.InterpolatorType;
import gov.sandia.gmp.util.numerical.vector.VectorGeo;
import gov.sandia.gmp.util.numerical.vector.VectorUnit;
 
import java.io.File;
import java.util.Date;
 
/**
 * An example of how to generate a GeoTessModel and populate it with data.
 * At every node in the 4 degree tessellation:
 * <ul>
 * <li>populate a new model with some simple data. The data consists of the
 * distance in radians from every grid node to the geographic location of
 * seismic station ANMO located at Latitude: 34.9462N Longitude: 106.4567W.
 * <li>modify the data by converting it from radians to degrees.
 * <li>interpolate a value from the grid and print the result to the screen.
 * </ul>
 * <p>
 * 
 * @author sballar
 * 
 */
public class PopulateModel2D
{
 /**
  * An example of how to generate a GeoTessModel and populate it with data.
  * At every node in the 4 degree tessellation:
  * <ul>
  * <li>populate a new model with some simple data. The data consists of the
  * distance in radians from every grid node to the geographic location of
  * seismic station ANMO located at Latitude: 34.9462N Longitude: 106.4567W.
  * <li>modify the data by converting it from radians to degrees.
  * <li>interpolate a value from the grid and print the result to the screen.
  * </ul>
  * <p>
  * 
  * @param args path to file geotess_grid_04000.geotess
  */
 public static void main(String[] args)
 {
  try
  {
   if (args.length == 0)
    throw new Exception(
      "\nMust specify a single command line argument specifying " +
      "the path to the file geotess_grid_04000.geotess\n");
   
   System.out.println("Start simple example");
   System.out.println();
 
   // Create a MetaData object in which we can specify information
   // needed for model contruction.
   GeoTessMetaData metaData = new GeoTessMetaData();
 
   // Specify a description of the model. This information is not
   // processed in any way by GeoTess. It is carried around for
   // information purposes.
   metaData.setDescription(String
     .format("Simple example of a GeoTess model,%n"
       + "storing the distance from station ANMO %n"
       + "near Albuquerque, New Mexico, USA%n"
       + "Lat, lon = 34.9462, -106.4567 degrees.%n"
       + "author: Sandy Ballard%n"
       + "contact: sballar@sandia.gov%n"));
 
   // Specify a list of layer names. A model could have many layers,
   // e.g., ("core", "mantle", "crust"), specified in order of
   // increasing radius. This simple example has only one layer.
   metaData.setLayerNames("surface");
   
   // Set layerID equal to the index of the one-and-only layer 
   // in this model.
   int layerID = 0;
 
   // specify the names of the attributes and the units of the
   // attributes in two String arrays. This model only includes
   // one attribute.
   // If this model had two attributes, they would be specified 
   // like this: setAttributes("Distance; Depth", "degrees; km");
   metaData.setAttributes("Distance", "degrees");
 
   // specify the DataType for the data. All attributes, in all
   // profiles, will have the same data type.
   metaData.setDataType(DataType.FLOAT);
   
   // specify the name of the software that is going to generate
   // the model.  This gets stored in the model for future reference.
   metaData.setModelSoftwareVersion("TestSimpleExample 1.0.0");
   
   // specify the date when the model was generated.  This gets 
   // stored in the model for future reference.
   metaData.setModelGenerationDate(new Date().toString());
 
   // specify the path to the file containing the grid to be used for
   // this test.  This information was passed in as a command line
   // argument.  Grids were included in the software delivery and
   // are available from the GeoTess website.
   String gridFile = new File(args[0]).getCanonicalPath();
 
   // call a GeoTessModel constructor to build the model. This will
   // load the grid, and initialize all the data structures to null.
   // To be useful, we will have to populate the data structures.
   GeoTessModel model = new GeoTessModel(gridFile, metaData);
 
   // Each grid vertex will be assigned a single data value consisting
   // of the epicentral distance in degrees from the location of the 
   // grid vertex to seismic station ANMO near Albuquerque, NM.
   // Get unit vector representation of position of station ANMO.
   double[] anmo = VectorGeo.getVectorDegrees(34.9462, -106.4567);
 
   // generate some data and store it in the model. The data consists
   // of the angular distance in degrees from each vertex of the model
   // grid to station ANMO near Albuquerque, NM, USA.
   for (int vtx = 0; vtx < model.getGrid().getNVertices(); ++vtx)
   {
    // retrieve the unit vector corresponding to the i'th vertex of
    // the grid.
    double[] vertex = model.getGrid().getVertex(vtx);
 
    // compute the distance from the vertex to station ANMO.
    float distance = (float) VectorUnit.angleDegrees(anmo, vertex);
    
    // Construct a new Data object that holds a single value of 
    // type float. Data.getData() can be called with multiple values
    // (all of the same type), or an array of values.  In this 
    // very simple example, there is only one value: distance.
    Data data = Data.getDataFloat(distance);
    
    // associate the Data object with the specified vertex of the model.  
    // This instance of setProfile always creates a ProfileSurface object.
    model.setProfile(vtx, data);
   }
 
   // At this point, we have a fully functional GeoTessModel object
   // that we can work with.
 
   // print a bunch of information about the model to the screen.
   System.out.println(model.toString());
 
   // Obtain a GeoTessPosition object from the model. This object
   // can be used to interpolate data from arbitrary points in the
   // model. Specify which type of interpolation is to be used:
   // linear or natural neighbor.
   GeoTessPosition position = model
     .getGeoTessPosition(InterpolatorType.LINEAR);
 
   // set the latitude and longitude of the GeoTessPosition object.
   // This is the position on the Earth where we want to interpolate
   // some data. This is the epicenter of the Sumatra-Andaman
   // earthquake of 2004.
   double lat = 3.316;
   double lon = 95.854;
   position.setTop(layerID, VectorGeo.getVectorDegrees(lat, lon));
 
   System.out.printf(
     "Interpolation lat, lon = %7.3f deg, %7.3f deg%n%n",
     VectorGeo.getLatDegrees(position.getVector()),
     VectorGeo.getLonDegrees(position.getVector()));
 
   // retrieve the interpolated distance value at the most recent
   // location specified in the GeoTessPostion object.
   double distance = position.getValue(0);
 
   // Output the interpolated distance from the position specified in
   // the GeoTessPosition object to station ANMO, in degrees.
   System.out.printf("Interpolated distance from station ANMO = %1.3f degrees%n%n",
       distance);
 
   // compute actual distance from ANMO to the position of interest.
   double actualDistance = VectorUnit.angle(anmo,
     position.getVector());
 
   System.out.printf("Actual distance from station ANMO       = %1.3f degrees%n",
       Math.toDegrees(actualDistance));
 
   System.out.println();
 
   // print out the index of the triangle in which point resides.
   System.out.printf("Interpolated point resides in triangle index = %d%n%n",
     position.getTriangle());
 
   // print out a table with the node indexes, node lat, node lon and
   // interpolation coefficients for the nodes of the triangle that
   // contains the point.
   System.out.println("  Node        Lat        Lon      Coeff");
 
   // get the indexes of the vertices that contribute to the
   // interpolation.
   int[] x = position.getVertices();
 
   // get the interpolation coefficients used in interpolation.
   double[] coef = position.getHorizontalCoefficients();
 
   for (int j = 0; j < x.length; ++j)
   {
    int vtx = x[j];
    System.out.printf(
      "%6d %10.4f %10.4f %10.6f%n",
      vtx,
      VectorGeo.getLatDegrees(model.getGrid().getVertex(vtx)),
      VectorGeo.getLonDegrees(model.getGrid().getVertex(vtx)), 
      coef[j]);
   }
   System.out.printf("%nSimple example completed successfully%n%n");
 
  }
  catch (Exception ex)
  {
   ex.printStackTrace();
  }
 
 }
 
}