How to use

precalculate

method

in

ucar.unidata.geoloc.projection.FlatEarth

/**
 * Set the origin longitude.
 * @param lon   the origin longitude.
 */
public void setOriginLon(double lon) {
  origin.setLongitude(lon);
  lon0 = Math.toRadians(lon);
  precalculate();
}

/**
* Set the origin latitude.
*
* @param lat   the origin latitude.
*/
public void setOriginLat(double lat) {
  origin.setLatitude(lat);
  lat0 = Math.toRadians(lat);
  precalculate();
}

/**
 * Construct a FlatEarth Projection, two standard parellels.
 * For the one standard parellel case, set them both to the same value.
 *
 * @param lat0   lat origin of the coord. system on the projection plane
 * @param lon0   lon origin of the coord. system on the projection plane
 * @param rotAngle   angle of rotation, in degrees
 * @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
 */
public FlatEarth(double lat0, double lon0, double rotAngle) {
  this.lat0     = Math.toRadians(lat0);
  this.lon0     = Math.toRadians(lon0);
  this.rotAngle = Math.toRadians(rotAngle);
  origin        = new LatLonPointImpl(lat0, lon0);
  precalculate();
  addParameter(ATTR_NAME, "flat_earth");
  addParameter("latitude_of_projection_origin", lat0);
  addParameter("longitude_of_projection_origin", lon0);
  addParameter("rotationAngle", rotAngle);
}

/**
 * Construct a FlatEarth Projection, two standard parellels.
 * For the one standard parellel case, set them both to the same value.
 *
 * @param lat0     lat origin of the coord. system on the projection plane
 * @param lon0     lon origin of the coord. system on the projection plane
 * @param rotAngle angle of rotation, in degrees
 * @param radius  earth radius in km
 * @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
 */
public FlatEarth(double lat0, double lon0, double rotAngle, double radius) {
 super("FlatEarth", false);
 this.lat0 = Math.toRadians(lat0);
 this.lon0 = Math.toRadians(lon0);
 this.rotAngle = Math.toRadians(rotAngle);
 this.radius = radius;
 precalculate();
 addParameter(CF.GRID_MAPPING_NAME, "flat_earth");
 addParameter(CF.LATITUDE_OF_PROJECTION_ORIGIN, lat0);
 addParameter(CF.LONGITUDE_OF_PROJECTION_ORIGIN, lon0);
 addParameter(ROTATIONANGLE, rotAngle);
 addParameter(CF.EARTH_RADIUS, radius * 1000);
}

/**
 * Construct a FlatEarth Projection, two standard parellels.
 * For the one standard parellel case, set them both to the same value.
 *
 * @param lat0     lat origin of the coord. system on the projection plane
 * @param lon0     lon origin of the coord. system on the projection plane
 * @param rotAngle angle of rotation, in degrees
 * @param radius  earth radius in km
 * @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
 */
public FlatEarth(double lat0, double lon0, double rotAngle, double radius) {
 super("FlatEarth", false);
 this.lat0 = Math.toRadians(lat0);
 this.lon0 = Math.toRadians(lon0);
 this.rotAngle = Math.toRadians(rotAngle);
 this.radius = radius;
 precalculate();
 addParameter(CF.GRID_MAPPING_NAME, "flat_earth");
 addParameter(CF.LATITUDE_OF_PROJECTION_ORIGIN, lat0);
 addParameter(CF.LONGITUDE_OF_PROJECTION_ORIGIN, lon0);
 addParameter(ROTATIONANGLE, rotAngle);
 addParameter(CF.EARTH_RADIUS, radius * 1000);
}

/**
 * Construct a FlatEarth Projection, two standard parellels.
 * For the one standard parellel case, set them both to the same value.
 *
 * @param lat0     lat origin of the coord. system on the projection plane
 * @param lon0     lon origin of the coord. system on the projection plane
 * @param rotAngle angle of rotation, in degrees
 * @param radius  earth radius in km
 * @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
 */
public FlatEarth(double lat0, double lon0, double rotAngle, double radius) {
 super("FlatEarth", false);
 this.lat0 = Math.toRadians(lat0);
 this.lon0 = Math.toRadians(lon0);
 this.rotAngle = Math.toRadians(rotAngle);
 this.radius = radius;
 precalculate();
 addParameter(CF.GRID_MAPPING_NAME, "flat_earth");
 addParameter(CF.LATITUDE_OF_PROJECTION_ORIGIN, lat0);
 addParameter(CF.LONGITUDE_OF_PROJECTION_ORIGIN, lon0);
 addParameter(ROTATIONANGLE, rotAngle);
 addParameter(CF.EARTH_RADIUS, radius * 1000);
}

/**
 * Construct a FlatEarth Projection, two standard parellels.
 * For the one standard parellel case, set them both to the same value.
 *
 * @param lat0   lat origin of the coord. system on the projection plane
 * @param lon0   lon origin of the coord. system on the projection plane
 *  rotAngle angle of rotation is default to 0.0
 * @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
 */
public FlatEarth(double lat0, double lon0) {
  this.lat0     = Math.toRadians(lat0);
  this.lon0     = Math.toRadians(lon0);
  this.rotAngle = Math.toRadians(0.0);
  origin        = new LatLonPointImpl(lat0, lon0);
  precalculate();
  addParameter(ATTR_NAME, "flat_earth");
  addParameter("latitude_of_projection_origin", lat0);
  addParameter("longitude_of_projection_origin", lon0);
  addParameter("rotationAngle", rotAngle);
  // addParameter("units", "km");
}
// move this to ucar.unit or ucar.unidata.util