Index: trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/CustomProjection.java (revision 9565) @@ -27,4 +27,5 @@ import org.openstreetmap.josm.data.projection.datum.WGS84Datum; import org.openstreetmap.josm.data.projection.proj.ICentralMeridianProvider; +import org.openstreetmap.josm.data.projection.proj.IScaleFactorProvider; import org.openstreetmap.josm.data.projection.proj.Mercator; import org.openstreetmap.josm.data.projection.proj.Proj; @@ -274,4 +275,7 @@ this.k0 = parseDouble(s, Param.k_0.key); } + if (proj instanceof IScaleFactorProvider) { + this.k0 *= ((IScaleFactorProvider) proj).getScaleFactor(); + } s = parameters.get(Param.bounds.key); if (s != null) { Index: trunk/src/org/openstreetmap/josm/data/projection/Ellipsoid.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/Ellipsoid.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/Ellipsoid.java (revision 9565) @@ -132,4 +132,10 @@ /** + * if ellipsoid is spherical, i.e. the major and minor semiaxis are + * the same + */ + public final boolean spherical; + + /** * private constructur - use one of the create_* methods * @@ -139,6 +145,7 @@ * @param e2 first eccentricity squared * @param eb2 square of the second eccentricity - */ - private Ellipsoid(double a, double b, double e, double e2, double eb2) { + * @param sperical if the ellipsoid is sphere + */ + private Ellipsoid(double a, double b, double e, double e2, double eb2, boolean sperical) { this.a = a; this.b = b; @@ -146,4 +153,5 @@ this.e2 = e2; this.eb2 = eb2; + this.spherical = sperical; } @@ -159,5 +167,5 @@ double e = Math.sqrt(e2); double eb2 = e2 / (1.0 - e2); - return new Ellipsoid(a, b, e, e2, eb2); + return new Ellipsoid(a, b, e, e2, eb2, a == b); } @@ -173,5 +181,5 @@ double e = Math.sqrt(es); double eb2 = es / (1.0 - es); - return new Ellipsoid(a, b, e, es, eb2); + return new Ellipsoid(a, b, e, es, eb2, es == 0); } @@ -188,5 +196,5 @@ double e = Math.sqrt(e2); double eb2 = e2 / (1.0 - e2); - return new Ellipsoid(a, b, e, e2, eb2); + return new Ellipsoid(a, b, e, e2, eb2, f == 0); } @@ -334,5 +342,5 @@ return new LatLon(Math.toDegrees(lt), Math.toDegrees(lg)); } - + /** * convert ellipsoidal coordinates to cartesian coordinates Index: trunk/src/org/openstreetmap/josm/data/projection/Projections.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/Projections.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/Projections.java (revision 9565) @@ -89,8 +89,8 @@ registerBaseProjection("aea", AlbersEqualArea.class, "core"); registerBaseProjection("cass", CassiniSoldner.class, "core"); - registerBaseProjection("josm:smerc", Mercator.class, "core"); registerBaseProjection("laea", LambertAzimuthalEqualArea.class, "core"); registerBaseProjection("lcc", LambertConformalConic.class, "core"); registerBaseProjection("lonlat", LonLat.class, "core"); + registerBaseProjection("merc", Mercator.class, "core"); registerBaseProjection("omerc", ObliqueMercator.class, "core"); registerBaseProjection("somerc", SwissObliqueMercator.class, "core"); Index: trunk/src/org/openstreetmap/josm/data/projection/proj/AbstractProj.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/proj/AbstractProj.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/proj/AbstractProj.java (revision 9565) @@ -74,4 +74,10 @@ */ protected double e2; + + /** + * is ellipsoid spherical? + * @see Ellisoid.spherical + */ + protected boolean spherical; @Override @@ -79,4 +85,5 @@ e2 = params.ellps.e2; e = params.ellps.e; + spherical = params.ellps.spherical; // Compute constants for the mlfn double t; Index: trunk/src/org/openstreetmap/josm/data/projection/proj/IScaleFactorProvider.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/proj/IScaleFactorProvider.java (revision 9565) +++ trunk/src/org/openstreetmap/josm/data/projection/proj/IScaleFactorProvider.java (revision 9565) @@ -0,0 +1,21 @@ +// License: GPL. For details, see LICENSE file. +package org.openstreetmap.josm.data.projection.proj; + +/** + * A {@link Proj} implements this interface, if it derives the scale factor + * value from it's other input parameters. + * + * (Normally the scale factor is projection input parameter and the Proj + * class does not deal with it.) + * + * @see Proj + */ +public interface IScaleFactorProvider { + /** + * Get the scale factor. + * Will be multiplied by the scale factor parameter, if supplied by the user + * explicitly. + * @return the scale factor + */ + double getScaleFactor(); +} Index: trunk/src/org/openstreetmap/josm/data/projection/proj/Mercator.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/proj/Mercator.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/proj/Mercator.java (revision 9565) @@ -2,9 +2,4 @@ package org.openstreetmap.josm.data.projection.proj; -import static java.lang.Math.PI; -import static java.lang.Math.atan; -import static java.lang.Math.log; -import static java.lang.Math.sinh; -import static java.lang.Math.tan; import static org.openstreetmap.josm.tools.I18n.tr; @@ -13,7 +8,45 @@ /** - * Mercator Projection. + * Mercator Cylindrical Projection. The parallels and the meridians are straight lines and + * cross at right angles; this projection thus produces rectangular charts. The scale is true + * along the equator (by default) or along two parallels equidistant of the equator (if a scale + * factor other than 1 is used). This projection is used to represent areas close to the equator. + * It is also often used for maritime navigation because all the straight lines on the chart are + * loxodrome lines, i.e. a ship following this line would keep a constant azimuth on its + * compass. + *

+ * This implementation handles both the 1 and 2 stardard parallel cases. + * For 1 SP (EPSG code 9804), the line of contact is the equator. + * For 2 SP (EPSG code 9805) lines of contact are symmetrical + * about the equator. + *

+ * This class has been derived from the implementation of the Geotools project; + * git 8cbf52d, org.geotools.referencing.operation.projection.CassiniSoldner + * at the time of migration. + *

+ * References: + *

+ * + * @see Mercator projection on MathWorld + * @see "mercator_1sp" on RemoteSensing.org + * @see "mercator_2sp" on RemoteSensing.org + * + * @author André Gosselin + * @author Martin Desruisseaux (PMO, IRD) + * @author Rueben Schulz + * @author Simone Giannecchini */ -public class Mercator implements Proj { +public class Mercator extends AbstractProj implements IScaleFactorProvider { + /** + * Maximum difference allowed when comparing real numbers. + */ + private static final double EPSILON = 1E-6; + + protected double scaleFactor; @Override @@ -24,19 +57,56 @@ @Override public String getProj4Id() { - return "josm:smerc"; // "merc" is ellipsoidal Mercator projection in PROJ.4 + return "merc"; } @Override public void initialize(ProjParameters params) throws ProjectionConfigurationException { + super.initialize(params); + scaleFactor = 1; + if (params.lat_ts != null) { + /* + * scaleFactor is not a parameter in the 2 SP case and is computed from + * the standard parallel. + */ + double standardParallel = Math.toRadians(params.lat_ts); + if (spherical) { + scaleFactor *= Math.cos(standardParallel); + } else { + scaleFactor *= msfn(Math.sin(standardParallel), Math.cos(standardParallel)); + } + } + /* + * A correction that allows us to employs a latitude of origin that is not + * correspondent to the equator. See Snyder and al. for reference, page 47. + */ + if (params.lat0 != null) { + final double lat0 = Math.toRadians(params.lat0); + final double sinPhi = Math.sin(lat0); + scaleFactor *= (Math.cos(lat0) / (Math.sqrt(1 - e2 * sinPhi * sinPhi))); + } } @Override - public double[] project(double lat_rad, double lon_rad) { - return new double[] {lon_rad, log(tan(PI/4 + lat_rad/2))}; + public double[] project(double y, double x) { + if (Math.abs(y) > (Math.PI/2 - EPSILON)) { + return new double[] {0, 0}; // this is an error and should be handled somehow + } + if (spherical) { + y = Math.log(Math.tan(Math.PI/4 + 0.5*y)); + } else { + y = -Math.log(tsfn(y, Math.sin(y))); + } + return new double[] {x, y}; } @Override - public double[] invproject(double east, double north) { - return new double[] {atan(sinh(north)), east}; + public double[] invproject(double x, double y) { + if (spherical) { + y = Math.PI/2 - 2.0*Math.atan(Math.exp(-y)); + } else { + y = Math.exp(-y); + y = cphi2(y); + } + return new double[] {y, x}; } @@ -45,3 +115,8 @@ return new Bounds(-89, -180, 89, 180, false); } + + @Override + public double getScaleFactor() { + return scaleFactor; + } } Index: trunk/src/org/openstreetmap/josm/data/projection/proj/ProjParameters.java =================================================================== --- trunk/src/org/openstreetmap/josm/data/projection/proj/ProjParameters.java (revision 9564) +++ trunk/src/org/openstreetmap/josm/data/projection/proj/ProjParameters.java (revision 9565) @@ -15,5 +15,5 @@ public Double lat2; - // Polar Stereographic + // Polar Stereographic and Mercator public Double lat_ts;