| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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. |
| */ |
| |
| /** |
| * Extensions to referencing services as wrapper around the C/C++ {@literal Proj.4} library. |
| * Current version wraps only referencing services, but future versions are expected to wrap more GDAL functionalities. |
| * Unless otherwise specified, this optional module requires the native (C/C++) <a href="http://proj.osgeo.org/">Proj.4</a> |
| * library to be installed on the local machine. This package allows to: |
| * <ul> |
| * <li>{@linkplain org.apache.sis.storage.gdal.Proj4#createCRS Create a Coordinate Reference System instance from a Proj.4 definition string}.</li> |
| * <li>Conversely, {@linkplain org.apache.sis.storage.gdal.Proj4#definition get a Proj.4 definition string from a Coordinate Reference System}.</li> |
| * <li>{@linkplain org.apache.sis.storage.gdal.Proj4#createOperation Create a coordinate operation backed by Proj.4 between two arbitrary CRS}.</li> |
| * </ul> |
| * |
| * Note that Apache SIS provides its own map projection engine in pure Java, so this module is usually not needed. |
| * This module is useful when a map projection is not yet available in Apache SIS, or when an application needs to |
| * reproduce the exact same numerical results than Proj.4. But some Apache SIS features like |
| * {@linkplain org.apache.sis.referencing.operation.transform.AbstractMathTransform#derivative transform derivatives} |
| * are not available through the Proj.4 wrappers. |
| * |
| * <p>When this optional module is available, the {@link org.apache.sis.referencing.CRS#forCode CRS.forCode(String)} |
| * method accepts Proj.4 definition strings prefixed by {@code "Proj4::"}. Example:</p> |
| * |
| * {@preformat java |
| * CoordinateReferenceSystem crs = CRS.forCode("Proj4::+init=epsg:3395"); |
| * } |
| * |
| * Calls to {@link org.apache.sis.referencing.CRS#findOperation CRS.findOperation(…)} will delegate the coordinate |
| * transformation to Proj.4 if {@code sourceCRS} and {@code targetCRS} were both obtained from a code in {@code "Proj4"} |
| * namespace or by a method in this package. Otherwise, Apache SIS will use its own referencing engine. |
| * The backing referencing engine can be seen by printing the {@code MathTransform}: |
| * a transform backed by Proj.4 have a <cite>Well Known Text 1</cite> representation like below: |
| * |
| * {@preformat wkt |
| * PARAM_MT["pj_transform", |
| * PARAMETER["srcdefn", "+proj=…"], |
| * PARAMETER["dstdefn", "+proj=…"]] |
| * } |
| * |
| * <h2>Note on Proj.4 definition strings</h2> |
| * Proj.4 unconditionally requires 3 letters for the {@code "+axis="} parameter — for example {@code "neu"} for |
| * <cite>North</cite>, <cite>East</cite> and <cite>Up</cite> respectively — regardless the number of dimensions |
| * in the CRS to create. Apache SIS makes the vertical direction optional in order to specify whether the CRS to |
| * create shall contain a vertical axis or not: |
| * |
| * <ul> |
| * <li>If the vertical direction is present (as in {@code "neu"}), a three-dimensional CRS is created.</li> |
| * <li>If the vertical direction is absent (as in {@code "ne"}), a two-dimensional CRS is created.</li> |
| * </ul> |
| * |
| * <div class="note"><b>Examples:</b> |
| * <ul> |
| * <li>{@code "+init=epsg:4326"} (<strong>not</strong> equivalent to the standard EPSG::4326 definition)</li> |
| * <li>{@code "+proj=latlong +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0"} (default to two-dimensional CRS)</li> |
| * <li>{@code "+proj=latlon +a=6378137.0 +b=6356752.314245179 +pm=0.0 +axis=ne"} (explicitly two-dimensional)</li> |
| * <li>{@code "+proj=latlon +a=6378137.0 +b=6356752.314245179 +pm=0.0 +axis=neu"} (three-dimensional)</li> |
| * </ul> |
| * </div> |
| * |
| * <b>Warning:</b> despite the {@code "epsg"} word, coordinate reference systems created by {@code "+init=epsg:"} |
| * syntax are not necessarily compliant with EPSG definitions. In particular, the axis order is often different. |
| * Units of measurement may also differ. |
| * |
| * <h2>Installation</h2> |
| * The Proj.4 library needs to be reachable on a platform-dependent library path. |
| * For example the operating system may search in {@code /usr/lib}, {@code /opt/local/lib} and other directories. |
| * One of those directories shall contain the {@code proj} or {@code libproj} file with platform-specific suffix |
| * (e.g. {@code .so}, {@code .dylib} or {@code .dll}). |
| * An easy way to install the library in appropriate directory is to use the package manager provided by the platform. |
| * |
| * @author Martin Desruisseaux (Geomatys) |
| * @version 0.8 |
| * @since 0.8 |
| * @module |
| */ |
| package org.apache.sis.storage.gdal; |
