PDFlib

geospatial_pdf/georeferenced_image

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package com.pdflib.cookbook.pdflib.geospatial;


import com.pdflib.pdflib;

import com.pdflib.PDFlibException;


/**

 * This topic attaches geospatial reference data to an image. This works fine

 * in Acrobat, but is not currently supported in the Avenza PDF Maps app which

 * supports only geospatial reference data attached to the whole page.

 * In order to create georeferenced PDF for use with Avenza use the method

 * demonstrated in the georeferenced_image Cookbook topic.

 *

 * Sample map and coordinates:

 * We use a map from www.openstreetmap.com; the geospatial coordinates of the

 * image edges were also provided by that Web site.

 * The coordinate system is WGS84 which is also used for GPS.

 *

 * Required software: PDFlib/PDFlib+PDI/PPS 9

 * Required data: image file and associated geospatial reference information

 *

 * @version $Id: georeferenced_image.java,v 1.1 2016/06/28 13:36:35 stm Exp $

 */

class georeferenced_image {

    public static void main(String argv[]) {

        /* This is where the data files are. Adjust if necessary. */

        final String searchpath = "../input";

        final String outfile = "georeferenced_image.pdf";


        String georefoptlist;

        pdflib p = null;

        int image;

        final String imagefile = "munich.png";

        int exitcode = 0;


        /* WKT for plain latitude/longitude values in WGS84 */

        final String georef = "worldsystem={type=geographic wkt={"

            + "GEOGCS[\"WGS 84\","

            + "  DATUM[\"WGS_1984\", SPHEROID[\"WGS 84\", 6378137,298.257223563]],"

            + "  PRIMEM[\"Greenwich\", 0.0],"

            + "  UNIT[\"Degree\", 0.01745329251994328]]"

            + "}} linearunit=M areaunit=SQM angularunit=degree";


        /* world coordinates of the image (in degrees) */

        double worldpoints[] = {

            48.145, /* latitude of top edge */

            11.565, /* longitude of left edge */

            11.59, /* longitude of right edge */

            48.13 /* latitude of bottom edge */

        };


        try {

            p = new pdflib();


            p.set_option("searchpath={" + searchpath + "}");


            /* This means we must check return values of load_font() etc. */

            p.set_option("errorpolicy=return");


            /* Start the document */

            if (p.begin_document(outfile, "compatibility=1.7ext3") == -1) {

                throw new Exception("Error: " + p.get_errmsg());

            }


            p.set_info("Creator", "PDFlib starter sample");

            p.set_info("Title", "georeferenced_image $Revision: 1.1 $");


            /* Generate georeference option list */

            /*

             * Use the four corners as reference points; (0,0)=lower left etc.

             */

            georefoptlist = "georeference={" + georef

                + " mappoints={0 0  1 0  1 1  0 1} ";


            georefoptlist += "worldpoints={";


            /* lower left corner */

            georefoptlist += worldpoints[3] + " " + worldpoints[1] + " ";

            /* lower right corner */

            georefoptlist += worldpoints[3] + " " + worldpoints[2] + " ";

            /* upper right corner */

            georefoptlist += worldpoints[0] + " " + worldpoints[2] + " ";

            /* upper left corner */

            georefoptlist += worldpoints[0] + " " + worldpoints[1] + " ";


            georefoptlist += "} }";


            /* Load the image with geospatial reference attached */

            image = p.load_image("auto", imagefile, georefoptlist);

            if (image == -1) {

                throw new Exception("Error: " + p.get_errmsg());

            }


            p.begin_page_ext(0, 0, "width=a4.width height=a4.height");


            /* Create caption */

            p.fit_textline("Map with geospatial reference information", 50, 700,

                "fontname=LuciduxSans-Oblique encoding=winansi fontsize=18");


            /* Place the map on the page */

            p.fit_image(image, 50, 50, "boxsize={500 600} fitmethod=meet");


            p.end_page_ext("");


            p.end_document("");

        }

        catch (PDFlibException e) {

            System.err.print("PDFlib exception occurred:\n");

            System.err.print("[" + e.get_errnum() + "] " + e.get_apiname()

                + ": " + e.get_errmsg() + "\n");

            exitcode = 1;

        }

        catch (Exception e) {

            System.err.println(e.getMessage());

            exitcode = 1;

        }

        finally {

            if (p != null) {

                p.delete();

            }

            System.exit(exitcode);

        }

    }

}