lwout_kml.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2006 Corporacion Autonoma Regional de Santander
 * Copyright 2010 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 **********************************************************************/


#include "liblwgeom_internal.h"
#include "stringbuffer.h"

static int lwgeom_to_kml2_sb(const LWGEOM *geom, int precision, const char *prefix, stringbuffer_t *sb);
static int lwpoint_to_kml2_sb(const LWPOINT *point, int precision, const char *prefix, stringbuffer_t *sb);
static int lwline_to_kml2_sb(const LWLINE *line, int precision, const char *prefix, stringbuffer_t *sb);
static int lwpoly_to_kml2_sb(const LWPOLY *poly, int precision, const char *prefix, stringbuffer_t *sb);
static int lwcollection_to_kml2_sb(const LWCOLLECTION *col, int precision, const char *prefix, stringbuffer_t *sb);
static int ptarray_to_kml2_sb(const POINTARRAY *pa, int precision, stringbuffer_t *sb);

/*
* KML 2.2.0
*/

/* takes a GEOMETRY and returns a KML representation */
char*
lwgeom_to_kml2(const LWGEOM *geom, int precision, const char *prefix)
{
        stringbuffer_t *sb;
        int rv;
        char *kml;

        /* Can't do anything with empty */
        if( lwgeom_is_empty(geom) )
                return NULL;

        sb = stringbuffer_create();
        rv = lwgeom_to_kml2_sb(geom, precision, prefix, sb);

        if ( rv == LW_FAILURE )
        {
                stringbuffer_destroy(sb);
                return NULL;
        }

        kml = stringbuffer_getstringcopy(sb);
        stringbuffer_destroy(sb);

        return kml;
}

static int
lwgeom_to_kml2_sb(const LWGEOM *geom, int precision, const char *prefix, stringbuffer_t *sb)
{
        switch (geom->type)
        {
        case POINTTYPE:
                return lwpoint_to_kml2_sb((LWPOINT*)geom, precision, prefix, sb);

        case LINETYPE:
                return lwline_to_kml2_sb((LWLINE*)geom, precision, prefix, sb);

        case POLYGONTYPE:
                return lwpoly_to_kml2_sb((LWPOLY*)geom, precision, prefix, sb);

        case MULTIPOINTTYPE:
        case MULTILINETYPE:
        case MULTIPOLYGONTYPE:
                return lwcollection_to_kml2_sb((LWCOLLECTION*)geom, precision, prefix, sb);

        default:
                lwerror("lwgeom_to_kml2: '%s' geometry type not supported", lwtype_name(geom->type));
                return LW_FAILURE;
        }
}

static int
ptarray_to_kml2_sb(const POINTARRAY *pa, int precision, stringbuffer_t *sb)
{
        int i, j;
        int dims = FLAGS_GET_Z(pa->flags) ? 3 : 2;
        POINT4D pt;
        double *d;

        for ( i = 0; i < pa->npoints; i++ )
        {
                getPoint4d_p(pa, i, &pt);
                d = (double*)(&pt);
                if ( i ) stringbuffer_append(sb," ");
                for (j = 0; j < dims; j++)
                {
                        if ( j ) stringbuffer_append(sb,",");
                        if( fabs(d[j]) < OUT_MAX_DOUBLE )
                        {
                                if ( stringbuffer_aprintf(sb, "%.*f", precision, d[j]) < 0 ) return LW_FAILURE;
                        }
                        else
                        {
                                if ( stringbuffer_aprintf(sb, "%g", d[j]) < 0 ) return LW_FAILURE;
                        }
                        stringbuffer_trim_trailing_zeroes(sb);
                }
        }
        return LW_SUCCESS;
}


static int
lwpoint_to_kml2_sb(const LWPOINT *point, int precision, const char *prefix, stringbuffer_t *sb)
{
        /* Open point */
        if ( stringbuffer_aprintf(sb, "<%sPoint><%scoordinates>", prefix, prefix) < 0 ) return LW_FAILURE;
        /* Coordinate array */
        if ( ptarray_to_kml2_sb(point->point, precision, sb) == LW_FAILURE ) return LW_FAILURE;
        /* Close point */
        if ( stringbuffer_aprintf(sb, "</%scoordinates></%sPoint>", prefix, prefix) < 0 ) return LW_FAILURE;
        return LW_SUCCESS;
}

static int
lwline_to_kml2_sb(const LWLINE *line, int precision, const char *prefix, stringbuffer_t *sb)
{
        /* Open linestring */
        if ( stringbuffer_aprintf(sb, "<%sLineString><%scoordinates>", prefix, prefix) < 0 ) return LW_FAILURE;
        /* Coordinate array */
        if ( ptarray_to_kml2_sb(line->points, precision, sb) == LW_FAILURE ) return LW_FAILURE;
        /* Close linestring */
        if ( stringbuffer_aprintf(sb, "</%scoordinates></%sLineString>", prefix, prefix) < 0 ) return LW_FAILURE;

        return LW_SUCCESS;
}

static int
lwpoly_to_kml2_sb(const LWPOLY *poly, int precision, const char *prefix, stringbuffer_t *sb)
{
        int i, rv;

        /* Open polygon */
        if ( stringbuffer_aprintf(sb, "<%sPolygon>", prefix) < 0 ) return LW_FAILURE;
        for ( i = 0; i < poly->nrings; i++ )
        {
                /* Inner or outer ring opening tags */
                if( i )
                        rv = stringbuffer_aprintf(sb, "<%sinnerBoundaryIs><%sLinearRing><%scoordinates>", prefix, prefix, prefix);
                else
                        rv = stringbuffer_aprintf(sb, "<%souterBoundaryIs><%sLinearRing><%scoordinates>", prefix, prefix, prefix);
                if ( rv < 0 ) return LW_FAILURE;

                /* Coordinate array */
                if ( ptarray_to_kml2_sb(poly->rings[i], precision, sb) == LW_FAILURE ) return LW_FAILURE;

                /* Inner or outer ring closing tags */
                if( i )
                        rv = stringbuffer_aprintf(sb, "</%scoordinates></%sLinearRing></%sinnerBoundaryIs>", prefix, prefix, prefix);
                else
                        rv = stringbuffer_aprintf(sb, "</%scoordinates></%sLinearRing></%souterBoundaryIs>", prefix, prefix, prefix);
                if ( rv < 0 ) return LW_FAILURE;
        }
        /* Close polygon */
        if ( stringbuffer_aprintf(sb, "</%sPolygon>", prefix) < 0 ) return LW_FAILURE;

        return LW_SUCCESS;
}

static int
lwcollection_to_kml2_sb(const LWCOLLECTION *col, int precision, const char *prefix, stringbuffer_t *sb)
{
        int i, rv;

        /* Open geometry */
        if ( stringbuffer_aprintf(sb, "<%sMultiGeometry>", prefix) < 0 ) return LW_FAILURE;
        for ( i = 0; i < col->ngeoms; i++ )
        {
                rv = lwgeom_to_kml2_sb(col->geoms[i], precision, prefix, sb);
                if ( rv == LW_FAILURE ) return LW_FAILURE;
        }
        /* Close geometry */
        if ( stringbuffer_aprintf(sb, "</%sMultiGeometry>", prefix) < 0 ) return LW_FAILURE;

        return LW_SUCCESS;
}