postgis/lwgeom_transform.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 (C) 2001-2003 Refractions Research Inc.
 *
 **********************************************************************/


#include "postgres.h"
#include "fmgr.h"

#include "../postgis_config.h"
#include "liblwgeom.h"
#include "lwgeom_transform.h"


Datum transform(PG_FUNCTION_ARGS);
Datum transform_geom(PG_FUNCTION_ARGS);
Datum postgis_proj_version(PG_FUNCTION_ARGS);



PG_FUNCTION_INFO_V1(transform);
Datum transform(PG_FUNCTION_ARGS)
{
        GSERIALIZED *geom;
        GSERIALIZED *result=NULL;
        LWGEOM *lwgeom;
        projPJ input_pj, output_pj;
        int32 output_srid, input_srid;

        output_srid = PG_GETARG_INT32(1);
        if (output_srid == SRID_UNKNOWN)
        {
                elog(ERROR,"%d is an invalid target SRID",SRID_UNKNOWN);
                PG_RETURN_NULL();
        }

        geom = PG_GETARG_GSERIALIZED_P_COPY(0);
        input_srid = gserialized_get_srid(geom);
        if ( input_srid == SRID_UNKNOWN )
        {
                PG_FREE_IF_COPY(geom, 0);
                elog(ERROR,"Input geometry has unknown (%d) SRID",SRID_UNKNOWN);
                PG_RETURN_NULL();
        }

        /*
         * If input SRID and output SRID are equal, return geometry
         * without transform it
         */
        if ( input_srid == output_srid )
                PG_RETURN_POINTER(PG_GETARG_DATUM(0));

        if ( GetProjectionsUsingFCInfo(fcinfo, input_srid, output_srid, &input_pj, &output_pj) == LW_FAILURE )
        {
                PG_FREE_IF_COPY(geom, 0);
                elog(ERROR,"Failure reading projections from spatial_ref_sys.");
                PG_RETURN_NULL();
        }

        /* now we have a geometry, and input/output PJ structs. */
        lwgeom = lwgeom_from_gserialized(geom);
        lwgeom_transform(lwgeom, input_pj, output_pj);
        lwgeom->srid = output_srid;

        /* Re-compute bbox if input had one (COMPUTE_BBOX TAINTING) */
        if ( lwgeom->bbox )
        {
                lwgeom_drop_bbox(lwgeom);
                lwgeom_add_bbox(lwgeom);
        }

        result = geometry_serialize(lwgeom);
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom, 0);

        PG_RETURN_POINTER(result); /* new geometry */
}

PG_FUNCTION_INFO_V1(transform_geom);
Datum transform_geom(PG_FUNCTION_ARGS)
{
        GSERIALIZED *geom;
        GSERIALIZED *result=NULL;
        LWGEOM *lwgeom;
        projPJ input_pj, output_pj;
        char *input_proj4, *output_proj4;
        text *input_proj4_text;
        text *output_proj4_text;
        int32 result_srid ;
        char *pj_errstr;

        result_srid = PG_GETARG_INT32(3);
        geom = PG_GETARG_GSERIALIZED_P_COPY(0);

        /* Set the search path if we haven't already */
        SetPROJ4LibPath();

        /* Read the arguments */
        input_proj4_text  = (PG_GETARG_TEXT_P(1));
        output_proj4_text = (PG_GETARG_TEXT_P(2));

        /* Convert from text to cstring for libproj */
        input_proj4 = text2cstring(input_proj4_text);
        output_proj4 = text2cstring(output_proj4_text);

        /* make input and output projection objects */
        input_pj = lwproj_from_string(input_proj4);
        if ( input_pj == NULL )
        {
                pj_errstr = pj_strerrno(*pj_get_errno_ref());
                if ( ! pj_errstr ) pj_errstr = "";

                /* we need this for error reporting */
                /* pfree(input_proj4); */
                pfree(output_proj4);
                pfree(geom);

                elog(ERROR,
                    "transform_geom: could not parse proj4 string '%s' %s",
                    input_proj4, pj_errstr);
                PG_RETURN_NULL();
        }
        pfree(input_proj4);

        output_pj = lwproj_from_string(output_proj4);

        if ( output_pj == NULL )
        {
                pj_errstr = pj_strerrno(*pj_get_errno_ref());
                if ( ! pj_errstr ) pj_errstr = "";

                /* we need this for error reporting */
                /* pfree(output_proj4); */
                pj_free(input_pj);
                pfree(geom);

                elog(ERROR,
                        "transform_geom: couldn't parse proj4 output string: '%s': %s",
                        output_proj4, pj_errstr);
                PG_RETURN_NULL();
        }
        pfree(output_proj4);

        /* now we have a geometry, and input/output PJ structs. */
        lwgeom = lwgeom_from_gserialized(geom);
        lwgeom_transform(lwgeom, input_pj, output_pj);
        lwgeom->srid = result_srid;

        /* clean up */
        pj_free(input_pj);
        pj_free(output_pj);

        /* Re-compute bbox if input had one (COMPUTE_BBOX TAINTING) */
        if ( lwgeom->bbox )
        {
                lwgeom_drop_bbox(lwgeom);
                lwgeom_add_bbox(lwgeom);
        }

        result = geometry_serialize(lwgeom);

        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom, 0);

        PG_RETURN_POINTER(result); /* new geometry */
}


PG_FUNCTION_INFO_V1(postgis_proj_version);
Datum postgis_proj_version(PG_FUNCTION_ARGS)
{
        const char *ver = pj_get_release();
        text *result = cstring2text(ver);
        PG_RETURN_POINTER(result);
}