rtpg_getSR()

char* rtpg_getSR

(

int

srid

)

Definition at line 282 of file rtpg_internal.c.

References MAX_INT_CHARLEN, POSTGIS_RT_DEBUGF, rt_util_gdal_supported_sr(), rtgdalraster::sql, and TRUE.

Referenced by RASTER_asGDALRaster(), RASTER_asRaster(), and RASTER_GDALWarp().

                     {
        int i = 0;
        int len = 0;
        char *sql = NULL;
        int spi_result;
        TupleDesc tupdesc;
        SPITupleTable *tuptable = NULL;
        HeapTuple tuple;
        char *tmp = NULL;
        char *srs = NULL;

/*
SELECT
        CASE
                WHEN (upper(auth_name) = 'EPSG' OR upper(auth_name) = 'EPSGA') AND length(COALESCE(auth_srid::text, '')) > 0
                        THEN upper(auth_name) || ':' || auth_srid
                WHEN length(COALESCE(auth_name, '') || COALESCE(auth_srid::text, '')) > 0
                        THEN COALESCE(auth_name, '') || COALESCE(auth_srid::text, '')
                ELSE ''
        END,
        proj4text,
        srtext
FROM spatial_ref_sys
WHERE srid = X
LIMIT 1
*/

        len = sizeof(char) * (strlen("SELECT CASE WHEN (upper(auth_name) = 'EPSG' OR upper(auth_name) = 'EPSGA') AND length(COALESCE(auth_srid::text, '')) > 0 THEN upper(auth_name) || ':' || auth_srid WHEN length(COALESCE(auth_name, '') || COALESCE(auth_srid::text, '')) > 0 THEN COALESCE(auth_name, '') || COALESCE(auth_srid::text, '') ELSE '' END, proj4text, srtext FROM spatial_ref_sys WHERE srid =  LIMIT 1") + MAX_INT_CHARLEN + 1);
        sql = (char *) palloc(len);
        if (NULL == sql) {
                elog(ERROR, "rtpg_getSR: Could not allocate memory for sql\n");
                return NULL;
        }

        spi_result = SPI_connect();
        if (spi_result != SPI_OK_CONNECT) {
                pfree(sql);
                elog(ERROR, "rtpg_getSR: Could not connect to database using SPI\n");
                return NULL;
        }

        /* execute query */
        snprintf(sql, len, "SELECT CASE WHEN (upper(auth_name) = 'EPSG' OR upper(auth_name) = 'EPSGA') AND length(COALESCE(auth_srid::text, '')) > 0 THEN upper(auth_name) || ':' || auth_srid WHEN length(COALESCE(auth_name, '') || COALESCE(auth_srid::text, '')) > 0 THEN COALESCE(auth_name, '') || COALESCE(auth_srid::text, '') ELSE '' END, proj4text, srtext FROM spatial_ref_sys WHERE srid = %d LIMIT 1", srid);
        POSTGIS_RT_DEBUGF(4, "SRS query: %s", sql);
        spi_result = SPI_execute(sql, TRUE, 0);
        SPI_pfree(sql);
        if (spi_result != SPI_OK_SELECT || SPI_tuptable == NULL || SPI_processed != 1) {
                if (SPI_tuptable) SPI_freetuptable(tuptable);
                SPI_finish();
                elog(ERROR, "rtpg_getSR: Cannot find SRID (%d) in spatial_ref_sys", srid);
                return NULL;
        }

        tupdesc = SPI_tuptable->tupdesc;
        tuptable = SPI_tuptable;
        tuple = tuptable->vals[0];

        /* which column to use? */
        for (i = 1; i < 4; i++) {
                tmp = SPI_getvalue(tuple, tupdesc, i);

                /* value AND GDAL supports this SR */
                if (
                        SPI_result != SPI_ERROR_NOATTRIBUTE &&
                        SPI_result != SPI_ERROR_NOOUTFUNC &&
                        tmp != NULL &&
                        strlen(tmp) &&
                        rt_util_gdal_supported_sr(tmp)
                ) {
                        POSTGIS_RT_DEBUGF(4, "Value for column %d is %s", i, tmp);

                        len = strlen(tmp) + 1;
                        srs = SPI_palloc(sizeof(char) * len);
                        if (NULL == srs) {
                                pfree(tmp);
                                if (SPI_tuptable) SPI_freetuptable(tuptable);
                                SPI_finish();
                                elog(ERROR, "rtpg_getSR: Could not allocate memory for spatial reference text\n");
                                return NULL;
                        }
                        strncpy(srs, tmp, len);
                        pfree(tmp);

                        break;
                }

                if (tmp != NULL)
                        pfree(tmp);
                continue;
        }

        if (SPI_tuptable) SPI_freetuptable(tuptable);
        SPI_finish();

        /* unable to get SR info */
        if (srs == NULL) {
                if (SPI_tuptable) SPI_freetuptable(tuptable);
                SPI_finish();
                elog(ERROR, "rtpg_getSR: Could not find a viable spatial reference for SRID (%d)", srid);
                return NULL;
        }

        return srs;
}

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