rt_raster_within_distance()

rt_errorstate rt_raster_within_distance	(	rt_raster	rast1,
		int	nband1,
		rt_raster	rast2,
		int	nband2,
		double	distance,
		int *	dwithin
	)

Return ES_ERROR if error occurred in function.

Parameter dwithin returns non-zero if rast1 is within the specified distance of rast2

Parameters

rast1	: the first raster whose band will be tested
nband1	: the 0-based band of raster rast1 to use if value is less than zero, bands are ignored. if nband1 gte zero, nband2 must be gte zero
rast2	: the second raster whose band will be tested
nband2	: the 0-based band of raster rast2 to use if value is less than zero, bands are ignored if nband2 gte zero, nband1 must be gte zero
dwithin	: non-zero value if rast1 is within the specified distance of rast2

Returns

ES_NONE if success, ES_ERROR if error

Definition at line 460 of file rt_spatial_relationship.c.

  {
        LWMPOLY *surface = NULL;
        LWGEOM *surface1 = NULL;
        LWGEOM *surface2 = NULL;
        double mindist = 0;
 
        RASTER_DEBUG(3, "Starting");
 
        assert(NULL != rast1);
        assert(NULL != rast2);
        assert(NULL != dwithin);
 
        if (nband1 < 0 && nband2 < 0) {
                nband1 = -1;
                nband2 = -1;
        }
        else {
                assert(nband1 >= 0 && nband1 < rt_raster_get_num_bands(rast1));
                assert(nband2 >= 0 && nband2 < rt_raster_get_num_bands(rast2));
        }
 
        /* initialize to zero, false result */
        *dwithin = 0;
 
        /* same srid */
        if (rt_raster_get_srid(rast1) != rt_raster_get_srid(rast2)) {
                rterror("rt_raster_distance_within: The two rasters provided have different SRIDs");
                return ES_ERROR;
        }
 
        /* distance cannot be less than zero */
        if (distance < 0) {
                rterror("rt_raster_distance_within: Distance cannot be less than zero");
                return ES_ERROR;
        }
 
        /* get LWMPOLY of each band */
        if (rt_raster_surface(rast1, nband1, &surface) != ES_NONE) {
                rterror("rt_raster_distance_within: Could not get surface of the specified band from the first raster");
                return ES_ERROR;
        }
        surface1 = lwmpoly_as_lwgeom(surface);
 
        if (rt_raster_surface(rast2, nband2, &surface) != ES_NONE) {
                rterror("rt_raster_distance_within: Could not get surface of the specified band from the second raster");
                lwgeom_free(surface1);
                return ES_ERROR;
        }
        surface2 = lwmpoly_as_lwgeom(surface);
 
        /* either surface is NULL, test is false */
        if (surface1 == NULL || surface2 == NULL) {
                if (surface1 != NULL) lwgeom_free(surface1);
                if (surface2 != NULL) lwgeom_free(surface2);
                return ES_NONE;
        }
 
        /* get the min distance between the two surfaces */
        mindist = lwgeom_mindistance2d_tolerance(surface1, surface2, distance);
 
        lwgeom_free(surface1);
        lwgeom_free(surface2);
 
        /* if distance >= mindist, true */
        if (FLT_EQ(mindist, distance) || distance > mindist)
                *dwithin = 1;
 
        RASTER_DEBUGF(3, "(mindist, distance) = (%f, %f, %d)", mindist, distance, *dwithin);
 
        return ES_NONE;
}

References distance(), ES_ERROR, ES_NONE, FLT_EQ, lwgeom_free(), lwgeom_mindistance2d_tolerance(), lwmpoly_as_lwgeom(), RASTER_DEBUG, RASTER_DEBUGF, rt_raster_get_num_bands(), rt_raster_get_srid(), rt_raster_surface(), and rterror().

Referenced by RASTER_dwithin(), and test_raster_within_distance().

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