rt_raster_copy_to_geometry()

rt_errorstate rt_raster_copy_to_geometry	(	rt_raster	raster,
		uint32_t	bandnum,
		char	dim,
		rt_resample_type	resample,
		const LWGEOM *	lwgeom_in,
		LWGEOM **	lwgeom_out
	)

Copy values from a raster to the points on a geometry using the requested interpolation type.

and selected interpolation.

Parameters

raster	: the raster to read for values
bandnum	: the band number to read from
dim	: the geometry dimension to copy values into 'Z' or 'M'
resample	: algorithm for reading raster (nearest or bilinear)
lwgeom_in	: the input geometry
lwgeom_out	: pointer for the output geometry

Returns

ES_ERROR on error, otherwise ES_NONE

Definition at line 1492 of file rt_raster.c.

{
        int has_z = lwgeom_has_z(lwgeom_in);
        int has_m = lwgeom_has_m(lwgeom_in);
        LWGEOM *lwgeom;
        LWPOINTITERATOR* it;
        POINT4D p;
        double igt[6] = {0};
        rt_errorstate err;
        rt_band band = NULL;
        double nodatavalue = 0.0;
 
        /* Get the band reference and read the nodatavalue */
        band = rt_raster_get_band(raster, bandnum);
        if (!band) {
                rterror("unable to read requested band");
                return ES_ERROR;
        }
        rt_band_get_nodata(band, &nodatavalue);
 
        /* Fluff up geometry to have space for our new dimension */
        if (dim == 'z') {
                if (has_z)
                        lwgeom = lwgeom_clone(lwgeom_in);
                else if (has_m)
                        lwgeom = lwgeom_force_4d(lwgeom_in, nodatavalue, nodatavalue);
                else
                        lwgeom = lwgeom_force_3dz(lwgeom_in, nodatavalue);
        }
        else if (dim == 'm') {
                if (has_m)
                        lwgeom = lwgeom_clone(lwgeom_in);
                if (has_z)
                        lwgeom = lwgeom_force_4d(lwgeom_in, nodatavalue, nodatavalue);
                else
                        lwgeom = lwgeom_force_3dm(lwgeom_in, nodatavalue);
        }
        else {
                rterror("unknown value for dim");
                return ES_ERROR;
        }
 
        /* Read every point in the geometry */
        it = lwpointiterator_create_rw(lwgeom);
        while (lwpointiterator_has_next(it))
        {
                int nodata;
                double xr, yr, value;
                lwpointiterator_peek(it, &p);
 
                /* Convert X/Y world coordinates into raster coordinates */
                err = rt_raster_geopoint_to_rasterpoint(raster, p.x, p.y, &xr, &yr, igt);
                if (err != ES_NONE) continue;
 
                /* Read the raster value for this point */
                err = rt_band_get_pixel_resample(
                        band,
                        xr, yr,
                        resample,
                        &value, &nodata
                );
 
                if (err != ES_NONE) {
                        value = NAN;
                }
 
                /* Copy in the raster value */
                if (dim == 'z')
                        p.z = value;
                if (dim == 'm')
                        p.m = value;
 
                lwpointiterator_modify_next(it, &p);
        }
        lwpointiterator_destroy(it);
 
        if (lwgeom_out)
                *lwgeom_out = lwgeom;
        return ES_NONE;
}

References ovdump::band, ES_ERROR, ES_NONE, lwgeom_clone(), lwgeom_force_3dm(), lwgeom_force_3dz(), lwgeom_force_4d(), lwgeom_has_m(), lwgeom_has_z(), lwpointiterator_create_rw(), lwpointiterator_destroy(), lwpointiterator_has_next(), lwpointiterator_modify_next(), lwpointiterator_peek(), POINT4D::m, NAN, rtrowdump::raster, rt_band_get_nodata(), rt_band_get_pixel_resample(), rt_raster_geopoint_to_rasterpoint(), rt_raster_get_band(), rterror(), genraster::value, POINT4D::x, POINT4D::y, and POINT4D::z.

Referenced by RASTER_getGeometryValues().

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