RASTER_reclass_exact()

Datum RASTER_reclass_exact

(

PG_FUNCTION_ARGS

)

Definition at line 4013 of file rtpg_mapalgebra.c.

                                             {
        rt_pgraster *pgraster = NULL;
        rt_pgraster *pgrtn = NULL;
        rt_raster raster = NULL;
        rt_band band = NULL;
        rt_band newband = NULL;
        uint32_t bandnum = 0, numbands = 0;
        ArrayType *arraysrc, *arraydst;
        bool hasnodata = false;
        double nodataval = 0.0;
        text *pixeltype = NULL;
        uint32_t szsrc, szdst;
        ArrayIterator itersrc, iterdst;
        Datum dsrc, ddst;
        bool nullsrc, nulldst;
        rt_reclassmap reclassmap;
        rt_pixtype pixtypsrc, pixtypdst;
 
        /* Check null on all arguments since function is not strict */
        if (PG_ARGISNULL(0) || PG_ARGISNULL(1) || PG_ARGISNULL(2) || PG_ARGISNULL(3) || PG_ARGISNULL(4))
                PG_RETURN_NULL();
 
        /* Read SQL arguments */
        pgraster = (rt_pgraster *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
        arraysrc = PG_GETARG_ARRAYTYPE_P(1);
        arraydst = PG_GETARG_ARRAYTYPE_P(2);
        bandnum = PG_GETARG_INT32(3); /* One-based band number */
        pixeltype = PG_GETARG_TEXT_P(4);
        if (!PG_ARGISNULL(5)) {
                hasnodata = true;
                nodataval = PG_GETARG_FLOAT8(5);
        }
 
        /* Check arrays have same size */
        szsrc = ArrayGetNItems(ARR_NDIM(arraysrc), ARR_DIMS(arraysrc));
        szdst = ArrayGetNItems(ARR_NDIM(arraydst), ARR_DIMS(arraydst));
        if (szsrc !=  szdst)
                elog(ERROR, "array lengths must be the same");
 
        /* Read the raster */
        raster = rt_raster_deserialize(pgraster, FALSE);
        if (!raster) {
                PG_FREE_IF_COPY(pgraster, 0);
                elog(ERROR, "%s: Could not deserialize raster", __func__);
        }
 
        /* Check that this raster has bands we can work with */
        numbands = rt_raster_get_num_bands(raster);
        if (numbands < 1)
                elog(ERROR, "Raster has no bands");
        if (bandnum < 1 || bandnum > numbands)
                elog(ERROR, "Invalid band index %d, input raster has %d bands. Band indexes are one-based.",
                     bandnum, numbands);
 
        /* Read the band */
        band = rt_raster_get_band(raster, bandnum-1);
        if (!band)
                elog(ERROR, "Could not find raster band of index %d", bandnum);
 
        /* Get array element types */
        pixtypsrc = rt_band_get_pixtype(band);
        pixtypdst = rt_pixtype_index_from_name(text_to_cstring(pixeltype));
 
        if (pixtypdst == PT_END)
                elog(ERROR, "Unknown output pixel type '%s'", text_to_cstring(pixeltype));
 
        /* Error out on unreadable pixeltype */
        if (pixtypsrc == PT_END)
                elog(ERROR, "Unsupported pixtype");
 
        /* Create the rt_reclassmap */
        reclassmap = palloc(sizeof(struct rt_reclassmap_t));
        reclassmap->count = 0;
        reclassmap->srctype = pixtypsrc;
        reclassmap->dsttype = pixtypdst;
        reclassmap->pairs = palloc(sizeof(struct rt_classpair_t) * szdst);
 
        if (!hasnodata)
                nodataval = rt_pixtype_get_min_value(pixtypdst);
 
        /* Build up rt_reclassmap.pairs from arrays */
        itersrc = array_create_iterator(arraysrc, 0, NULL);
        iterdst = array_create_iterator(arraydst, 0, NULL);
        while(array_iterate(itersrc, &dsrc, &nullsrc) &&
              array_iterate(iterdst, &ddst, &nulldst))
        {
                double valsrc = nullsrc ? nodataval : (double)DatumGetFloat8(dsrc);
                double valdst = nulldst ? nodataval : (double)DatumGetFloat8(ddst);
                Assert(szdst > reclassmap->count);
                reclassmap->pairs[reclassmap->count].src = valsrc;
                reclassmap->pairs[reclassmap->count].dst = valdst;
                reclassmap->count++;
        }
        array_free_iterator(itersrc);
        array_free_iterator(iterdst);
 
        /* Carry out reclassification */
        newband = rt_band_reclass_exact(band, reclassmap, hasnodata, nodataval);
        /* Clean up finished map */
        pfree(reclassmap->pairs);
        pfree(reclassmap);
        if (!newband)
                elog(ERROR, "Band reclassification failed");
 
        /* replace old band with new band */
        if (rt_raster_replace_band(raster, newband, bandnum-1) == NULL) {
                rt_band_destroy(newband);
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 0);
                elog(ERROR, "Could not replace raster band of index %d with reclassified band", bandnum);
        }
 
        pgrtn = rt_raster_serialize(raster);
        rt_raster_destroy(raster);
        PG_FREE_IF_COPY(pgraster, 0);
        if (!pgrtn)
                PG_RETURN_NULL();
 
        SET_VARSIZE(pgrtn, pgrtn->size);
        PG_RETURN_POINTER(pgrtn);
}

References rt_reclassmap_t::count, rt_classpair_t::dst, rt_reclassmap_t::dsttype, FALSE, rt_reclassmap_t::pairs, PT_END, rt_band_destroy(), rt_band_get_pixtype(), rt_band_reclass_exact(), rt_pixtype_get_min_value(), rt_pixtype_index_from_name(), rt_raster_deserialize(), rt_raster_destroy(), rt_raster_get_band(), rt_raster_get_num_bands(), rt_raster_replace_band(), rt_raster_serialize(), rt_raster_serialized_t::size, rt_classpair_t::src, and rt_reclassmap_t::srctype.

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