int
G3d_readRange(const char *name, const char *mapset, struct FPRange *drange)
/* adapted from G_read_fp_range */
{
int fd;
char xname[GNAME_MAX], xmapset[GMAPSET_MAX];
char buf[GNAME_MAX + sizeof(G3D_DIRECTORY) + 2],
buf2[GMAPSET_MAX + sizeof(G3D_RANGE_ELEMENT) + 2];
char xdr_buf[100];
DCELL dcell1, dcell2;
XDR xdr_str;
G_init_fp_range(drange);
fd = -1;
if (G__name_is_fully_qualified(name, xname, xmapset)) {
sprintf(buf, "%s/%s", G3D_DIRECTORY, xname);
sprintf(buf2, "%s@%s", G3D_RANGE_ELEMENT, xmapset); /* == range@mapset */
}
else {
sprintf(buf, "%s/%s", G3D_DIRECTORY, name);
sprintf(buf2, "%s", G3D_RANGE_ELEMENT);
}
if (G_find_file2(buf, buf2, mapset)) {
fd = G_open_old(buf, buf2, mapset);
if (fd < 0)
goto error;
if (read(fd, xdr_buf, 2 * G3D_XDR_DOUBLE_LENGTH) !=
2 * G3D_XDR_DOUBLE_LENGTH)
return 2;
xdrmem_create(&xdr_str, xdr_buf, (u_int) G3D_XDR_DOUBLE_LENGTH * 2,
XDR_DECODE);
/* if the f_range file exists, but empty */
if (!xdr_double(&xdr_str, &dcell1) || !xdr_double(&xdr_str, &dcell2))
goto error;
G_update_fp_range(dcell1, drange);
G_update_fp_range(dcell2, drange);
close(fd);
return 1;
}
error:
if (fd > 0)
close(fd);
G_warning("can't read range file for [%s in %s]", name, mapset);
return -1;
}
int QgsGrassGisLib::G_read_fp_range( const char *name, const char *mapset, struct FPRange *drange )
{
Q_UNUSED( mapset );
Raster rast = raster( name );
// TODO (no solution): Problem: GRASS has precise min/max values available,
// in QGIS we can calculate, but it would be slow, so we are using estimated
// values, which may result in wrong output
// Hopefully the range is not crutial for most modules, but it is problem certanly
// for r.rescale .. more?
// TODO: estimate only for large rasters
warning( "The module needs input raster values range, estimated values used." );
int sampleSize = 250000;
QgsRasterBandStats stats = rast.provider->bandStatistics( rast.band, QgsRasterBandStats::Min | QgsRasterBandStats::Max, rast.provider->extent(), sampleSize );
G_init_fp_range( drange );
// Attention: r.stats prints wrong results if range is wrong
G_update_fp_range( stats.minimumValue, drange );
G_update_fp_range( stats.maximumValue, drange );
return 1;
}
