PostGIS Raster : Extending PostgreSQL for The Support of ... - CoDE

BEGIN
newraster := arrayRastTemp[1].rast;
width := ST_Width(newraster);
height := ST_Height(newraster);
size := array_upper(arrayRastTemp,1);
-- Determine pixel type of temporal rasters
IF ST_BandPixelType(newraster) = ’32BF’ OR ST_BandPixelType(newraster) = ’64BF’
THEN intType = false;
END IF;
-- Check if all temporal rasters have same dimensions
IF ST_Width(oldRast1) != ST_Width(oldRast2) OR ST_Width(oldRast1) != ST_Width(oldRast2)
THEN
-- If not then the function raises error
RAISE EXCEPTION ’ST_SumRaster: Attempting to sum a band with different width or height
END IF;
FOR cx IN 1..width LOOP
FOR cy IN 1..height LOOP
FOR s IN 1.. size LOOP
value := value + ST_Value(arrayRastTemp[s].rast,cx,cy);
END LOOP;
value = value/size;
-- Cast the result to an appropriate type
IF intType = true
THEN newraster := ST_SetValue(newraster,cx,cy,value::int);
ELSE newraster := ST_SetValue(newraster,cx,cy,value);
END IF;
value := 0;
END LOOP;
END LOOP;
RETURN newraster;
END;
$$
LANGUAGE ’plpgsql’ IMMUTABLE STRICT;
C.2 Temporal Raster Application
Python code for loading layers into QGIS:
def iniLayers(self):
# Retrieve a connection string
connstring=str(conn.getConnString(self,self.connection))
# Retrieve a list of layer IDs
rids=conn.listRIDs(self, connstring, str(self.table))
# Change QGIS cursor to PostgreSQL cursor
QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.WaitCursor))\\
for rid in rids:
# Split table name from schema
connstring = str(conn.getConnString(self,self.connection))
table=str(self.table).split(".")
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