Figure 2 An example of combining layers within the Water theme. A. A section of the area showing a raster model of two drainage ditches (width < 1 m) draining into a stream (width < 1 m), with one of the ditches connecting a small lake with the stream. (B), (C), and (D) show a zoom-in on the area where the drainage ditch connects to the lake, with vector layers in (B) and (C) shown for reference. Within each theme, individual layers are processed separately. Here, (B) shows a raster layer of lakes created from a polygon vector layer (shown with a dashed signature). Each lake was surrounded by a 1 m buffer of riparian vegetation as part of the data processing, as detailed riparian vegetation data were not available for this area. (C) shows the drainage ditch raster layer created from a line vector layer (black line). This particular drainage ditch object is < 1 m wide, so after conversion to raster, it is represented by a collection of individual pixels (at 1 m resolution) forming a line. (D) shows how individual raster layers from (B) and (C) are overlaid within the water theme. As objects from the lake layer have the highest three-digit code (code = 143), the lake overlays the drainage ditch (code = 111) at the connection point. Because the drainage ditch layer objects have a higher three-digit code (code = 111) than the lake buffer layer objects (code = 110), the drainage ditch overlays the riparian vegetation at the connection point.