#context("multi-custom")



#multi level features as custom types

# state and county sharing vertices, note rules on internal rings (discard them, leave one level for simple features)
# pre-computed topologically sound resolutions (i.e. district precision for a state boundary vs. country precision)
# a voyage track, intervals within it, fine-resolution underway measures, specific stations
# a fused surface, a combination of contour lines with a constant Z fused with polygons without elevation

