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Make the max polygon point count a constant

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And document it in context.
This commit is contained in:
Chris Hill-Scott
2021-07-06 15:33:01 +01:00
parent 2accf8434a
commit a766324559
1 changed files with 7 additions and 1 deletions
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8
app/broadcast_areas/create-broadcast-areas-db.py
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@@ -27,6 +27,12 @@ point_counts = []
invalid_polygons = [] invalid_polygons = []
rtree_index = RTree() rtree_index = RTree()
# The hard limit in the CBCs is 6,000 points per polygon. But we also
# care about optimising how quickjly we can process and display polygons
# so we aim for something lower, i.e. enough to give us a good amount of
# precision relative to the accuracy of a cell broadcast
MAX_NUMBER_OF_POINTS_PER_POLYGON = 250
def simplify_geometry(feature): def simplify_geometry(feature):
if feature["type"] == "Polygon": if feature["type"] == "Polygon":
@@ -125,7 +131,7 @@ def polygons_and_simplified_polygons(feature):
point_counts.append(simplified.point_count) point_counts.append(simplified.point_count)
if simplified.point_count >= 250: if simplified.point_count >= MAX_NUMBER_OF_POINTS_PER_POLYGON:
raise RuntimeError( raise RuntimeError(
'Too many points ' 'Too many points '
'(adjust Polygons.perimeter_to_simplification_ratio or ' '(adjust Polygons.perimeter_to_simplification_ratio or '