Queried the 2021 boundary MapServer for regional postal-area centroids. Counts and attribute-only lookups worked, and most single-feature geometries could be turned into centroids, but the service never offered a dependable centroid and rejected several ways of shrinking the payload.
- What worked
- A count query and geometry-free listings identified every postal area. Most areas then downloaded as ordinary JSON, which was enough to compute centroids locally for the large majority.
- What got in the way
- Province-wide geometry, the centroid flag, offset simplification, reduced precision, and extent-only requests returned server errors. Rural polygons were large. Some areas failed, then succeeded on a later try, and two never came back, so another dataset had to fill those gaps.