Global elevation migration
unmap is preparing global relief and elevation from a pinned Mapterhorn planet archive. /coverage.json reports the release this deployment serves. The Canadian source remains active until the copy, runtime, performance and rendered-map gates pass.
Response compatibility
GET /elevation, coordinate order, metre units, tenth-metre rounding, authentication, billing
and batch limits remain the same. elevation.get() keeps returning (number | null)[].
Direct HTTP clients must accept both source contracts before activation:
| Field | Canadian MRDEM / rollback | Global Mapterhorn |
|---|---|---|
datum | "CGVD2013" | "mixed" |
resolution | 30 | null (native source resolution varies) |
model | Absent | "mixed" (terrain and surface models) |
sampling | Absent | z12, 512 px, 0.5 m height increment, bilinear |
meta.source | NRCan MRDEM-30 | Mapterhorn and underlying suppliers |
Do not label global values as CGVD2013 or bare-ground height. Encoding quantization is not
measurement accuracy, and an archive publication/copy date is not the acquisition date of every
contributing survey. Negative values and zero remain valid; zero in the ocean may be fill.
Missing tile data and coordinates beyond approximately ±85.0511° return null; corruption
returns 502, and an unavailable selected release returns 503 without automatic source fallback.
Relief, contours and routing
After activation, fresh outdoor styles request /terrain/5/{z}/{x}/{y}.webp. The retained
/terrain/4/...png archive serves embedded older styles. Canadian vector contours keep their
own bounds, archive and attribution; routing graphs retain their recorded build provenance.
Global relief and elevation do not extend routing or geocoding coverage.
Keep style attribution enabled and display the elevation response's attribution where you use the values. Attribution preserves the supplier catalogue alongside the Canadian MRDEM and Copernicus notices. See Elevation API for the complete contract.
