Resolves an elevation (metres) for a sampled coordinate. May be sync or
async — a decoded raster lookup, a server elevation endpoint, or anything
else. Receives the sample index and cumulative distance for convenience.
Return a non-finite value (e.g. NaN) to mark a coordinate as no-data; it
is treated as 0 in the profile summary.
Resolves an elevation (metres) for a sampled coordinate. May be sync or async — a decoded raster lookup, a server elevation endpoint, or anything else. Receives the sample index and cumulative distance for convenience. Return a non-finite value (e.g.
NaN) to mark a coordinate as no-data; it is treated as0in the profile summary.