Validation
This chapter compares our output with that of gdaldem.
We test with the same elevation model as that in the Usage page, and also include an upside down version of it, to ensure that the algorithms are robust to different axes conventions.
julia
@info Geomorphometry.cellsize(dem) # default negative y spacing
@info Geomorphometry.cellsize(ndem) # reversed y spacing
┌ Error: Unknown CRS type, please report this issue for the given crs/file
└ @ GeoArrays ~/.julia/packages/GeoArrays/X63Mm/src/geointerface.jl:11
[ Info: (5.0, -5.0)
┌ Error: Unknown CRS type, please report this issue for the given crs/file
└ @ GeoArrays ~/.julia/packages/GeoArrays/X63Mm/src/geointerface.jl:11
[ Info: (5.0, 5.0)
Hillshade
julia
heatmap(hillshade(dem))
Multihillshade
julia
heatmap(multihillshade(dem))
Slope
Horn
julia
heatmap(slope(dem, method=Horn()))
ZevenbergenThorne
julia
heatmap(slope(dem, method=ZevenbergenThorne()))
Aspect
Horn
julia
heatmap(aspect(dem, method=Horn()))
ZevenbergenThorne
julia
heatmap(aspect(dem, method=ZevenbergenThorne()))