I'm using gdaldem to create a slope map.
I can apply a scale. The default is 1.
The notes say:
Ratio of vertical units to horizontal. If horizontal unit of source DEM is degrees (e.g WGS84 projection), use scale=111120 if the vertical units are meters (or scale=370400 if they are in feet)
Can someone explain this to me in layman's terms.
My DEM is in NAD27 UTM 18N and in the projection properties it says linear units Meters and angular units degrees.
How do I know what the vertical units are and what the horizontal units are?