The vertical distance or the difference in the elevation between the two contour lines in a topographical map.
Three main differences between contour interval and horizontal equivalent as follows:
|Contour Interval||Horizontal Equivalent|
|It is based on vertical levels||Represents horizontal distance|
|No measurement or scaling is required since the contour levels are indicated on the contour lines||The distance must be measured on the map and converted to actual distance by multiplying with the scale of the map|
|In a given map the contour interval is a constant||The horizontal equivalent varies with slope. Closer distance indicates steep slope and wider distance gentle slope|