I am trying to analyse the terrain using slope, aspect, contour, relief to work on interventions for streams. Therefore. I am interested to learn about the curvature feature and how it can help me in this analysis.
If we consider that your elevation is your main dataset, then the slope, can be considered the first derivative, that is the change of elevation over a distance. Similarly, curvature can be the second derivative of elevation or, the change of slope (the first derivative) over a distance.
-A profile convex curvature (a negative value) means that your DEM is upwardly convex, slope is diminishing, like a dome.
-A profile that is concave (a positive value) is upwardly convex, slope is increasing, like a bowl.
-A curvature of zero means a straight line, the slope is not changing, like a plane.
The curvature of a terrain may bring some light about hydro-logic and hydraulic phenomenons, like acceleration and deceleration of flow, as well as erosion and accretion (deposition).
You can learn more about the tool at: http://desktop.arcgis.com/en/arcmap/10.3/manage-data/raster-and-images/curvature-function.htm
Best.
Miguel.
dear Atri,
I agree with Miguel's reply.
As for the meaning in hydrology and river dynamics, I may add that the analysis of slope curvature can shed light also on the soil saturation potential and may provide insights into the relative probability of soil water relationship in a given area. In short, profile curvature, suitably averaged in space, should rely information on river profile changes (such as nickpoints and counterslopes) and on valley longitudinal profile as well. For example, when valley profile curv is discontinuous with respect to the river course, it may mean that some hillslope processes (such as mass movements) are interfering with fluvial processes in the valley bottom.
Plan curv, instead, may reveal important trends in water divergence or convergence and highlight zones of potential soil saturation. For example, areas with the highest values are candidates for saturation overland flow to take place (provided that you have a sufficient soil cover and rain, of course). A powerful derivation of such measures is given by the Topographic Wetness Index TWI=log(contributing area/slope).
You may want to refer to some of recent research which demonstrate that such metrics are good proxies for water and sediment transport on slopes in ungauged basins. Please have a look at my ReseachGate open access publications and references therein.
Hope this may help.
ciao
Filippo