Checking and enforcing dowstream Z constraint for synthetic streams

RicardoLopez-Torrijos1 — Fri, 02 Feb 2018 15:46:04 GMT

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data (about 1 ground point per square meter or greater). To convert them into 3D breaklines I use a conflation process (InterpolateShape) to populate the Z from the same lidar. Before using them for hydro enforcement in DEM derivation, one needs to see that the vertex elevations decrease monotonically in the downstream direction -due to ground vegetation noise and/or leftover structures in the lidar this is not always the case. Does anybody know of a tool/code to:

Check for downstream elevation monotonic decrease? The tool would detect and tag (by feature ID and measure?), polyline segments where the stream deviates from strict downstream gradient. An illustration:

Enforce the downstream Z monotonicity when errors are found? After enforcement the stream above would look something like:

It seems the functionality exists in the Defense Mapping + Production Mapping extensions (see http://desktop.arcgis.com/en/arcmap/latest/extensions/defense-mapping/correcting-monotonicity-errors.htm), but these are of restricted distribution.

Thanks!

Re: Checking and enforcing dowstream Z constraint for synthetic streams

RicardoLopez-Torrijos1 — Tue, 01 May 2018 15:28:45 GMT

The functionality I describe exist in... Arc Hydro! There are actually two tools, Toolbox > Arc Hydro Tools > Watershed Processing > Smooth 3D Line: "Smooths 3D lines linearly in the digitized direction."

Another, applies the downstream constraint to a dendritic network, with a check that the constraint is kept at stream junctions. It is Toolbox > Arc Hydro Tools Python > Watershed Processing > Line Processing > Make 3D Line System > Make 3D Line System: "Construct a 3D line from input 2D line by getting the Z value from the input DEM, and M value from the distance between the vertice and vertice[0].'. Activate the Z smoothing parameter to apply the constraint.

Thanks to Dean Djokic for the pointer, and to the AWRA GIS in Water Resources conference for having brought us together.

topic Checking and enforcing dowstream Z constraint for synthetic streams in Water Resources Questions

Checking and enforcing dowstream Z constraint for synthetic streams

Re: Checking and enforcing dowstream Z constraint for synthetic streams