Assigning Bathymetry

Converting a 2dm file to gr3 or between gr3 or 2dm and shapefile

Assigning depths from prioritized DEMs

These tools are used by the preprocessor but also work with functions that can be used generically and consistently with SCHISM.

stacked_dem_fill

Fill node elevations in a .2dm SMS mesh or gr3 file using a prioritized list of DEMs.

usage: stacked_dem_fill [-h] [--elev2depth] [--fill FILL] filename demfile

Positional Arguments

filename: name of 2dm or gr3 file
demfile: file containing list of DEMs. These can be in any form that gdal accepts, which includes ESRI ascii format and GeoTiffs

Named Arguments

--elev2depth

Convert elevation to depth by flipping sign. This is typical when using gr3 format, less so with 2dm.

Default: False

--fill

Fill value for areas not covered by supplied rasters.

Default: 2.0

Smoother for complex topography

Often it is necessary to incorporate inudated marshy areas where elevations are poorly sampled and contours are tortuous. The script contour_smooth.py uses minmax curvature flow (Malladi and Sethian) to impose a minimum length scale of change for contours, essentially unraveling the features that are most contorted.

Optimizing depths for volume

A mesh draped over noisy bathymetry data does not necessarily represent important moments such as volumes and vertical face areas smoothly and realistically. To better represent these facets of the geometry, we compare the volumetric quantities that come from SCHISM shape functions (which are much like a TIN) to a higher order quadrature using the DEM with bilinear interpolation. The quadrature is more accurate, and also incorporates more sample points.

Perform grid optimization with a *.2dm SMS mesh or gr3 file. An optimized gr3 file with extension _opt.gr3 will be created if only one set of optimization parameter specified.

usage: grid_opt [-h] [--optfile OPTFILE] [--solver SOLVER]
                filename demfile optparm

Positional Arguments

filename: name of 2dm or gr3 file
demfile: file containing list of DEMs. These can be in any form that gdal accepts, which includes ESRI ascii format and GeoTiffs
optparm: file containing optimization parameters: damp, damp_shoreline, face_coeff, volume_coeff

Named Arguments

--optfile

name for the gr3 file for the optimized results

--solver

solver used for optimization, either L-BFGS-B (default) or lsqr

Default: “L-BFGS-B”