What problem does it solve? Running the HexWatershed C++ watershed delineation model correctly requires deep operational knowledge: mesh JSON must match the configured mesh type, coordinates must be geographic degrees, DEM elevations must be meters, and silent failure modes (skipped outlets, ignored flowlines, unit mismatches) produce plausible-looking but wrong results. This Skill packages that expertise so an agent can build, configure, execute, and validate HexWatershed runs without falling into its documented traps. ## Core Features & Use Cases - Six-stage delineation pipeline: configuration, mesh generation via PyFlowline, flowline preparation, binary execution, output parsing to CSV/GeoJSON, and validation against reference data. - Four executable tools: mesh_converter.py, flowline_converter.py, run_hexwatershed.py, and output_parser.py, plus a preflight_check.py that verifies the binary, Python environment, and required files before any run. - 18 diagnostic triplets: a symptom-to-diagnosis-to-remedy table covering silent unit traps (feet vs meters DEM, km² vs m² cell area, ratio vs absolute accumulation thresholds) and fatal errors (projected CRS, mesh-type mismatch, nodata mismatch). - Use Case: Delineate a watershed on a hexagonal mesh from a MERIT DEM: generate the mesh with PyFlowline, build the config JSON, run the hexwatershed binary, and parse watershed_NNNNN.json into CSV with drainage area, stream order, and drainage density. ## Quick Start Run python preflight_check.py in this directory, then ask the agent to delineate a watershed from your DEM by generating a hexagon mesh with PyFlowline and executing the HexWatershed binary with a validated config JSON.
