Case Study – Hydro-Flattening

Muskegon County, Michigan

Surfaces of streams, rivers, lakes, and reservoirs are understood to be “flat” from shore to shore. However, due to water surface movement (such as ripples or currents), Lidar data from areas containing hydro features may show noise and other artifacts on or around bodies of water. This causes hydro surfaces to display in an uneven way—appearing to the viewer not to be “flat” and cluttered with artifacts, as shown in Figure 1.

Hydro-flattening applies software processes to generate a breakline for shoreline areas in order to “flatten” a body of water’s surface elevation. This allows for more a accurately displayed appearance for bodies of water in Lidar datsets. Hydro-flattened datasets display enhanced aesthetics and deliver greater accuracy for products such as contours and floodplain studies. Figure 2 illustrates hydro-flattened water bodies (blue breaklines) and hydro-flattened downhill-flowing rivers (purple breaklines).

Figure 1. Sample – Hydro Flattening Not Applied

Figure 2. Sample – Hydro Flattening Applied