Technical data

Building Surfaces

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Watershed subareas can have different types of drain targets. Drain

targets of some subareas can be based on a boundary point, the point

where the channel of water would drain off the surface. Drain targets

of other subareas can be depression areas where the water will flow.

Key Concepts

■

If the Watershed command determines that water from one TIN

surface triangle could flow into more than one watershed subarea,

then it splits the TIN triangle to make two triangles. This ensures

that each watershed consists of complete triangles, and that the

boundary of each watershed consists solely of TIN edges.

■

If you use contour data to build the surface, then be sure to use the

Minimize flat triangles resulting from contour data option in the

Build Surface dialog box to minimize the number of flat triangles

that make up the TIN surface, and thus make the watershed model

more accurate.

To build a watershed model

Steps

Use

to look up

From the Terrain menu, choose Terrain Model

Explorer to display the Terrain Model Explorer

dialog box.

Create and build a surface model if one does not

exist.

Build a Surface

Open the surface folder to display the data tree.

Right-click the Watershed icon and choose

Calculate Watershed.

Overview of Creating

Watershed Models