Water Areas / Water Lines

Waterways, like Land Cover and Land Use, enrich a digital map display by providing context. A Water Element can be:

A Line Feature representing the centerline of a water course;
An Area Feature representing water.

A Water Course or Area Feature does not necessarily have a clear object extent and a definite boundary. A Water Course or Area Feature may be intermittently dry-like a river that is dry during part of the year-or may be covered with ice. In the digital map, therefore, the boundary may be arbitrary.

Water Areas

The Water Areas file represents the geometery associated with water area features and includes relative area and perimeter attribution.

Note: Swimming pools, marshes, swamps and glaciers are not considered Water Elements.

See also Water Display Class in this user guide for a description of water display classes.

Water Lines

Water Lines represent only linear water bodies (rivers, canals). A Water Center Line represents the main river arm. Minor river arms are not taken into account. When it is not clear which arm is the main river arm, the Water Center Line is then captured for both arms. A waterway's width, or the shipping lane and other factors will determine which is the main arm. Within river deltas or river mouths, the main arm generally corresponds with the shipping lane.

Figure: Water Center Lines

See also Water Display Class in this user guide for a description of water display classes.