6.3.1 Layer Types

Layers used in VO can be grouped to four (4) different types:

1. Hydrologic Object Layers – Layers that are used to store and display hydrologic objects.
2. Support Layers – Layers that provide support functions.
3. Base Map Layers – Layers that provide background map data (Available only in ArcGIS).
4. Imported Layers – Layers added by users.

Both the Hydrologic Object Layers and Support Layers are system layers and are saved in the project file. They can’t be removed from Table of Content.