How can I calculate 3D surface area base on slope in GIS for each morphological units in watershed?
You will need 3D analyst
Create a TIN using your polygon
- Add Surface Information with your polygon as input feature class and the corresponding TIN as input surface.
- Check "SURFACE_AREA" box as output property.
The 3D area is then added in a new field to your polygon feature class' attribute table.
This post provides the steps Calculating 3d polygons' surface area using ArcGIS for Desktop?