ArcView 3x automatically drive slope through its 3D analyst in degree unit. Some applications need slope value in percent unfortunately. Here is one of tips to convert ESRI Grid froom degree to percent.
- Using ArcView 3x, Drive your slope using 3D analyst (menu Surface > Drive slope)
- Select resultant theme should be on TOC
- Menu Analysis > Map Calculator
- Fill the formula as follow
100.AsGrid * ([slopedegreename] * 3.141592654/180).Sin / ([slopedegreename] * 3.141592654/180).Cos
Change slopedegreename with the name of slope in degree. To execute the formula, Klick on Evaluate. View the tutorial here.