hi I need compute Aspect without using Aspect Tool in ArcMap i use algorithm which is in help.. http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=How%20Aspect%20works but question is how can i compute aspect at the edge of the raster where is impossible create matrix 3x3? (or if there is some noData in matrix) At the bottom of help there is example how to compute aspect for center cell in matrix 3 x 3. but i dont´t understand how algorithm works for others cells.. do you have any idea?? thanks a lot.
