HOw to create contours/bathymetry from XYZ point shapefile

Discussion created by RachelB on Apr 29, 2010
Latest reply on Apr 30, 2010 by djain-esristaff
I have a shapefile that contains XYZ data for a lake. Can someone take me through the steps to create contours and then a raster of the area showing the increasing depth.
I'm confused whether to create DEM, ASCII or grid.
All the info for a contours seem to be creating them from DEM which I don't have.
I have spatial analyst and 3D analyst and ArcGIS 9.3.1.

Many thanks