topic slope analysis in ArcGIS Spatial Analyst Questions https://community.esri.com/t5/arcgis-spatial-analyst-questions/slope-analysis/m-p/447905#M6343 <HTML><HEAD></HEAD><BODY><SPAN>When I use the Spatial Analyst extension to complete a slope analysis on a DEM the classification doesn't make any sense.&nbsp; The following is the classification when using the percent option: </SPAN><BR /><SPAN>0-119706.2706</SPAN><BR /><SPAN>119706.2727-217647.767 </SPAN><BR /><SPAN>and these number continue past 2,000,000.</SPAN><BR /><BR /><SPAN>When I use the Degree option the image appears a solid color and it won't let me classify more then 1 class which is 0-90...</SPAN><BR /><BR /><SPAN>In addition, I have been able to successfully use the aspect tool.&nbsp; However I can't figure out how to analyze a group of GPS point on top of the raster.&nbsp; I am trying to figure out which aspect the points are usually on.</SPAN></BODY></HTML> Mon, 15 Nov 2010 19:50:31 GMT PaulHood 2010-11-15T19:50:31Z slope analysis https://community.esri.com/t5/arcgis-spatial-analyst-questions/slope-analysis/m-p/447905#M6343 <HTML><HEAD></HEAD><BODY><SPAN>When I use the Spatial Analyst extension to complete a slope analysis on a DEM the classification doesn't make any sense.&nbsp; The following is the classification when using the percent option: </SPAN><BR /><SPAN>0-119706.2706</SPAN><BR /><SPAN>119706.2727-217647.767 </SPAN><BR /><SPAN>and these number continue past 2,000,000.</SPAN><BR /><BR /><SPAN>When I use the Degree option the image appears a solid color and it won't let me classify more then 1 class which is 0-90...</SPAN><BR /><BR /><SPAN>In addition, I have been able to successfully use the aspect tool.&nbsp; However I can't figure out how to analyze a group of GPS point on top of the raster.&nbsp; I am trying to figure out which aspect the points are usually on.</SPAN></BODY></HTML> Mon, 15 Nov 2010 19:50:31 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/slope-analysis/m-p/447905#M6343 PaulHood 2010-11-15T19:50:31Z Re: slope analysis https://community.esri.com/t5/arcgis-spatial-analyst-questions/slope-analysis/m-p/447906#M6344 <HTML><HEAD></HEAD><BODY><SPAN>ensure that your data are projected (not projected on the fly) and that the X, Y and Z values are in the same units (ie meters, feet or the z-factor is accounted for using an appropriate scaling factor).&nbsp; These issues are discussed in the help files should you require further information.</SPAN></BODY></HTML> Mon, 15 Nov 2010 19:59:47 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/slope-analysis/m-p/447906#M6344 DanPatterson_Retired 2010-11-15T19:59:47Z