# How slopes are computed in Global Mapper ???

edited January 2011
Hello,

Could someone explain how slopes are computed in Global Mapper?
I loaded elevation data (xyz file) and exported the corresponding slopes (File=>Export Raster & Elevation Data=>Export Float/grid file & check the box "Export slope values instead of elevations".
But I haave no idea what the result does represent...
I assume a mean of slopes computed in a given number of directions over a certain distance to each point of interest... it is possible to get more details ?

Patrick

• edited January 2011
Patrick,

The slope is defined as the square root of the sum of squares of the slope along the x axis and the slope along the y axis. Basically if your pixel is at (x,y), Global Mapper calculate the slope from (x-1,y) to (x+1,y) and makes this the x slope, then the slope from (x,y-1) to (x,y+1) and make this the y slope. The slope for the point is then defined as the square root of the sum of the squares of the calculate x slope and y slope.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com
• edited January 2011
Very clear !
Thank you for your fast reaction.

Patrick