How can I be able to generate the slope of a raster file (dem). I need here two types of slopes: the slope in the x-direction, and the slope in the y-direction of the same dem raster file.
Seems to me the best approach would be calculate aspect and slope, and then build a map algebra expression (using basic sin/cos trigonometry) to separate the slope in to X and Y components using the aspect.
I would be very careful as to which coordinate system you use so the X and Y will "make sense" (for example so "north" will be "up").