Using ArcGIS Pro Spatial Analyst to create Slope & Aspect Rasters

hi there in this video i'm just going to very quickly talk about slope and aspect uh there's some tools in both 3d analysis and spatialist which make it all very easy and generate rasters for you and from there you can go on to do other analysis such as correlating those rasters with vectors and that sort of thing and i will be doing that in a in another video so here we have um this is the esri hybrid imagery layer i've actually turned off imagery at the moment but there it is so around the sort of austria area as you can see um let's turn that off for a moment so that's where we are in the world uh this is srtm the tiff file or one of them the shuttle uh data so what i'd like to know is sort of what sort of steep areas you know just just highlight those steep areas for me well in the analysis go to tools um you can we're working on slope so type slope and as you can see it's come up with 3d analysis and spatial analysis yes there are others and we can i'll probably talk about those another time but we primarily want to get okay what's the steepness show me the areas of steamness so um doesn't matter which one i click input raster is your main this is the main sltm on its input then the output is it's automatically numbered that i've done this a few times um the output measurement degree of percentage rise so degree by default percentage rise so that's the idea of um so the degrees will be north to 19 centers rise will be flat surfaces is not percent and 45 degree will be 100 and then you you go up from there as you as you get steeper uh i just leave it as planar um in terms of rather than geodesic um for greater accuracy you really ought to you know it will take meters by default but but you need to sort of make sure you know what data you've got and therefore what z factor will be applied um so probably give me a warning but i'm not not too bothered about that i just want to show the steepness okay so here you can see it's created my uh slope um let's turn off the sltm underneath um it's created my slope raster uh as expected it's got a warning and it will be about the yeah the the um units not properly defined um but but but that's okay for this for this these purposes i'm only working in this in this single sort of tile in this single extent so uh i just want to know what the steepest areas are inside this so you can see as i zoom in here you get um dark color classification darks and symbology for the steeper areas and lighter for the um flat or not so steep so that makes sense that looks good uh so so there you go that that is your slope calculation but what about the direction of the slope what i'd like to do is um is actually create an aspect raster dataset on top of this so i can see which direction the slopes are pointing and so in the tools aspect search click on aspect the input raster is the srtm so that's the main srtm and we will uh just again just go with plain art and run it so it is now finished and it will draw there you go a very garish aspect raster very garish indeed there's default classifications there that it's just different colours symbology and um let's assume in a bit so you can see that uh from let's say the this sort of light the cyan this light bluish color um it's very south so that's what you can see that that's all the southern facing stuff so you might be looking at some kind of solar implementations technology implementation or something um but you know there's lots of reasons why you may want to know this but but also because it's just a straightforward symbology classification you can you can do whatever you like to all of these colors etc you don't have to go with um there there you go so but you'd be better off really trying to create a lot of individuality you know to to those colors because because then they they stand out a lot better so ie you know something like uh basic random or something so you see you get a much much greater difference in in colors and in there you can see exactly what you're getting and then you can correlate all the other data on top what i might do actually is turn some of these off i could do some raster calculated stuff here as well actually so let's say i'm only fussed about southeast for whatever reason and i'll just very quickly turn these off um and yeah i'll turn that one off as well i think so i just left the south east there you go so now we've got just southeast facing slopes um in in that area and underneath we can see the darker steepness value there as well so as you can see we could then go off and do all sorts of analysis and in fact in my in in my uh next video that's coming up shortly i'm going to be doing a bit bit bit more analysis using this exact data and sort of extracting data onto vectors and things like that gradients of road networks so anyway i hope you found that useful dead easy for slope and aspect calculations just type them in geoprocessing under analysis tools do your processing find them run them only a few settings needed and then off you go i hope you find that useful thank you

Channel: GIS Coordinated

Views: 8,965

Keywords: GIS, maps, esri, arcmap, arcgis, raster, slope, aspect, direction, angle, srtm, shuttle, raster data, degrees, planar

Id: DoA5p49OIrs

Length: 6min 42sec (402 seconds)

Published: Sun May 16 2021