hello and welcome to this tutorial where I'll be teaching you how to download super high resolution elevation data from the 3ep 3D elevation program of the USGS service and um here we can have a quick look at what this data can look like let's build it at full resolution and you can see in this case we have a 0.5 m per pixel resolution and it gives us very very high detailed Fidelity so let me show you so first thing first we're going to go to the National map downloader you can find the link in the description and we're going to select elevation Source data we're going to unclick lier Point cloud and click on digital elevation model Source click on show so that we're going to see where the data is available for download you can see there's different colors if we click on show Legend we can see that magenta is less than 1 m per pixel data and the red one is 1 meter per pixel the magenta one is usually 0.5 m per pixel so it's quite High detail data and from there we're just going to find an interesting area to download what I usually do is change the um base layer of the map to the either image where we can spot some interesting areas I think this one is actually yam park or we can also go for shaded relief also makes it easier to pick out some interesting spots and um yeah I think this is actually Park we can see from here USM National Park so let's try to download some elevation data from that zone there is multiple ways the easiest one is to select extend and just draw a rectangle around the area we want to download from there we go to search products so there you go we have a result and the result basically consists of all these little tiles of f mops which we all need to download and combine for downloading them we're going to download this text file which is composed of 351 links I'm going to open the file and we're going to select and copy all of them now this is going to launch a process instead of J downloader 2 which is a program where which I also Link in the description and basically it's starting to add all the links to their download list okay theyve all been added I'm going to select them all deselect one and drag them all into that one so now we have them all inside of a single folder we're going to start to download and we're going to wait for it to finish so down down is finished we're going to launch Huges and we're also going to copy the directory to where we downloaded our files so cuis is a free geographic software basically used for combining all types of uh of geographic uh material digital material from there we're going to click on rer miscellaneous build vir rer going to select some files from the folder going to select them all and click on run so our rer was complete this is what it looks like and now I'm going to teach you quickly how to import this file into World machine for this we need to export this and get rid of some values for example here in the upper right corner there's some basically transparent values which Q just interprets as no data values for that we need the fill no data cells you can find us if under the processing toolbox which can be found in view toolbars or is it no maybe panels processing toolbox and there Ruster tools for no data cells we're going to select our virtual Ruster and for the FI value we going to pick the lowest value which in this case is 1,131 m 1,131 m that means that the lowest elevation of this whole file here is 1,000 m above sea level the highest one being 2,000 800 and also can be quite useful to note down the dimensions of the file basically here we can see the width is 48,000 and the height 30,000 this is pixels and if we scroll down we find the pixel size to be 0.5 it means 0.5 m per pixel so and we're going to save this file we're going to save it here in my digital elevation model folder I'm going to save [Music] this and I'm going to add the dimensions of this file to the name of the file that's going to make it easier after in word machine so what did we say 48,000 plus the height but we divide it by two because it's 0.5 m per pixel so that me 24 by 15 K and the height of the of the whole terrain goes from 1,31 calculator 2, 838 minus 100 1,131 gives us 17 M of height difference wait how much was it one 1717 M with the height and 0.5 m per pixel Tiff and we click on run the file has stop processing and I've opened up word machine I'm going to select a file input and into that I'm going to drop the file we just processed and you have to be careful to not put in F which are too big because uh word machine is going to hit the memory limit now this file here is taking up 4.5 5.4 gabt of RAM memory I have acquired a lot of ram 64 GB and so can still fit but it happens quite frequently that you download a lot of data and that the final file that you're building is way too big and um one solution for that is here in qis you can zoom into an area and if you only want to export the area which youve zoomed into you can click export save as and map canvas extends then you add your P path on here and you click okay and that's going to export only the area which is inside of the viewfinder here so we can close this and let's take a look at this again actually the dimensions were 24 kilm by 15 km we had a height extent of 1,77 M and the resolution was of 0.5 m per pixel that means on 4 kilomet we can put a resolution way up to 8,000 which is very high resolution I'm going to control space to open up side 3D preview here and on this I'm going to click on the Explorer extend so from here we can move our extent around and we can preview the file that we just downloaded let's actually look at this area here which is probably the most famous one of the yam value you can see this is the file with an actual detail there's a lot of information if you move your light around appear here in the viewfinder on the small viewfinder you can take a clearer look at all the small details for example these small rocks here and voila you want to explore a little bit more you can move your main extent around look at some new areas and that's the most powerful thing about loading these files into World machine I think other problem other programs such as Gia don't have a easy way of browsing your bigger files because usually they're all loaded into the view and yeah I hope you enjoyed this tutorial and you learned something useful
