Extracting Elevation Data from Google Earth

hello guys welcome to another tutorial in this tutorial i'm going to show you how to extract the elevation data from google earth in a very straightforward manner now i hope you guys have installed this google earth pro application already and to demonstrate this to you guys i'm actually using some area in malaysia so what i'm going to do is i'm going to zoom into that area of interest and before you do anything let's see that when you hover your mouse over just draw your attention to the lower right corner of your screen over here you can see that under the elevation value the value actually does not change it's just a fixed value at zero meters so that's the first thing actually we need to fix we need to go over here and turn on this terrain option and once you turn that on and when you just hover your mouse over like this you will see that now the elevation value actually changes accordingly so let's say for example when you take your mouse somewhere over here to the mountain tops you will see that the elevation actually changes to be a higher value but when i put my mouse somewhere maybe in the lower lands like this you can see that the elevation value changes correspondingly right now you can just kind of get an idea that there's kind of a hidden set of elevation values in google earth itself and how to extract that into maybe a gis software so that we can develop our own dem or maybe develop our own set of contours that's exactly what i'm going to explain to you guys today so first of all let's go over here and select on this add path tool and after that you can actually just give a name of your choice and before you click ok what you need to do is now you need to create as many points as possible just by drawing the path like this now you can see that the slower you move your mouse cursor it actually draws the path by creating a series of points now if you try to drag your mouse a bit faster you can see that the interval between the points become actually larger but in order to do this exercise quite accurately it's quite important that actually you draw this path a bit slower so that the number of points actually will be higher all right once you have done this maybe i'm just going to go a couple of strokes like this as well now to explain to you guys what we are trying to do over here is basically we are trying to extract the elevation value of each of these points that you see over here now you can see that once we get that into a some sort of a table it's going to be actually quite a number of points and the more points you have the more accurate your dem or the more accurate your contours are going to be all right i think for the demonstration purposes this should be sufficient or let me just conclude this by making another stroke over here actually you can just go crazy like this i mean there's no particular way of doing this all you need to do is just to cover as many points as possible something like this just trying to actually fill in the gaps which i left while drawing those strokes yeah i think this should be sufficient all right now once you have done that you can click ok to confirm this and you can see that now we have a path called elevation points what i'm going to do is i'm going to right click over here and select save place as and after that i'm going to save that file as not as a kmz but as a kml keyhole markup language dot kml file format all right once you have done that you can simply hit save all right next what i'm going to do is i'm going to open up this website called gps visualizer dot com slash elevation i'll put this link down in the description as well so that you don't have to spend time typing out this one you can simply click on that link and you can go to this gps visualizer slash elevation and from here i'm going to upload a file so i can simply select choose file and the file that i'm going to choose is the kml file which i just saved into this folder all right after that just make sure that your output is actually a gpx file and now what i'm going to do is i'm going to convert this kml file into a gpx file just by clicking on this convert and add elevation button now it will take a couple of seconds and after that it will actually generate this output for you and you will have this dot gpx file right here now you can simply click on that and it will download the file for you guys just like this well after that you can actually move that file into into your folder into any fault of your interest as well all right so this is the corresponding gpx file which actually corresponds to these elevation points all right now what i'm going to do is i'm going to go ahead and open arcgis all right once you open arcmap just go to the search tool and from here just type gpx what we are trying to do now is we are trying to convert that gpx file into features using this gpx to features conversion tool which is actually quite handy that it has already been built into arcgis now the input gpx file all i have to do is navigate to the place where i have saved that file just like this and you will see that it will automatically detect this gpx file and after that you can open that and correspondingly you can also specify the location to which you would like to generate your output feature class now when you specify the location you can see that automatically the corresponding file format turns out to be dot shp which means now it's going to create some sort of a shape file but still we are not so sure what's what sort of a share file it's going to be so let's go ahead and click ok and see what kind of a shape file actually generates for us all right now you can see that quite clearly we managed to extract this path into a shapefile like this but not really in terms of the lines but in terms of some points all right now let's go ahead and do some exploration on these points first of all i'm just going to open up the attributes table and see actually what we have over here all right now you can see that each point has been specified as a single attribute and over here we have the most important information which we need which is basically the elevation value in terms of uh meters all right that's quite good and the next thing that i'm going to be interested is to see whether this has already been geo-referenced or not so i'm just going to go to properties and from here when i check the coordinate system you can see that it's actually already geo-referenced as well it's in wgs 1984 geographic coordinate system so actually i don't have any issues right now and i can directly proceed to create the dem using these points so actually most of our work is done by now what we can do is we can simply go over here and select some sort of an interpolation method now what basically interpolating is we are trying to predict the elevation value of these areas where we do not have points based on the elevation of the points nearby now there are different interpolating methods like the idw or krigging now for this exercise i'm actually going to go with cricking interpolation method all right i'm just going to go ahead and select this qriking spatial analyst tool and now my input is going to be this elevation points and i'm going to interpolate based on not the id value but based on this elevation value if you can recall the attributes table the elevation values were recorded under this elevation column so the heading of that column is elevation so that's what i'm going to select over here as a z value and the output cell size now since we are working in geographic coordinate system the unit is actually in decimal degrees so the cell size that you have to enter over here is b is actually not going to be in meters for example if you would like to have a cell size of 10 meters you have to enter the corresponding dimension of the cell in decimal degrees so for this exercise i'm actually i'm just going to retain this cell size like this and even the other options i'm going to actually retain it like this and after that i'm just going to select ok yeah now you can see that we managed to generate some sort of dem like this now if you would like to play around with the cell size maybe what i can do is i can again drag this and select elevation over here and if you would like to have maybe a lower cell size i can add another zero over here and let's see whether we get quite a big difference in terms of the the result compared what we have right now and now since we specified a final cell size you can see that takes a bit more time for the interpolation to take place all right now you can see that actually the difference is only very subtle i'm just going to pick one from this maybe i'll just go with the first one so this is basically your interpolated dem well you can see that the color distribution is like this now if you would like to change the colors distribution you can always go to properties and go to symbology and from here maybe you can increase the number of classes to let's say about 15 and select a different set of color distributions and if you would like to revert the color the color ramp you can flip the colors like this so that the lower elevations will be specified in blue color and high elevations will be specified by by the red colors yeah something like this so you can very clearly see that these are basically going to be the lower areas and these are the high areas and of course what you can do is you can also create generate the contours you can go to this contour spatial analyst like this and as the input raster you can basically input this kriging raster which you just created and from here you can specify the contour intervals now by looking at this distribution of the elevation values maybe i can just come up with some sort of a contour interval let's say i would like to specify this with intervals of 20 meters and after that i can click ok i think that maybe i can increase the interval a bit let's say maybe about 90 meters just like this so that the density of the contours will not be as high as this previous one and now if you would like to maybe change the line color you can change it like this and if i open this attributes table you can see that the contour value has been specified in this column which i also can actually transfer into this map i can simply go to properties and go to labels and from here i can tick on this label features in this layer and i'm going to select the column contour and when i hit apply you can see that the corresponding contour values also appear over here obviously you can do the amendments to the to the text from here yeah just like this all right now if i zoom in you can see that i can very clearly see the contour values as well over here it's about yeah 1980 meters above the mean sea level whereas these areas correspond to elevations like let's say 550 over here and this dark blue area should be much lower as well yeah about 180 over here all right so i guess that's about it for this tutorial now you can see that very clearly we were able to extract the corresponding elevations of this particular area and transfer those information from google earth into our gis software like arcgis and generate our own dm and contours just like this so i guess you learned something new and if you did like this tutorial do not forget to show your support by liking this tutorial and also if you would like to see more interesting tutorials like this you can definitely subscribe to this channel as well so until i see you guys in the next tutorial take care and have a good day

Channel: GeoDelta Labs

Views: 54,853

Rating: 4.9642568 out of 5

Keywords: Extracting Elevation Data from Google Earth, contour line, contour lines, contour line google earth, dem google earth, Contours from Google Earth, DEM from Google Earth, TCX Converter, Remote Sensing, GIS, Geoinformatics (Field Of Study), Spot Heights from Google Earth, Digital Elevation Model, Google Earth, ArcMap, ArcGIS, ESRI, Interpolation, DEM, Kriging, IDW, natural neighbour interpolation, contour, DEM elevations from Google Earth

Id: isDop9WKdjk

Length: 13min 24sec (804 seconds)

Published: Thu Sep 10 2020