Very High Resolution DEM and Contour from Google Earth || Q GIS 3.14 || Detailed Hands-on ||

okay so welcome to everyone in my channel the geography lab so after so long time i am going to press i am going to making this video and from now there will be a continuous video anyway today the topic of the tutorial discussion is how to generate high resolution digital elevation model so in general there are several uh digital elevation data that is uh basically these are basically the asa teamed in that is the space satellite topography mission and the aster damn data okay apart from these two data's we have the alloys pulsar terminator so the highest resolution of the dim data is for the alus pulsar dim data it is 12.5 meter and rest of these are belong to 30 or 90 meter dime data okay but in this video we are going to create uh the dim data from the google earth engine or sorry google earth uh pro so our objective is to create a very high resolution name so that we can use uh for micro level uh elevation mapping because for say example if i want to make a microbial digital elevation differences using these data this could not be possible or even possible but the representation could not be successful okay so for this reason uh we have to generate the digital uh elevation model based on our uh primary input or in other words manually we can generate this okay so the google earth pro is a very good uh alternative to generate the digital elevation data and from this google earth pro we can easily incorporate or export it to the qgis interface or other interface so we can produce the digital elevation raster data okay anyway so there are basically three successive stages for developing a day first we have to uh create some kind of a path we should contain three type of dimension first x and y and associated jet that means if we want to create one path and every each and every path should have some kind or some sort of vertexes or the nodes and each nodes is dedicated to uh three type of information that is the latitude longitude as well as the elevation that is the x y z so in order to create the path ah okay so this is my one kind of case studies area because i am choosing this studies area because it is a ah it is the area where we have a great uh you know voltage regular differences so we can easily visualize our result okay anyway so for creating the part we have to go to this button that is the add path button so after clicking that path button you just keep it aside and just draw irregular path okay so it is keep in mind this there is no such kind of rule of thumb to generating the path but one main thing is that you have to maintain uh the entire area equally that means the distribution of the random path should be equally distributed over the pace for example if i want to ah create this kind of area for single with this uh square save area so my distribution of the paths would be equally spreaded in between this region okay so in this way we have we can generate or we can fill this zone using as much as uh nodes or vertex using the add path option anyway for showing the you know this tutorial i am just covering i just draw the uh this amount of the path with this amount of uh nodes okay anyway i'm giving this name is simply name kml and okay so my path is save here now keep in mind it's this we have to save uh this file as kml file okay it is very important not kmj we have to save it as kml file so now just create one folder in desktop that is a name and our file is safe there okay anyway so then our first step is done actually so we have successfully created the digital device that the path for creating the detail innovation model now our second step is to go to this specific website that is the gps visualizer dot com slash elevation so here we have to generate the date name database because through this path we have x and y values corresponding to these nodes or vertexes but we did not able to capture the z dimension that is the elevation dimension so for that we have to assign the elevation data corresponding to this nodes so for that we need we need to uh take this help from the gps visualizer anyway so from here you have to upload the file and just go to the specific folder upload the kml file and open okay so now after the uploading you have to click this button that is the convert and add elevation okay just clicking this point and after fifth time it will give one you know ah gpx file link which can contain the x y and z dimension so if you click this link you will able to download this and save it in the specific folder and i am keeping the name as it is okay so our second step is done now our third step is to go to the tcx converter okay so it is uh it is you know one kind of software where we can convert the different kind of uh gis or gps based file into uh another format it's okay so here are the some ah you know some acceptable accepted formats represented here okay anyway so now we have to open the same file we just created let me go to the file and make sure to upload the gpx file because we have the corresponding we already attached the elevation data to this gpx file now open the gps file and after this opening it will automatically progress and you will see the altitude this is the altitude determine the elevation data corresponding to each lat long okay so after completing uh the converting the conversion procession process we have to save this file as a csv file okay so i am saving a csv file and name given the name as game csv and save and make sure that we don't need any kind of the safe reason so i am going to use the nose because we don't need any kind of the separation okay so now our uh you know cvx sorry csv file has been saved okay now the last step is to go to the qgi software now we are going to add this cld file into this qgis interface so for that we have to go to the layer button and then go to the head layer and from here we need to click the add delimited text layer okay because through this button we can add the uh we can add the uh you know csv file now click here and choose the file so here's the dame and csg file is that this is the name csv and after that you will see the you know the the sample of the data here okay anyway so now you have to assign the lat long and altitude values okay so latitude value uh should given to the y axis because you know let's actually latitude now actually increasing by following the or along the y axis and longitude following the x axis okay and the z field would be the alt you know the altitude version okay and makes you to keep it geometry as eps four three two six wgs 84 so this is the global geographic coordinate uh projection system following the world geodetic survey 1984 okay now i am going to add the point okay now you can see our point points have been added in the qgs interface now the next thing is to save this point as safe file so for that you have to right click here and export and save features as save file and give the file name to the specific folder i am giving name as point name okay now let's uh keep it as like that or maybe we can change the projection system here so we don't need to do the reprojection because for creating the dam we need to do the reprojection data okay anyway in advance we can convert the projection system here also so the utm projection system is 43 north in this case okay uh so it was earlier in the geographic coordinate system that is the eps g432684 now i am converting to the projected coordinate system that is utm zone number 43 north okay that is eps32643 anyway just okay and it will automatically edit the point here just makes you to check the properties to see whether the projection system has been changed or not okay the projection system has been changed and the unit is meter okay so you have to keep in mind but if you see the earlier version that is dim the projection in the unit is the degree okay so that mean it was in the geographic coordinate system so makes you to convert this uh data to projected coordinate system okay so the next thing is to do some kind of interpolation based on the altitude data okay so if you open the attribute table so we have the altitude column here so these information are actually the elevation data corresponding to each point okay okay we have to go to the processing toolbox and search for idw interpolation okay so here we will find this this is the base function that is the i2w interpolation and just click here and put the you know the point name this is the input layer and choose the altitude as a um in the criteria for the interpolation and makes you to uh make sure to specific these input layers that means that how we actually want to do the interpolation okay so for that you have to just click the plus button and automatically it will create or it will add the available vector layer uh into the input layer okay so for that we have just created the point name and altitude is that is the attribute and now we have to select the which type of interpolation we are actually wanted so for that now we are going to add the structure line because we are uh we want to create the contour on the basis of the uh output raster okay so for that the default coefficient the distance coefficient is 2.0 so i will keep it as a default okay the extent should be the extent of uh point name because i want to i want to create the raster with the same extent of point m and makes you to increase the cell size because it is 0.10 meter so it is very very you know high resolution cell size so it will take so much time so here i am going to hit 1000 as for example and now uh click the run button okay so after clicking the run button it will generate the dam and if you uh want to make 30 meter 40 meters or less than 30 meters you will create a 10 meter 20 meter anyway whatever you need you can do uh this kind of pesa resolution by adjusting the numbers uh here okay so for but it will take so much time for example if we give the 10 meter resolution then it will take around 20 minutes to generate the result so that's why i'm giving the thousand meter resolution uh that's why uh i have the result in a few of second okay so anyway this is the 100 meter resolution interpreted raster dame but we already created i already created the you know 30 meter resolution raster name here okay so if we after creating the raster name for visualization you just before visualization or maybe you have to just save the raster as save layer as and as a tip file okay from here you will you will can able to save the result okay so let me save here dame thousand meter okay so that rest of the things will be you know unchanged let's hit the okay and it is our newly created name layer okay so now if i want to visualize the data so go to the properties and symbologies and then from here we have to change the single red zebra colors and from here we are we are we we have to change the you know correct color ram anyway we can plasma is another option anyway so continuous maybe you can choose the equal interval and class would be five and just hit the classify okay so now our created name is look like that okay but we want to create the contour line also which will be overlapping uh on the area over the area okay so for that you just have to create the search the contour and then you will find the contour from raster under the white box toolbox okay so white box tools is in another add-in which i will show how to add in the qg as in next an upcoming video so so from here you have to choose the function that is the concrete from rastas okay once you choose you will have you automatically have the raster data on the basis of which you are going to create the contour and here i am keeping the you know for example 250 meter contour interval and the rest of the things will i am keeping at as different and just hit the okay so now you see our contour is generated so this is the output contour so just before doing anything i am going to save this contour and as a save file and name as dev onto 1000 meter okay so hit okay so this is the newly generated control just remove this file from here okay now if we see the attribute table we will see the height value okay so now i'm just going to create the or or or change the color for better visualization okay so i am making it as black okay so this is the beam line and i want to all i wanted also add the labels of the heights okay so again go to the properties and go to the labels and from here you have to select the single reveals and from here you have to see the height value okay and then apply so now you will see that the contour line and corresponding height okay so from here you can easily make a beautiful dame map from the google earth engine as well as the contour lines also okay so anyway here is another example i just created on the basis of the dim but the resolution is quite high so now you will see how it will look if we if we increase the you know uh special resolution from thousand meter to for say example 30 meter or 10 meter okay so it if you need better resolution dame then during the raster creation you will add uh you know the higher pixel resolution value so that's why you can have a better resolution date okay so apart from that what i am wanted to do i just click of the dam now i have the contour value now i want to visualize whether our data is you know correctly overlapped over the base map okay so for that i am used to i am going to use the open layer plugins or maybe quick match service any way you can use so from here uh i am going to add first example acry and acid physical let's see what happen so anyway this i think this layer is not available just to remove this layer again i am going to add the open layer plug-ins and from open street map and from we are going to add the open speed map okay so now you will see how the however generated contour actually overlapping with the base map okay so just i'm going to reduce the transparency to 50 percent for better visualization apply and now you will see the dim values as well as the contours which is just overlapping with each other okay so for the example uh if we want to see the river valleys okay you will see it is the actually the plane surface is this side that is the lower jewel this is the plain surface where we have the several towns and settlements like things and these are the very high altitude areas okay so this is the complete you know guide how you uh how do you actually create the digital elevation data with the help of google earth by using the tcx converter and also the qgis okay so anyway uh thank you for you know thank you for watching this video and make sure to subscribe this channel

Channel: Geography Lab (GIS & RS Guide)

Views: 8,610

Rating: 4.9130435 out of 5

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Id: j3XjySi7uas

Length: 23min 46sec (1426 seconds)

Published: Sun May 23 2021