ARC GIS - Catchment Area Calculation (PART -1 Digital Elevation Model)

arc GIS this is the software that I will be explaining in the lectures from now onwards and this is going to be a series of the videos that will be having different steps and different functions of the arc J's so basically we will be performing a realistic example in this software ArcGIS so by the end of the video those people who want to know about the ArcGIS and want to clear their concepts and who want to know about the different tools of this software ArcGIS who wants to know about the functions of the software different attributes and the steps and everything this video is definitely for you guys and those people who want to learn how to calculate the catchment area and want to perform it using a software in this video is also for you guys so let's start the process so because the video is going to be a sort of a lecture and I'm going to be explaining it using the screen here so and I will be explaining each and every step in detail so that's why the videos are going to be a little longer so instead of having one long video of one hour or something I will be dividing it into different short videos so you guys can just watch them accordingly like video 1 video 2 or whatever I have just named them so let's start it so in this first video we just explain I will not be opening the software but I will be explaining the other steps and all the steps and some of the steps there are not including the software for example let me tell you the first step is coordinates so you guys need the coordinates now many of you guys might not know what is what what sort of coordinates am I talking about so if you know the concept of the catchment area then it is fine it will be easy for you to pick the coding but if you don't know the concept of the catchment area then you guys can just watch my previous video and you guys will definitely understand it in in a better way and now I can tell you what is coordinate I'm assuming that you guys know about the catchment area so let me show you the catchment area for dam this is a realistic dam that I'm taking as an example and if you see the dam in this map this is a realistic catchment area this is the dam site and this shape that you are seeing is the catchment area that have been calculated by the people who are working in that time so we need to cover yourself this point this specific point and for this specific point we will be finding the catchment area so similarly you guys can just find any coordinate or any dam in your country or any location for which the catchment area has been calculate or you want to calculate it for and then accordingly we can find a catchment yes I'm taking a dam site as an example and later on we will be comparing our catchment area with this one and we will be comparing the value of the area as well that is 42 square miles and these are the coordinates of that point this is basically the inlet of the dam from here I mean behind this this is the river these are the tributaries and from this River and in the middle of the river there's a dam and then the river water is passing through the dam or maybe stop there or may be being used for any irrigation purposes or something like that so the first step have been done first step was getting to coordinates the second step is digital elevation model so what is the digital elevation model basically if you open any sort of a map of the earth or if you open the Google Earth or something so you see this is a sort of a complex configuration it just having water as having greenery and brownish and every sort of color layers in this image so now if you see there there are details there are different type of details in these maps now the ArcGIS software that is related with the hydrology and civil engineering sort of works it is not it doesn't require this much of detail it only needs the specific details regarding your project or your task that you want to perform so why give it so much complex details and waste your time of processing and everything make it easy for the software for that purpose we need the digital elevation model now what is the digital elevation what it is simple once you locate your location for which you are trying to find the of which you are going to be using the location which you are going to be using once you locate that then you guys just convert it into a digital elevation model a digital elevation model is sort of a black and white image in which the black and white color shows you the intensity of the depth and elevation of the of the terrain there so if there are mountains or if there are deep valleys so they can be represented that and on the basis of that we can know whether the Walker is going to be in the in the catchment area or whether is it not going to be in the catchment area so because the Walker forms a catchment area when there are there is sort of a valley surrounded by mountains or high elevation Peaks so that's why we need the elevation sort of a configuration image that is a digital elevation model so let's start the process the first step is and so you need this software or I mean this website for the digital elevation model so this is the easy step this is just one or two step method the first step is add coordinates now you know what coordinates I am talking about I am talking about the coordinates that we just took these were these for the dam site for which we are trying to find a cache material so 2014 18 not 71 2404 East I hope you guys can just find any coordinates of your dam in your country or any point for which you guys can just be interested in right take those coordinates and enter them in there so 34 18 18 north and 71 24:04 east ad now you guys know this is the location and this is just a point this is just one now this is from where you guys need to understand a catchment area is two dimensional it is not a point it is a whole sort of area to narration area so definitely mean we need to take a region with us not just one point we need to have the whole region with us right so what we will do we need other points as well so for that purpose what we will do if this is our point if I take the whole window that I am watching in front of myself you see this window dis dis Holman if I take this with myself then I can locate this specific point later on using the ArcGIS software but I need to take the whole region with myself now why am i taking the whole region with myself if you guys don't know so let me just quickly tell you why look this is let's look this is this damn site is the location that I just entered in the website right this was the one point but if you see the catchment area this whole catchment area this is not one point this is the whole region this is the whole area so that's why you need to take the whole area like this you need to take it like this not just one point you need the whole area so that's why I am going to extract the whole image here with myself here so what how we can do that we can just first of all zoom in or zoom out if you zoom in so you will be getting more into the earth so for example right now you might be watching different countries if you zoom in you are entering into cities in few zoom in you are getting into the your residential areas if you zoom in more you will go to the specific point like for example your house so you can experiment don't move it okay so you can expect the catchment area to be bigger or smaller or maybe you guys can estimate that how big your catchment area is expected to be and accordingly you guys can zoom in or zoom out the map now if you guys got a little bit confused so let me explain that to you look for example if you guys in the end when you guys find the catchment area in the end and the catchment area shape is something like this so what does that mean it means some area the upper part is missing it is missing so this is not the correct way but if in the end for some people the catchment area was this now what does that mean nothing is missing everything is included in the window do you see everything is included so nothing is missing no area is missing so this is correct we will accept this so what is going to be happening here you guys don't know what is going to be the final output but you guys can expect or you guys can estimate that how big your catchment area can be so I'm expecting it that you know don't zoom it out too much zoom it a little bit in and I think this this window size will be fine it will be somewhere in this window if it was not then I will in the end know it just like this and I will again do the steps and zoom it out and in the end I will get this sort of a configuration right so for the time being just estimate and just zoom in and out accordingly and just select a window side now what you going to do once you select a proper window side click on the use map once you click on the user's map you see this red region this is what I have selected if i zoom out so this red region will be shown more clearly look I assumed out so this is the red region at I have selected if i zoom in zoom up right now I'm going now where is my location my exact location is somewhere here somewhere here but I will locate it later using the arc GIS software it can be located now the next step is extracting it and converting it into digital elevation model so how we can do that click on the datasets click on digital elevation then SRTM then the first one as RDM one arcsecond global and results then you have your digital elevation model do you see this now click on this green and the sort of a download option click on it and you can select the last one geotiff one arc 24 whatever and you guys can just download it select a folder for yourself so I'm waiting for it and it is going to be taking a little bit of time so come on I play games too much here is the catchment area and you can you guys can just save it I have already saved it so I'm not going to save it again you guys can now save it right I'm going to cancel it because I have saved it already and yeah I have forward one thing you guys need to create an account for yourself before doing this so you guys can just create it in one or two minutes it is free of course nothing is in you you just need to sign up and log in ok after you have downloaded your catchment your digital elevation model so we have done the second step as well now the third step is opening the arc GIS so I have opened the ArcGIS now I will close this and I will open the new window and select the folder for which so we will continue this step in the next video because I think the video is getting bigger and I think it is not a good option so we will continue it from the next video so open the next video thank you very much

Channel: Ahsan Khan

Views: 1,785

Rating: 5 out of 5

Keywords: arcgis, catchment area, hydrology, watershed, DEM, digital elevation model

Id: p5gyHx3gg0g

Length: 12min 40sec (760 seconds)

Published: Wed Jan 01 2020