Flood Inundation Mapping Using Remote Sensing DEMs and HEC-RAS (for data-limited areas)- Part1

in the name of God I'm Asar aan and in this part we are going to talk about the usability of uh remotely sense spased them for fla inundation mapping and and moreover we are going to learn how can we use to uh uh to learn how can we use DS for extraction of river geometry okay first of all we should download or Pro provide a suitable them uh for our case study you can use topographic map and create them in GIS environment or you can uh download Open Access and public uh access dams such as srtm Aster and allos for extraction of uh HR 1D geometry okay uh in this part we will investigate uh both topographic maps and remote sensing base DS uh for extraction of uh River geometry and uh flood modeling in ha okay let's go to download remote sensing base DM uh in this figure you can see the open topography site uh open topography website which is one of the best uh sites for accessing uh the high resolution and low resolution DMS okay in this uh website data data sets are categorized in two uh main parts the first one is high resolution DS and most of them uh especially is are for United States of America or England or some parts of the world uh while the low resolution DS I mean srtm Aster and all of stems are public available and exist for all countries and all uh area in the world okay in this site we can we should go uh to the homepage and in in this first P you can find uh more uh information about uh this website and the topographic data set with different resolution okay I go to the data menu and select data catalog okay as you can see uh in this website uh the data set are categorized into different uh tabs the first tab is high resolution topography uh which is contain a different uh uh high resolution dams for a specific area uh located are located in United St America Australia England and other parts of the world uh and okay we don't uh use these Dems for our cases because in most developing countries we don't access high resolution DS or topographic data set and therefore we can use these data set for our case study especially in developing countries Asian countries African countries and Latin America countries uh that's suffering uh to access high resolution uh data sets uh and uh this tabs is for USGS United States of America uh waterers shed and regions uh we should go to the global and Regional Dem in these tabs as you can see uh we are different them s sources or elevation sources uh some are about cm and some are uh 9M for example USS have uh 10 m 30 m and 1 M uh this type of data especially uh exist only for United stat of America we don't use this data set for in this uh course or in this uh topic we should go to the row of five 29 uh NASA Global digital elevation demm Global bimmetry and topography at uh 15 Arc are suitable for capturing the Topography of uh Lake uh and free surface waters ocean C and other uh water bodies uh moreover allos word cm demm is one of the best uh dim sources for extraction of elevation uh of the ground okay I will download the DS of this data set right click and open in the new tab okay uh if you are living in a developing countries European countries or United State of America you can download 30m or one meter DMS for your case study but in this uh course as I mentioned we want to use these stem for uh geometry extraction cross-section extra extraction and running the Hass model okay I will go in this page and you can find all about this uh data set and information about the project uh of allos this project is the Mion uh Mion of NASA and Ja jaka which is done from the 20 20 uh 26 and 2011 with the ctim resolution and the wgs 9084 data okay in this figure you can uh see the area uh that covers by that covered by uh allos okay I will go to aw3 and click on this button and you and you you will go to the next page and you can see uh some settings that can be done uh in order to download the them okay uh unfortunately at this time we can't see the Google sors in background of the picture and uh okay there's no problem we can use select the Orin and set the coordinates of our case study manually okay I will go on this area and select the region by clicking from upper to the right okay I want to download the DM of this area okay it says that this area uh is approximately about more than one uh uh 100,000 kilometers and therefore we want to reduce the area of this area we want to download okay I will click manually enter selection coordinates and therefore I can minimize or I can customize the area I want to download okay X Min minimum and x max okay I will enter 60 and why minimum the minimum y coordinate and the maximum y coordinate from 26 to for example 28 okay I C validate coordinates and estimate area to reduce the area I want to download okay you can see the area is decreased significantly and we can download a smaller and specific D for our case study okay in the next steps you should Define the data output format uh this is default format and I accept this uh format Jo however you can use arasy or IMG format I think this is a better choice okay in the next steps we don't need to check this uh options in the job title you can you should uh enter job title title however these are these data are completely optional and don't affect the downloading processes however I want to enter data I job title I will enter assistant professor uh job description flation mapping ination mapping and finally you should enter your email because uh open topography s will send uh download L to your email and also you can see the download L on the website okay I will enter my email and press the button submit we should wait to complete the downloading processes I think it after a little bit second the downloading uh will be provided uh however it should be noted that you don't don't need to go back to your email and find the downloading because after finishing the downloading processes you can uh you can see the download link in this website okay we should wait to complete the processing download okay uh you can see the downloading processes is completely done and uh uh file is about 60 uh excuse me 36 megabyte and in this uh picture you can see the visualizing products in Google s contain low and high lens okay I will download I will click in this link and download the data set okay I will download this data set okay it's download downloaded very fast okay let me go to the folder and open this data okay this data set is available here okay the next the next step is to extract this uh download the layer I will uh I should right click on this uh file and click extract here okay you can see only output a3d ct. TF file okay how uh should we see this stem we should only open AR GIS environment you can use quantum GIS or saga GIS or air do or other related GIS environment however you know AR GIS is one of the most popular and widely used GIS environment in all over the world okay in this uh in this environment uh I go to the add data and select add data and go to the related folder if you don't uh have these folders don't worry uh you should only click on connect to the folder and in the desktop or related drive you should uh you can select the desired folder okay uh I set my uh uh Direction into the desktop paper and select okay as you can can see in this folder we are two uh files one is a folder with the Dam's name and the second is output a Tre which is located here okay I select add and wait to upload the them press okay and after a little bit second a second you can see the downloaded them okay the elevation value is ranging from this value to this value you can change the color of the stems simply by right click on the output aw3 layer and in color ramp you can select a suitable color ramp for example I isolate color from red to blue okay okay you can see elevation variations and Highland and lowland and moreover Rivers which is located in this picture okay you can completely identify uh River Network and Overland area Okay in order to be as specific in this course uh previously I I've downloaded a them for a specific re with the name of SAS and I will discuss the hydraulic simulation using this data set let me to upload this them all all raw okay okay I will change the color of this data set okay I think this is the good color ramp composition okay as you can see in this D we have a main river and a other uh sub okay I want to extract River geometry for this part let me to show okay let me activate the draw tools and show you uh how area or the extent of our simulation area okay let [Music] me okay come on come on GIS okay as you can see uh I created a polyline around the river and I want to model only this part of the rivers and however you can use uh all parts of the world for inition mapping but in this case we want to model uh uh acas flood n mapping only for this part of sarbas reverse okay we should uh extract uh only DS uh in this area okay for doing this task we should let me close it this uh tools uh in order to extract a specific DS from a large DM you should first of all create uh shape file which is which defines the boundary uh of your DS okay first of all I I I should go to catalog I mean our catalog and in desktop go to the paper folder right click on this folder select new and select shape file okay in uh uh this part we should Define a name for our shap file I will send a I will type A boundary boundary okay boundary feature type is polygon and we should select a description or uh coordinate system okay you should uh select uh decimal degree coordinate or UTM uh coordinate system for your project okay uh first of all we should we should use geographic coordinate system and right click on this and go to the V and select wgs 984 okay okay uh as you can see when the mouse is crossing or flowing over the DM in this section you can see the coordinate system of this data set as you can see this data set coordinate system is based on decimal degree in order to uh rever andot uh study we should convert this coordinates system to metric system I mean you know one of the most popular uh metric coordinate system is UTM however there are several unpopular uh coordinate system in metric but in this uh case study I want to convert decimal degree to UTM okay uh before uh converting this Dam I should clip uh D stem and after that I can we should uh we can convert the coordinate system okay let me to uh create the boundary for my them let me close this extensions right click here or right click here and select editor editor editor editor is here okay uh click on editor start editing okay excuse me okay excuse me for the disconnection of my mouse okay select the create features and then select boundary and I started to digit our only main river P okay I think this part is only suitable for in this case Okay after finishing the digit uh digit uh you can stop editing and press the yes button to save your edits okay I'll will double click on this layer no color Okay red color uh black color Okay I want to extract uh DMS only in the boundary layer okay let me to close this and this up options in the search uh menu you should find or explore uh the extract by mask task in GIS environment or other related G en environment such as qgis and Saga there are similar tools that you can uh clip your them using a shape file okay I'm entering extract by mask okay X by mask is one of the uh tools of special analyst toolbox and select this and click on extra by mask special analyst this is the tools for uh clipping the them using shape file okay uh in input raster you should select alos alos R them this is I think uh because of the uh large volume of this file the loading is a little bit time consuming and in the input rter or feature Mass data you should select a shape file uh I mean boundary layer and the output rer is the our output okay let me select the desire folder paper and this my alls in okay save it and press okay okay we don't need these layers and therefore I I am checked in this layers but uh therefore we only use these thems okay let me change the color okay only we need to use these DS for for inundation mapping and R extraction geometry okay as you know this layer is based on decimal degree coordinate system and as as I mentioned before we should uh convert these stem to UTM in the source tab you can see the dimension cell size you know these values are in decimal degree and this is the coordinate system okay how can we convert this them to UTM them okay in the tool and search uh part we should type again projection projection or project okay uh you know there are uh different tools with the project name you should select only project raster data management this uh tools project data management is suitable for shape file uh but only for transferring or converting or changing the coordinate system of a rer layer you should use project rter or data management I select this layer this tools and raster project okay after a little bit second the desire tools will be appear okay in the input raster layer you should select your uh clip or extract it by mask them you know this is automatically select the input coordinate system GCS geographical coordinate system which is it in decimal degree and we should select the output I should type my alos underline UTM which is in metric coordinate system okay the output coordinate system you should select a coordinate system you should go to the project you know in geographic coordinate uh systems there are several uh decimal degree based coordinate system and in Project coordinate system you can find metric and ftic or uh us customary C coordinate system in this section I will click uh this section go to the UTM and in different datums you should select wgs 19084 and you should uh you should be aware of uh the location of your country or your projects in the world you know Iran is located in the North Hemisphere and for Latin American uh students or uh some African student you should select southern hemisphere in this uh project because this River is located in Iran and Iran is located in North Hemisphere and I go to the down and select the suitable coordinate system uh this uh project or this River is located in zone 39n and select okay you know after converting a decimal degree layer to metric the cell size of them is about 30 m or 32 M I select okay and G start to converting this okay uh the color is completely different I will double click Slayer in symbology table you should select a search don't worry and select the related color okay this is you can check the coordinate system is be okay right click on the layer and select property and go to the source Tab and now you can see the cell size of them is in meter and the coordinate system is Ws UTM Zone 90 3n okay okay uh in this uh in G environment uh we don't need to do any task and we will go to the H and extract the uh River geometry okay uh I hope you have a good time and in the next part we will talk about how can we use ha for extraction of geometry data set based on remote lens DS

Channel: HydroAI

Views: 7,003

Keywords: HydroAi, Azizian, Artificial Intelligence, Hydrology, flood, HEC-RAS, remote sensing, river geometry, RAS Mapper, flood hazard mapping, inundation mapping

Id: Bc9sGLxBG8A

Length: 30min 38sec (1838 seconds)

Published: Mon Dec 04 2023