Georeferencing with Arc GIS Pro

hi all beer back so this week's topic is geo referencing we will be looking at this video in two parts in the first part well sojiro fencing can be defined as providing a locational coordinate for an image so ice to place it in a real-world location on the GIS framework this image that can be a satellite image or a topo shield or screenshot of Google image any image that has some information about the geography when you put it to your GIS framework that is your GIS software it has to go sit on the particular place that it's giving the information about most of the times this won't happen because the coordinates won't be defined so for which we will have to be doing this process called your referencing so this process of geo referencing it involves three main steps one is to provide the control points all the locations second one is to a lot of suitable geographic coordinate systems which basically defines the where aspect of your map and providing the suitable transformation based on the number of control points ideally we should have a minimum of at least four control points more the control points higher the accuracy so based on the number of control points you will have to pick the transmission that's the first order so the third one is to verify the accuracy after your map is reference to a real-world location it is very important to verify its accuracy so this process of geo referencing can be through many ways one is to assign control points or the location to a particular pixel of your raster image or if there is an image that is already referenced to a real-world location based on that image also you can be referencing your new image that we you will be bringing on your J's framework or if you have the location coordinates on an excel file you can convert it into CSV you can import it and you can so in this video we will be looking at one type that is assigning the control points in this tutorial we are going to georeference a topper sheet using history our das core software this is the toka sheet of the place in Maharashtra situated in India this we are going to dereference it using the RDS for software for this first of all we need to import the data to import the data we have to click on this map add data we have to select the data we need to browse through the folder in which the toka sheet map is there in the form of jpg we'll select that and click OK now the tapa sheet is added into the JS environment this should ideally be present somewhere in this area but when we right-click on it and go to zoom to the layer if we can see it is situated somewhere in the water body this should be this is because this is not at your reference now we need to start geo-reference using the coordinates given on the four corners of the tapa sheet this is one of the coordinate likewise here one coordinate under the other two corners but what is the cordon which point does it exactly refer this coordinate is for the intersection of these two lines exact the the center point of this should be taken for the geo referencing so now go to the imagery geo reference before doing the geo reference you need to set the coordinate system go to SRS by default it will be in WGS 1984 web Mercator now change the stood geographic coordinate system world and WGS 1984 this this coordinate system is accepted worldwide in the further videos we will see the concept of coordinate system in the in our further videos again zoom to layer now to start the geo referencing we need to add some control points prior to that turn of this auto apply ad control point now click on add control point zoom into the exact intersection zoom as much as possible such that we will select the exact point to reduce their left click here zoom out and then right click on the same point now it will ask for the target coordinates the coordinates and degrees and minutes should be entered in decimals like once we have another option to enter in DMS means degree minutes ins seconds if we shall ask us to enter in enter the wrong longitude and latitude values in degree minute and seconds I prefer entering the target coordinates in decimal system for that now we need to convert this longitude value of 74 degree 15 minutes to decimal coordinate how do you convert this this 15 minutes should be converted into decimal format each week and this of 60 minutes so this 15 degree by 60 will give the decimal value so now we have to enter here as 74 point this decimal value is given by 15 divided by 60 that is 1 by 4 that leads to 0.04 you mean seventy four point two five likewise for the latitude value we have it is eighteen point eighteen degree 15 minutes so 18 degree eighteen point two five degrees fun and click OK this red symbol shows the point which we have selected and this green symbol shows the target coordinate target coordinate point likewise we have to do for all the four points zoom into the PowerPoint select the exact one zoom out right click then enter the target coordinates here seventy four point three zero means seventy four point five how did we get this point five thirty by sixty eighteen point two five similarly go to the third one this point selection should be done very carefully because this leads to the error if this is not done proper this leads to the error in jails error propagates so we should try to reduce the error from the very first at seventy four point five is the X and eighteen is the y coordinate similarly we should go for the fourth one the zoom in left click on the point zoom out the fourth coordinate is seventy four point two five and eighteen we cook it as we have selected all the four points and given the respect to coordinates now we need to apply this when we apply it will automatically go and get geo-reference so right click on the layer zoom to layer see this is the cocoa sheet which which got the reference now to visually check if it's correct or not we'll just puggle off and on the layers so that we can see if the layers are overlapping or not there is some major ever passing over this we will zoom into this layer when we turn off see this rework is exactly matching with the top washing layer so visually we got to know that ours is correct we will go into the another Road intersection zoom out and check and see oh this is a river this one is a river this is the road intersection the both are matching perfectly but how to quantify this if the geo-reference is correct to what extent it's accurate or not we need to check the for RMS error the forward RMS error we need to check the basic come rule is that the zero reference is said to be accurate if the forward RMS is zero point zero zero zero and some you mean streak triple zero and some value then it is said to be accurate if this value is more than 0.0001 then you need to redo the whole thing again so this is the differencing of it opposite into the GS environment in the next video we'll see the g referencing in various methods for more GS 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Channel: GIS for Geeks

Views: 4,094

Keywords: GIS, Geographic Information System, ESRI, ArcGIS Pro, Geo-Referencing, Image Registration

Id: _aYDQhfqVS8

Length: 10min 27sec (627 seconds)

Published: Sat May 23 2020