Geography 212: Using definition queries in ArcGIS Pro

hello to 12 students today I'm gonna show you how you can use a definition query to limit the results you see in a layer you you have displayed so here I have a layer that has the provinces and states of US and Canada and let's say it had too much information that I didn't want to look at if I was only concerned with for example the United States of America and not the provinces of Canada should I go download a whole new layer or can I just use this layer well you can actually just use this layer and choose not to display Canada and I'll show you how so first we're going to open the attribute table and take a look and we're gonna find a field that differentiates each of these states based off whether it's in Canada or the US so as you know each of these shapes is corresponding to a row and you'll see that one of the first things that each of these rows has is it says what's country it's in whether it's Canada of the United States of America in this column called admin so what we're gonna do is we're gonna right click on it we're gonna go down to we're gonna right click on it under the content tab the layer or to go down to properties and we're gonna go to this one definition query and we're gonna click new definition query so what we're gonna do is we're gonna say we're and we're gonna choose the column name we're admin is equal to and we're gonna say there's two options we're gonna choose United States so we're saying keep the ones we're admin is equal to the United States of America watch happens if I click apply and ok it got rid of all the Canada at once now let's say we want to do the opposite what if we had tons of countries but we only wanted to we wanted to show all of them except one for whatever reason we could say edit and I can say is not equal to I'm gonna click OK and instead it's gonna show Canada ok so we can also use definition queries and different ways there's a lot of options we have right here I'm going to show you a very useful one includes the values includes the values allows you to choose multiple values so let's say I wanted to choose for example if I wanted to choose a few states and I knew their names let's say I want to choose our Pacific states which include which include Alaska Hawaii California Oregon and Washington I could go find the column that has the information it's gonna be named and it's here at the top and I say includes the values and here I'm gonna choose all those ones I'm gonna say Alaska and I'm going to say California now I'm gonna find Hawaii Oregon see I'm just checking them and Washington okay and now it's gonna include all of those ones and those are the only states that are showing up all right so we can also use numbers fields that have numbers you'll recall in a previous video we created a field called area which is the area of states in square miles let's say I only wanted to show states that were above a certain square mile to do that I'm just gonna go edit this I'm gonna say I want the only the states where the area is greater than oh and let's just try 100,000 and see what we get I don't know if this is gonna show us anything all right so you can see it's only showing the sizable of states or provinces that have a very large area in square miles okay so let's show you a few more things about definition queries if you want to keep a query but you want to like just not display it for right now you just uncheck this click OK the query still exists but it's not activated at the moment let's say I wanted to have two different criteria let's say I wanted to sit be in the United States and I only wanted the ones that are above 100,000 because right now it's show showing the Canadian ones too which is all of them apparently what I can do is I can go to properties and I can actually edit in here and I can add a clause and I can say area has to be greater than 100,000 and the admin has to be equal to the United States of America see and now it's showing only the US ones now take note and means that both criteria must be true to show the given state okay so it has to both be larger then it has to both be larger than 100,000 and it has to be the United States you have another option you could say or this is different because it will show anything that meets either criteria so if I say or and click apply now will show everything why is it showing everything well because it shows all the United States no matter what because at least one criteria is fulfilled and it's showing all the Canadian Canada ones because all the Canada ones while they aren't in the u.s. they fulfill the other requirement so what happens if I switch this to and it has to be in Canada now it's showing all the Canadian ones because they all fit at least that criteria and it's showing the United States ones that are above the certain area because they don't fit the Canada criteria but they fit the criteria that they're above the approximate area that we're looking for so that's how we can use definition queries to show and not show certain things in our layers

Channel: HBLL Geospatial Services & Training

Views: 660

Rating: 5 out of 5

Keywords: BYU, Geography, GIS

Id: 7DhChyWf4b0

Length: 6min 29sec (389 seconds)

Published: Fri May 08 2020