Geodatabase domains

what we're going to cover today is creating a geodatabase and working a little bit with domains so to create a geodatabase you go to the folder in which you want to reside you right-click on that folder go to the new option and then select file geodatabase this will create a blank geode a base with a default name change it to something appropriate for us we're going to call it study area and then you're ready to add features or raster's or tables or whatever you'd like to the geo database and you do it the same way in which it was created you right-click go to new and then select feature class for our purposes we want to create a feature class that's going to be polygons you need to give the feature class a name so you type in the name and an alias and then be sure that your type is set to the appropriate one should be polygons for us then it is a couple more dialogues which will hit the first being identifying a geographic coordinate system for it rather than going through the selection process let's import one will import the one for the image from which we're going to digitize the land area so we'll find our image the one is currently on display in the background and select it import the geographic information from that take the defaults for the next couple dialogues and then it comes to a dialog where we see fields for a new feature class the default ones being object ID and shape here we should create two new fields one of which will hold a numerical value that will relate to the land-use information we'll call land use numeric and we'll make it a short integer the next field will call land use description and make that text I'm adding some default values on each of these as you saw I did Lane use number I had a default to zero for the language description which is text as I mentioned we're going to have it default to agriculture since class Cyril and agriculture will refer to the same thing when we're all done simply hit finish let's talk about domains if we look at the data management section and the toolkit for domains that's within there we'll find that there is one there for creating domains select the create domain tool and pop it up we'll get our dialog domains reside inside the geo database so we need to select the GL database as our workspace we then will need to give our domain a name we'll call the first domain Lane use code and we give a little brief description calling it numerical codes for land use types and it is indeed a it's going to be a short and it's going to be a range since it's numerical we'll identify a range of numbers that the code can be when we're done with that we say ok and we've created a domain inside the geo database we have one for the codes we would also like to create another one for the descriptive information again same geo database identify a name for our domain in this case we can call it Lane use description this is going to be a text field that's going to store a string for the description the land-use type so of course the field type is going to be text and it is automatically identified it is coded say okay and it adds that also to the geo database as a domain now we right-click on our geo database and go to properties that's where we can see the domains that we have just added if we select the first domain the numerical one we can set the range a minimum of zero and we'll make the maximum six so the numbers for that field to be valid numbers will fall between zero and six we want to do a similar thing for the next domain but since it's text it would be coded and what that means is we will actually put in every value that's possible so for the basic code we'll start out with something like AG for agriculture so we enter that in the first role and then we type all agriculture is the description we can do that for a number of other fields including commercial industrial public residential vegetation water all those types of things until we are complete so we have completed just hit apply and then ok to finish the updating we open up the properties for the layer we can look at the fields and this is where we're going to assign the appropriate domain picking the land-use number we go down into the second section and identify which domain we want to use for that particular field and we want to do the same thing for the descriptive the text information go down and in the domain section in the second section read our file that we want to use descriptor description two domains we hit apply and okay and the domains have been set to each of the fields now so now how do we use these so let's go up to editing to see how these domains help us so let's create a new polygon start digitizing I'll do a very rough job just to create essentially a polygon that's commercial industrial in nature we then open up the attribute information for that and you notice we have an Lu number we can enter in a number value for this one is going to be a commercial and then we can identify a language description notice that it there was a drop-down list of the descriptions available those were all the ones we had typed in you can pick and choose that way you don't have any problems with spelling and someone typing in something that isn't even in the list however if I type in nine for the number we know that's beyond the range of zero to six but it doesn't tell us that right away so let's go ahead and digitize a few more polygons and add attribute information in so we can demonstrate a little the use of the range and how you can use that to verify your data and this one we'll call vegetation when we get it completed since I don't not sure about vegetation number will pull the dial drop-down list so it's 0 1 2 3 and vegetation should be the number 4 but again let's make it an obviously wrong number and make it 11 we'll do one more polygon and then we'll take a look at what we have let's do one of water so just a section of water along here digitize that in close it off and again update the attributes this time if we do the description first we see it's zero one two three four five water is five put that number in and they match up let's open up the attribute table and you can see that yes we have the numbers and we have the description but obviously some of those numbers are out of range the range was zero to six in our domain now we couldn't get wrong in picking description it only gave us those what we obviously could have at their range but there's a way of checking it if we select all the polygons and use a function on the editor called validate features it will tell us that there are two features that are invalid according to the domains and we look down there and yeah we can see the two they're selected we could look at the the fields that we updated indeed one is the nine is wrong as well as the loan and then we can simply change those values we can open up the attributes click on the nine and see that it should be indeed it should be one click on the vegetation polygon and say hmm yes vegetation that's zero one two three four and make it four update those we can verify that by again selecting all the polygons run the vert from the feature validation option again and all features are valid so that's how we can use domains to set up a range of data values that are appropriate as well as descriptive information and text listing from which to choose our attribute information

Channel: Iris Cornell

Views: 11,750

Rating: 4.9183674 out of 5

Keywords: Geodatabase, domains

Id: MYvarQDkBig

Length: 12min 59sec (779 seconds)

Published: Wed Jan 05 2011