layers ArcGIS

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Understanding layers

The key feature of any Geographic Information System, whether we're talking about ArcGIS or the old style mapping techniques of using stacked transparent sheets, is the concept of separating our data collection and organization process, into a series of layers that we can manipulate independently. ArcMap brings us concept into the digital age using this panel over here on the left, called the Table of Contents. Now, the table of contents describes all of the data that's currently appearing in our data view area, over here on the right. And it describes it in the order that it's being drawn in. So in the Table of Contents, I have this section up here called Layers.

And this is actually our data frame. Now, within the data frame of Layers, I've got a whole bunch of data elements. This bounding box one down here on the bottom is currently symbolized blue, and it appears at the bottom of my map. And then on top of that, I'm drawing graticules, and on top of that, I'm drawing some States and Provinces, and on top of that I'm drawing some Time Zones, but the time zones aren't currently visible. We'll get back to this in a second. Then on top of that, I've got my Populated Places, with these red dots. And on top of that, I've got my Airports being displayed with these purple dots. ArcMap displays all of the data layers, and the symbology options that I've chosen to display those with, all on the same list.

I can expand and collapse this view using these plus and minus buttons over here on the far left. So, for instance, I can collapse this down so I just see the name of the data layer, and not how the data's being presented. I'll go ahead and expand these open again. I can also toggle the visibility of that data layer by using the check box here. So right now I can see all the different airports in purple on my map. If I click the check box, that data gets removed from the map. I can turn off Populated Places as well, and I can turn on Time Zones, and I'll see that data appear on the map view. Let's go ahead and reset this to the way it was. I can also control layer visibility by using something called a group layer.

In order to get a group layer, I'm going to go up to this Layers name here of my data frame. I'll right click, and say, New Group Layer. Then I'll add this section here called New Group Layer. And this acts kind of like a folder. So I can go ahead and put stuff inside of it, and then control the visibility of everything at once. I'm going to take my group layer, and drag it down to the very bottom of my stack. And then inside of it I'm going to put my graticules. I'll click it and drag those down below group layer. And I'm going to take my bounding box and drag em, drop that down below as well. So now I have this group layer that I can control its visibility, and I can turn off both the graticules and the bounding box at the same time.

And you'll notice that they both get removed from my map view. Or I can turn that on and they both reappear. And I can collapse that group layer all together so I don't see the names of the data layers that are within, there. Now New Group Layer isn't a really good name for this. It's not describing what's inside of it, so I need to rename this. In order to rename something just select it once in the Table of Contents and then pause for just a second and then select it again and that field will become editable. So instead of new group layer, I'm going to call this Base Map. And the names of my graticules and bounding boxes, they need to be changed as well.

So these are coming from the names of the data files that supply this data. But it's not very descriptive here for my maps. So I'm going to do the same thing where I select it, pause for a second, and then click again. That'll make this editable, and I'll change this to Graticules. And I'll change this one to Bounding Blocks. And put in a space there. And once I select off of it it finalizes those changes. So now I've got a clean layers panel over here that's describing the data that's appearing in my data view over here on the right. Now throughout ArcMap, there's a lot of power to be found in right click menus. If I go up to one of my data layers, for instance this Airports one, and right click on it, you'll see a whole host of options that I can choose from.

Some of these include labeling features. You can see this is currently checked on. If I click on Label Features, that'll turn the labels off on the Airport section of my map. Let's go ahead and right click on that again and say label features to turn that back on. I'll right click on it again and we'll talk a lot about some of these options throughout this course. For now I'm going to go down, all the way to the bottom and choose Properties. That'll open up the layer's properties for the airports layer. Now again there's a whole bunch of tabs here that we'll get to in turn. But for now I'm going to stick to this General tab here. And on the General tab I have the option to set its Layer Name.

So instead of using our click, pause, click method, we were just using a moment ago, I can come in to the General tab of the Layers Properties and change the name there. I can also set its visibility here as well. So this check box here is equivalent to the same check box over in the Table of Contents. One of the things I do want to point out here is this Scale Range down here. Using the Scale Range, we can specify when our data appears on the map. So, right now if I move this out of the way a little bit, our map is really cluttered. There's a lot of airports and not a whole lot of space to display them. What I can do is specify to show the layers at all scales like it is now, or to not show the layers when there zoomed out or in beyond a certain scale.

So, let's go ahead and take advantage of this. I'm going to cancel this out for a second, and I'm going to zoom in to a point where I want to see my airports appear. I'll click on the plus sign. And I'll just zoom into my map quite a few times, until I get to about here, 1 to 30 million. This is the point at which I want to display my airports. So I'm going to right click on Airports, go down to Properties. And on the General tab of my Airports Properties, I'm going to say, don't show the layer when zoomed out beyond. And using the drop down list I can either select a scale or I can use the Current Map Scale. I'll choose that there and say Apply, and we'll say Okay.

And I'll still see my airports because I'm at 1 to 30 million scale, but if I click the zoom out button and I click once to zoom out, you'll see that the airports disappear. I'm going to zoom out a couple more times to 1 to 50 million and I'll do the same for populated places. I'll right click, go down to Properties. This time I'm going to say don't show the layer when zoomed out beyond, and I'll set the current scale for this as 1 to 50 million. Go ahead and say Apply, and then Okay. And now if I zoom out again, you'll notice I don't see my cities. So now I have a really clean map at small scales, but as I zoom in and get more area to my features, I'll slowly see my cities, when I reach a scale of 1 to 50 million, and if I click a couple more times and get to a scale of 1 to 30 million, that's when I'll see my airports appear.

So that's how I control layer visibility in various scales. Now let's go ahead and zoom out a couple more times. I'll get these to turn off. And there's a couple more buttons on the Table of Contents that I want to see. Right now we've been looking at the List by Drawing Order. In which case it shows my data layers in the order that they get drawn on the map. The next button over says, List by Source. And if I click on that, it will show me the data sources of where these data files are coming from. There's a group in the folder called, Data Files Global, and that's where my Airports, Populated Places, Time Zones, graticules, and bounding box come from.

And then there's a group within the Data Files Global folder, there's a geo database called States, and within that is the States and Province files. So, that's where that's coming from. So that's the List by Source option on the Table of Contents. The next option over is List by Visibility, and here we'll see all the layers grouped by their visible status. So you'll see States and Provinces, graticules, and bounding boxes are all visible. Out of scale range currently are my Airports and Populated Places. And not visible are my Time Zones, those are turned off completely. And then finally we have an option here called List by Selection.

And this will allow us to choose which layer is our selectable or not selectable, and we'll take a look at this in the next movie. So that's a tour through the Table of Contents. The Table of Contents provides the main directory for interacting with the individual data elements that will make up your completed map. By using the various View modes within the Table of Contents, you can easily see how your map document is constructed and where the data is coming from.

Understanding layers
Video duration: 7m 24s 3h 13m Beginner


Understanding layers provides you with in-depth training on Business. Taught by Adam Wilbert as part of the Up and Running with ArcGIS

Business Developer IT
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