It's possible to have two different maps with two different projections on the same page or the same map layout in ArcMap. Here, we have one DataFrame with data for UConn in my custom map projection. So this is a dataframe here and I can just move this up to one side of the page if I want, I can center at a gain by doing that, for example and then, I can say, insert new dataframe. So now I've got a second dataframe that's completely separate from the first one and I'm not doing a great job here of lining them up exactly. I'm just kind of showing you how it works, but now I can add different data. I can add the same data, I can have different data. In this case, I'm going to add my Canada data that's been put into production of equal area conic, and I will drag that into my second DataFrame. So now I have two different maps, two different DataFrames, two different projections that I can use, and I can mix and match, I can change symbology, do whatever I want with that if I so choose. So for example, I could just copy the data from this Dataframe and right-click and say, "Paste layer" and now I've got the same data in the second DataFrame, and you'll notice that it automatically reprojected the data to match the DataFrame projection in the one for Canada. So it's reprojecting it on the fly as we say. It's not changing the file, it's not exporting it or writing anything to the file. It's just said, "Oh! This doesn't match. I'm going to do the calculation to see what it would look like, if it didn't match and then show it that way." So that's what's happening here. So now we have two different DataFrames, two different objections that can be quite useful to be able to do that. So sometimes what we want to do, is add an extent indicator to a map. What that means is, what I've got here is my map of Uconn up here and I want to show where that is on my map of Canada. So, sometimes it's called a locator map, if people aren't familiar with the area to kind of know where is it that I'm actually looking at here. So there's a way that we can do that in the software and so let me just show you. So all I have to do is right-click on the Dataframe that I want to add the extent indicator to, and select properties, and there's a tab here called Extent indicators. So, I've got my layers DataFrame. I can add that here. I should probably give my DataFrames better names like Uconn in Canada or something like that. But let's just go with this for now, and if I just say Okay, that's my default extent extent indicators. So, the software by default has given it this kind of thick red line, and what this is, is it's literally showing exactly the size of the area in my Uconn map. So for example, if I made this map smaller, the extent indicator is updated to match that on the map on the bottom. If I make it larger, it gets larger on the bottom. So that's something that can be useful to do. Also for example, if I zoomed in on one part of my map here, so I'm changing the map scale, the extent indicator on the bottom will match that as well. So it's a dynamic function, it's matching the geographic extent, the scale, the size of the DataFrame on the other map so that if I was just making a map of part of the Uconn here, then it would show that as the extent indicator in the map on the bottom. There's lots of different ways to use this. It's not something that always gets used with there's different ways of creating locator maps, things like that. But I just wanted to add this in here to kind of show that you can have different DataFrames, with different projections, and you can help your map reader interpret what they're looking at a little bit better by having the option of adding that extent indicator in. So, you'll notice that the extent indicator is on this angle here, and that's because of the projectionist being used. This is a customized projection with a central meridian. That's sort of right down the middle here, so that our area that we're mapping is centered, but when you take that same area and put it on a conic projection like we have on the bottom here, then the extent rectangle is going to reflect the fact that that's part of a conic projection, like that and it's going to look a little bit different you have to decide whether that's useful to you or not. Is it more confusing to somebody to see it that way, but the software is really just doing it the way it's meant to you, and saying well, this is the area that's mapped on this one projection. If you use a different projection on the bottom, it's going to have a different look to it, or a different angle based on where that is located and how that relates to the projection itself.
