[MUSIC] Hello again, and welcome back. In this lecture I'm going to show you a few different ways to compare rasters to each other Visually when you're working in ArcGIS. Specifically I'll show you the swipe tool, the flicker tool, and the pixel inspector. To start out, I'm looking at the same data we used last time and let's change the slope to standard color ramp here, a stretched classifier and just grey to white. And once I have that, I'm going to turn off the digital elevation model for a moment and turn on the aspect. Now, if I have the aspect layered on top of the slope, it's hard to take a look at both the slope and the aspect at the same time. I get sort of a hill shade effect from this, but it's not really telling anything about the slope. And maybe I want to analyze these at the same time, or I have some aerial imagery I want to take a look at too, but it's hard to see at the same time as this data, because it's so colorful. I could set it at semitransparent in the roster display options and the properties pain but sometimes that's a little wonky anyone see one at a time. This is where the swipe tool comes in. So in this case, I'm going to introduce a new window called the image analysis window that you can find under the Windows Menu, and a quick image analysis and up pops a new dockable ping that we can use. And again, this is one of those things that you would have seen if you took the first course and did the assignments. We used this a little bit, but we're going to use some new features in there right now. So to start with it has a lot of the same options that we have in our raster properties but they're much more quickly accessible here. So if I select my aspect raster I can select the brightness and contrast and things like that I can select in the raster properties pane. I can also select the color ramp and then use a powerful tool that we're not going to go through here called raster functions. These are also in ArcGIS Pro and while I want to cover them, they're a little advanced for us right now. But if you're interested in running custom functions that manipulate your rasters, Directly in the Display View. Check those out. For now, let's focus on the Swipe Tool. So if I select Valmire Aspect here up top, and then I click on the Swipe Tool, I now get this arrow in my table of contents, where depending on what side of the screen I'm on. If I'm on the right, it gives me an arrow left, if I'm on the left, it gives me an arrow right, and then top down, and bottom up. And so, if I I'm on one side of the screen and I click down, I all the sudden see the roster layer below it on the other side of it. And I can move back and forth and see how each roster changes so if I want to see fine details in an area. And note that maybe the aspect line in this area right in here follows even as it transitions from down low in the river to the hillside here. I can do that with this comparison tool. So it's a really handy way to quickly manipulate your visual use of the layers so that you can see what's going on in two different. And just like I said, I can select from different directions, I can slide up and down as well. Another way to achieve this is with the flicker tool which is right next to it. And what it will do is it will turn a layer on and off at a specified interval in milliseconds here. So 500 milliseconds, every 500 milliseconds it will turn this layer on and off. If you're sensitive to blinking things, this won't be that fast, but just be careful. So I'll click on this and it's going to turn my layer on and off, so that I can evaluate each layer. And in this case, I can focus on maybe an area like this and see how each raster looks compared to the other one as the layer flashes on and off. And then, I can click the button again to turn off the flicker tool. The last thing I want to show you is the pixel inspector. This is especially useful when you have rasters of different resolutions as well as categorical rasters. Sometimes you want to see after an interpolation process or something else, where raster pixel boundaries end. And we can kind of see it in here, but If I'm zoomed in really far, or I have giant square areas, it can be hard to tell, maybe, if this is two pixels tall or one pixel tall. I could assume it's one pixel tall, but maybe this whole area ends up being, actually, two pixels tall, and I just can't tell because it's all aligned and it tends to change by twos, or something like that. So if I want to confirm that I can use the pixel inspect which will also show me all the values. And to do that we need to customize our toolbars and add a new tool. So, if I right-click on the top there and go down to the bottom I can go to customize. And, under commands I can search for new commands from any of these toolbars and I can create my own custom toolbars this way. For now, I'm just going to add this command to an existing toolbar, but know that through this customize mode. You can create your own sets of toolbars for the common tools you use in a very similar way. So I'm going to search for the pixel inspector, and if I type pixel here it comes up. And I can just click on it now and drag it to a toolbar. And if I was to create a new toolbar over here, I could do the same thing to drag commands to that same new toolbar. The nice thing here also is that you can add commands that aren't necessarily available on existing toolbars. You are not just remixing toolbars but sometimes you're adding new features or adding things from menus. So one thing I'd like to do sometimes is have my selection toggles, toggling between add to current selection, and remove from current selection as a toolbar item. So I'm not constantly digging in the menus for that. So it's all up to you, it's all about your work flow, but you can create and customize toolbars here. So now, I've added the Pixel Inspector to that toolbar, and let's get rid of the Drawing toolbar so we can see it a little better and pixel inspector's here. And if I click on it I get a whole new thing on the left here. And let's expand it a bit so we can see a bit more about what's going on, and then collapse the table of contents. And if I click on the raster I now see the cell boundary outlines as I move my mouse around, but I also see a matrix of the values on the left side. This is really great if we want to be identifying values, but it just would be a lot of work to do all that identification. similarly we could do this with our digital elevation model, so if I turn off these other layers, and let's zoom out a bit. I can see my cell boundaries, even though interpolation has modified how everything's being displayed right now. And I can get all the values over on the left for the matrix I was just showing. The other thing I should point out is that it gives me the raw values which is the values stored in the raster dataset. As well as the rendered values which is the values it chooses for the color as it stretches the raster to meet our color ramp. So, the rendered values aren't the underlying analysis values, they're the color values. And the raw values are the actual stored data values in our dataset. Okay, that's it for this lecture. In this lecture I just showed you a few tools that help you compare and assess rasters visually in ArcMap. We looked at the swipe tool for assessing two different rasters as well as the flicker tool for doing the same thing. And then took a look at the pixel inspector and creating new toolbars and customizing them in ArcMap. I hope you find all of these really useful and I'll see you next time.
