TutorialMap4

Hello PSC 216. This is your tutorial video for our second map of this week. This map is a little more complex. We're working with the pairwise buffer tool. There's going to be some new layers that you're going to be introduced to. Um, and we're also going to be working with a tool called pairwise clip.

Our goal for this map is to calculate the number of shootings that occur within 1,000 ft of New York City Nicha properties. So, we're looking to see if those hot spots we visualized in our third map match up to where shootings are occurring within parts of the city. And we're looking at whether NICHA buildings are part of this equation.

So once again, make sure you've obviously logged into a portal, logged into ArcGIS, start a new map, call this one your last name, map 4, and as always, give the software time to start up. Just exiting out so we see our catalog here. Add our data folder of course and turn off the topographic and hillshade layers for now.

From the polygons, I'm going to bring over my NTA layer. And I'm also going to bring over a new layer that we have not worked with before. And that layer is the Nicha development layer. This is a footprint file of all Nicha buildings in the five burrows. So bring this layer over and make sure it is on top of your NTA layer. We're interested in the locations of these buildings so that we can add a buffer so that we can measure a thousand feet. That's the real layer that we want to hold on to is that buffer layer.

In order to create a buffer in ArcGIS, select the analysis tab and in the tools group you will see pair-wise buffer. Select the tool and when you select a georocessing tool, the georocessing tools menu opens up right over the catalog. So this is the georocessing tool pair wise buffer and what it's going to do is draw a buffer based on the measurement we provide. The input for our buffer, the Nicha development layer. The output you can leave the default name. We will rename it later. The distance 1,000 ft and we're going to use US survey feet. The method is geodessic shape preserving. Remember the earth is flat. We are taking or excuse me the earth is flat. The earth is a sphere and we're taking that sphere and putting it on a flat surface. So we have to adjust for that. The earth is not flat. That's only for uh weird people in Colorado who still think the earth is flat. There's a group out there. So no, your professor does not believe the earth is flat. It is a sphere. All right. Um the dissolve type, we're going to dissolve all the output features into a single feature. So what's going to happen is the software is going to measure a,000 ft around each of these Nicha buildings and then create a new layer so that we know within that layer we're within 1,000 ft of a Niga building. Go ahead and run the pairwise buffer tool. And what you're going to notice is a new layer has been added.

Once you have run the pair wise buffer tool, do a save project just so we don't have to do it again. Once you have your buffer, you can turn off the nitro layer and move it out of the way. We no longer need it. We're interested in this buffer because this buffer is going to help us measure the number of shootings that occur within a thousand ft of nitro properties.

I'm going to switch back to the catalog by selecting the tab on the lower right hand side of my screen here. And now I'm going to bring over the shootings layer. And I'm going to put the shootings layer right between my neighborhood layer and the pair-wise buffer. And I have two distinct sets of shootings. I have those outside the buffer, those within the buffer.

For my shootings layer, I'm going to rightclick and open up the attribute table. The attribute table again is a list of the variables in any layer. It also lists the attributes of those variables. In the shootings table, you will notice a count at the lower right hand side or excuse me, the lower left hand side of your screen. You'll also notice the move to end button. Anytime you want to know the total number of records in a data set being used in ArcGIS Pro, you can click this move to end button. It will bring you to the last record and it will tell you the count. In this case, we have it looks like 1,182 total shootings. Now, you'll notice the FID number is different. That's because a computer starts counting at zero. I can get into the whole computer science discussion of this, but unfortunately, we don't have the time. So, just trust me that this is the number you're looking at. This is the last record. This is the actual count here on the left. All right. So, keep that number in mind. Jot it down. 1,182 shootings within the buffer. Now, we want to calculate the shootings. Oh, excuse me. 1,182 shootings outside total shootings. We want to calculate the number of shootings within the buffer.

To do that, we're going to use a tool from the analysis tab called pairwise clip. Pairwise clip acts like a cookie cutter. It's going to cut out the shootings that are within our buffer for the georocessing tool. The input features are the features that we're clipping. So that's our shootings. the clip features. This is the cookie cutter part of it. That's the buffer layer we created. And the output leave because we're going to rename all of this and sort out our legend in a moment. Run the tool. And you're going to notice not a big change. You're going to notice a new shooting layer. and it's just going to be on top of our original shootings. The change is the number of shootings that occur within the buffer.

I'm going to open up the attribute table for that new layer of shootings. And again, I'm going to use the move to end button just to make sure I'm at the end of my records. And what you're going to notice is in the buffer 516 of the shootings occur within a thousand feet of Nicha buildings. As part of your discussion board question, you're going to tell me the percentage of those shootings. So, it's going to be that 516 value divided by 1,182. That will give you the percentage of shootings that occur within 1,000 ft of NICHA properties.

For formatting, it's going to be very simple. Turn off the original shootings layer. You can move it out of the way. We're interested in seeing the buffer layer, the shooting layer, and of course, our NTA layer. Rename your layers appropriately. So for NTA, I'm going to rightclick, select properties. I'm going to go with our old default neighborhood boundaries for that buffer layer. I'm going to rightclick, select properties, and I'm simply going to rename this a 1000 foot niche buffer or something similar. Again, you can start using your own naming conventions. My goal is to teach you the basics of the tools. Your goal is to start to learn to work with them so you can personalize some of your results. And then for the shootings layer, I'm going to rename this shootings within 1,000 ft of Nicha buildings.

So again, it's a simple map, but what I want you to do, particularly with the discussion board question, is compare what you see here with the hotspot map you created previously. I'm going to adjust the symbology just a little bit. My neighborhood boundaries, of course, I'm going to make a black outline. my points. I think I will go with the Mars red just so they kind of stick out but I can still see them within my buffer. Not a very visual map, but it does its job. It tells us where the shootings are in terms of the NICHA properties and the calculation you will be creating gives us an idea percentage-wise. And I'm not going to give you the value because that's part of the project. But it's a significant percentage of shootings that are occurring within a thousand ft of nitro buildings. Which then gets us into the discussion of what do we do about it? How can we reduce the levels of violence in terms of output?

Very simple. Again, I'm going to insert a new layout 8 and 1 half by 11. I will insert my map. I will insert the north arrow. Oops, I forgot to turn on my background. Don't forget to turn on the topographic map just so we have some background. I will insert my scale bar and finally my legend. And again with the legend, I'm going to rightclick, select properties, select the display tab. I'm going to add a simple black border and a simple background. Probably a good idea to save the project at this point. Um, and you might want to do one more zoom to layer. This looks like it's could be better focused as it can. So, I'll zoom in a little bit. That is our fourth map. This coincides with our third map as hopefully you will see. I want you to answer the discussion board question based on what you've created in these maps.

And this technique can be used for any type of crime. So it's not just shootings. We're working with shootings because it's a smaller data set and it's a little easier for summer session. But I want you to know you have access to all the data I use in the normal semester. So you have complaint data up there, arrest data, 911 call data. You're welcome to experiment now and start your own research. I'm going to do a project save one more time and I'll do the export. And again, the export now, these steps do not change. Share. Oh, one thing I forgot. Don't forget to rename the layout. Whoops. Right click over layout. General. So, this is our map number four. Layout. Well, that's not good spelling. There we go. Layout. And again, that's not for me. That's for you to find the map. Sometimes I forget to do it, but I've been working with the software so long, I can do some of this in my sleep. For many of you, this is new, so I try to keep the steps consistent. Now I'm ready to export the layout. And let's take a look at the completed map just to make sure. That's exactly what you should be seeing.

Now again, the interesting part is looking at what we've created here and looking at our previous heat map. There's a story to be told. All right, as always, any questions, please send me an email. Try to get these maps done so you do not fall behind in the course. Um, and happy mapping everybody. I look forward to talking to you all again real soon.