Join Adam Wilbert for an in-depth discussion in this video Geocoding addresses, part of ArcGIS Essential Training.
- The most common way that we find places in the real world is through their street address. Our maps, however, use a grid system of coordinate pairs, such as latitude and longitude to locate points on the surface of the earth. For instance, on the tools toolbar, I've got this button here called "XY". If I click on it, I can type in a longitude and latitude values to see where that is on the map. For longitude, I'm going to type in -122, and for latitude, I'm going to type in 48. When I press enter, the map gets centered on the screen and its position flashes to indicate where that is. In this case, we're looking at 122 degrees west longitude, and 48 degrees north latitude.
This is an area in northwest Washington state, near where I live. Now, what we can do is zoom into that position here, by clicking on this "Zoom To" option. That'll zoom in my map and reflash its position again. We also have options here to pan around. I can pan to that location if I wasn't there, or I can flash its position, so it'll blink it on the screen. I can add a point there, I can add a labeled point, or I can add a callout here. Let's go ahead an select these options, and I'm going to select these features by choosing this option here, the Select Elements. I'll click on each one and delete them. Now this is the coordinate pair system that ArcMap is using to locate features in the map.
The process of translating from a written address to a coordinate pair, indicating a single point on the map, is called geocoding. In order to geocode an address, the computer first needs to parse the text string, in order to understand it, and then look up the correct coordinates in a massive database. Now, it's unlikely that you have this kind of system on your local machine, but data providers such as Esri do, and we can tap into their geocoding service to help us out. We can do that by first turning on the geocoding toolbar. I'm going to close out the Go To XY dialogue here, and go up to Customize>Toolbars, and then choose the Geocoding toolbar here.
The Geocoding toolbar loads up, and it functions just like you would expect from using Google Maps or Bing Maps, or some other such service. On the left we have an option to choose our address locator. We can either use Esri's World of Geocode Service, which is a product of ArcGIS online, or we can use the Military Grid Reference System. Let's go ahead and leave it with the World Geocode Service, and over here where it says, "Type in an address", we can type in a location that we are interested in finding. For instance, I'm just going to type in, "Washington Dc." and press Enter. When I do, it tells me that it found Washington D.C., District of Columbia, United States.
If I right-click on it, I get some additional options. For instance, I can zoom to that particular location. When I do that, the map recenters on Washington D.C. I can right-click and flash its location, and it blinks on the screen, or I can right-click and pan to it. I can also create a bookmark, and I can add the same point, label point, and callouts that we saw earlier. I also have options to add this into My Places, to go straight into the My Places Manager, or to do some routing or network analysis tasks. Let's go ahead and find another location. Instead of Washington D.C., I'm going to type in "France".
When I press enter, ArcMap tell me that it found France, so that's good. I'll right-click and say Zoom To, and it should zoom me right into France. Now, if I type in "Paris", press Enter, it will find that location and it will flash it on the screen, at which point I can right-click and zoom into it, as well. So we can also type in full addresses here. So what I want to do is click on where it says, "Paris", and type in the address, "6410 Via Real, Carpinteria, California." When I press Enter, ArcGIS geocodes this particular address and finds it. I'll right-click on it, and zoom to this particular location.
This is the corporate headquarters for lynda.com. Let's take a look at one more address. I'll highlight this and type in, "380 New York St., Redlands, California." Once again I'll press Enter, it tells me that it finds that location. I can right-click and zoom to it. 380 New York St, Redlands California is the corporate headquarters for Esri. Now all of these have been examples of something called forward geocoding. Forward geocoding is where we translate a human readable address into the coordinate pair for the map. We can also do something called reverse geocoding. This is where we provide the point, and ArcGIS will tell us what the address is there.
So let's go ahead and take a look at this Redlands, California area. I'm going to zoom out just a little bit. Just zoom out on the map a few clicks, and I'm going to pan over here to the left. Now, let's say I wanted to find the address of this particular building here. In order to do what's called a reverse geocode, I'll click on this icon here, the Address Inspector, and now, if I hover my mouse over and click and hold my left mouse button, I'll get a little pop-out window that indicated where the address is. In this case, this particular building, is at 301 Tennessee St. in Redlands, California.
I can go ahead an click on other buildings to see their address. This one is at 300 Kansas St. Now, notice that while I am holding the left mouse button down and this pop-up window is up, I get some text up on the bottom status bar. It says, "Keys: K=Copy, P=Add Point, "L=Add Label Point, and O=Add Callout." These correspond to the options that we saw when we right-clicked on this menu here. We can choose to Add a Point, Add a Label Point, or Add a Callout. So we can add those features here, using the Address Geocoder. If I click on this building here, I'll left-click and hold, and now press "o" while I'm holding down the left mouse button, that will add in the callout to this particular address, and we can see that it's 278 Tennessee St. in Redlands.
Now, at the very beginning, we saw that we had multiple geocoding services available. I can change this option here, from the World Geocode Service to the Military Grid Reference System. This is a global grid system developed by NATO. If I click on here, I can see the Military Grid reference of each of these positions, as well. So you can see that this particular building is MGRS coordinate 1-1-S-M-T-8-1-1-8-5-6-8-3-9-4. So that's how we can leverage some of the power of the ArcGIS online geocoding service. Geocoding is a resource intensive process, but thankfully, Esri allows us to offload those processes onto their servers, and fetch just the points that we need, without all of the overhead of running our own world-wide geocoding database.
So go ahead and use the service to try locating addresses in your own neighborhood.
- Getting to know the ArcMap interface
- Geocoding addresses
- Measuring distances
- Adding and importing data
- Labeling and adding graphs
- Editing layer properties
- Seeing multiple views
- Making selections
- Exploring geospatial data with ArcCatalog
- Working with vector and raster data
- Styling the map
- Adding your own data
- Using the ModelBuilder
- Adding a legend and annotations