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In this guide, you will learn about different options for geocoding addresses, also known as address locating. Although there are other types of geocoding using geographies like census tracks or even zip codes, this page will focus on address geocoding. Address geocoding is the process of turning text addresses into geographic information for use in GIS software or mapping applications.
Warning: Some of the methods discussed in this guide are available only to UWM affiliates with an epanther ID.
Warning: Some of the methods discussed in this guide consumes credits on your ArcGIS Online account.
Geocoding translates a text description of a location into spatial data. An example is mapping a list of customers by their zip code. The zip code allows us to assign each customer to a geographic area and view our customers on a map.
If you're trying to find your way to a place you have never visited before, you might enter the address into Google Maps. Google Maps will quickly use address geocoding to translate your query into a point on the map. Behind the scenes, the software is comparing the address you supplied to a list of addresses generated by querying their vast database of street and address data.
An address locator is a software object that actually does the translating from text to spatial data. In order to do its job, it needs reference data. Most often, this will be in the form of street network data with address features. A very common type of address locating in the United States is called dual range where each side of the street has a range of addresses such as 2400-2498 (even) on the left side and 2401-2499 (odd) on the right side. The address locator will take a given address and compare it to these ranges and estimate where on the block the address is likely to fall and which side of the street it is on.
Some reference data may be even more detailed and give a specific location for any valid address in the given area. This could take the form of an address points dataset or a parcel dataset. Many address locators use multiple datasets to decrease mismatches and errors.
You can read much more about address locating and other types of geocoding on their respective platforms:
UWM GIS users have three primary options for Address Geocoding:
The excel file below is a sample file containing information about dog licenses in Milwaukee County from 2011. The examples below will make reference to the file, but a step by step tutorial is not provided here. Most GIS textbooks include a lab about address geocoding--students are encouraged to use that for guidance. There are about 20,000 records in the table representing 20,000 dog licenses.
Summary: For small jobs (< 500 addresses), consumes credits
Geocoding can be performed in ArcGIS Online, ArcGIS Desktop, or ArcGIS Pro by selecting the ESRI World Geocoding Service as an address locator. For small jobs, this is a convienient and effective way to geocode addresses. For large batch jobs or workflows that require frequent geocoding operations, this method will quickly consume a user's credits on their UWM ArcGIS account. This option is often the default and many users mistakenly consume all of their available ArcGIS Online credits by attempting to use this method.
Credits are consumed at a rate of 40 credits per 1000 addresses. Geocoding the entire sample data of dog licenses (N > 20,000) will consume more than 800 credits. UWM users are usually assigned 100 credits, this means that only a portion of your data will be processed. As you will see below, there are other ways to complete these tasks without needing to request more credits.
To use the ESRI World Geocoder in ArcGIS Desktop (ArcMap) or ArcGIS Pro, import the tabular data to be geocoded and when asked to select an input locator choose ESRI World Geocoder. You can also use the ESRI World Geocoder in web maps and web applications in ArcGIS Online and ESRI Web AppBuilder by using the search widget.
Say you're making a web application and you want the user to provide an address and then see that location appear on the map with relevant data. You application needs to geocode that data, and that usually requires a geocoding service.
There are many geocoding services available, and if you're building web applications in ESRI Web AppBuilder at UWM, you can use the search widget without the worry of consuming all of your credits. But if you plan to use address locating in a custom application or you don't have an ArcGIS License, you need to find (or host) a service or API. A few are listed below for reference.
Warning: Carefully read documentation when including geocode functionality in a web mapping application. Check if your use of the ESRI World Geocoding Service consumes credits on your ArcGIS Online account. Many APIs and services have pricing models that allow for free usage up to a limit and then require a paid subscription.
Summary: For large jobs, great for beginners but more difficult to customize
About: Good news! People create and share address locators that you can download and use in desktop GIS to batch geocode addresses.
Do you want to geocode addresses from Milwaukee County? The AGSL maintains an address locator package that you can download and use in ArcMap or ArcGIS Pro. Before using this locator, you must format your data so that the street address is in one field. Match accuracy will be increased if your data also has zip code information in a separate field, but it is not required.
Is in development
Summary: For large jobs, great for advanced jobs with complex data
If you are having trouble finding the data you are looking for, the AGS Library may be able to help.
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