Turning addresses into points on the map (Geocoding)

Do you need to turn your list of addresses into points on the map?  Here, we’ll show you how to use the MAR Geocoder and how it can create map coordinates using street address information from a MS Excel spreadsheet.

This How-to will teach you how to:

• How to install and utilize the MAR Geocoder
• How to prepare your data for the MAR Geocoder
• Show address points on the map using ArcGIS
  
  

About Geocoding

What is Geocoding? Geocoding is the process of assigning a location in the form of geographic coordinates (lat/long) to geographic data. Instead of manually looking at an address and placing a point on a map, tools have been created to automatically place the point(s) on the map, usually relative to a GIS street centerline.  The process is done by comparing the descriptive geographic data to known geographic locations such as addresses, blocks, intersections or place names. 

Step-by-step guide

1. Download and install the MAR Geocoder:   
   1. Note:  User must have administrative privileges to install.   
   2. Visit OCTO's apps page:  http://octo.in.dc.gov/page/gis-and-bi-apps-and-services
   3. In the 'Desktop' section, click on 'MAR Geocoder'.
   4. Click on the link to download the MAR Geocoder.
   5. Right-click on the downloaded file and unzip.
   6. Double-click on the MARGeocoderBootstrapper.exe file to install.
2. Data Preparation 
   1. The MAR Geocoder requires the data to be in either Access or Excel format (Microsoft Access 2003, 2007 and 2010 table or Excel spreadsheet 2003 and 2007).    
   2. All addresses for geocoding will need to be entered in one column. 
   3. Name the column accordingly (ex. “Address”, “Location”) and avoid using spaces, special characters, and SQL keywords (SQL  keywords ‐ http://msdn.microsoft.com/en‐us/en%E2%80%90us/library/aa238507) 
   4. Follow the MAR Addressing Standards for correct address format (http://dcatlas.dcgis.dc.gov/mar/)
3. Open the MAR Geocoder
   1. Double‐click the MAR Geocoder icon on your desktop (hint: DC flag icon) 
   2. Select your Access Database (for database) or Excel Spreadsheet (for workbook) 
   3. Based on your selection browse (click Browse button) for the Access database or Excel Spreadsheet workbook 
   4. Again based on your selection click the dropdown arrow to select the Table (for Access Database) or Worksheet (for Excel Spreadsheet) 
   5. Under the Input Fields panel click the dropdown arrow to choose the field that corresponds to the Addresses. You can set the Minimum Match score (Batch only) or accept the default. Zip code is optional
4. Click Batch for batch geocoding
   1. The program will begin processing your address records.  Depending on the amount of records, this may take several minutes.
5. Examine the results
   1. Once complete, open your Access Database or Excel Spreadsheet. 
   2. Notice the added tables (MAR_ADDRESS, MAR_AID, MAR_BLOCK, MAR_INTERSECTION and MAR_PLACE_NAME). 
   3. Open the your original table. There are additional fields (about 13). 
   4.  Among these additional fields there should be a pair called MAR_LONGITUDE and MAR_LATITUDE. These XY coordinates may be used to create a GIS point layer in ArcMap or ArcGIS Online.

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