Fundamentals of Crime Mapping

GeoCoding in ArcMap

What is Geocoding?

Geocoding is the process of getting tabular data from a data source, comparing it to a geographic layer (like a shapefile) and then displaying the address matches in ArcGIS, at the location where the match was made

Step 1Create a table of addresses you want to match…

Access database

Comma Delimited File

Excel Spreadsheet

Geodatabase

File Geodatabase

Step 2Obtain a GIS Layer which has address information and fields to match to!

ArcGIS Shapefile

Step 3Create an address locator in Arc Catalog…

Right click on a folder andchoose NewAddress

Locator, oruse the ArcToolbox

Step 4Open ArcGIS and add the table…

Attribute Table to be geocoded with an address

Right click on table, and choose geocode addresses

Step 5Add the Address Locator…

Step 6Set up the Address Locator and geocoding options…

Address table Is the table with addresses to be geocoded

Street or Intersection and Zone

The fields in the table to try and match

Output Shapefile or Feature Class

Where are you saving the new geocoded file to?

Geocoding Options How accurate do you want the point to be?

Step 7Geocoding Options…

Spelling Sensitivity Do you want Indian Bend and Indian School to match?

Minimum candidate score What score does a recod match need to be to be considered a possible match?

Minimum match score At what score do we want to match or not match and place the point at that location?

Side offset How far away from the centerline do you want the point to be drawn?

End Offset How far away from an intersection do you want the point drawn?

Step 8OffSet Distances

Businesses Average 175 feet

Residential Average 55 feet

Overall Average Average 101 feet

From center of roadway to front door

Step 9Geocode those puppies…

Step 10Match interactively as needed…

Allows you to see why addresses are not matching and correct the problem

Time Consuming – one at a time

With this table there was no ZONE field

Step 11Map the geocoded data and understand it’s limitations…

Data quality can be a huge

issuewith some

data depending

on the scale at

which the data is

displayed

WHOAAA THAR!!!!

It’s time for a Break!