Lab 6: Geocoding
You have received a dBase file that contains the address list of over 500
homes in your neighborhood that have had reports of lead poisoning in
infants and toddlers over the past 10 years.
You have been asked to locate these addresses on a map within your
study area.
How will you find these locations & display on a map using MapInfo?
In this lesson, you will learn how to geocode using two methods of
address matching: by interpolation & center of polygon
You will also learn how to increase your match rate and display the
geocoded locations on a map.
The following slides step through the geocoding process
using the address method (interpolation) in MapInfo
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Open the target db (table to geocode)
Determine the key field to use to geocode
Run the table of addresses through an address standardizer (if available)
Determine if a field such as such as zip code or city exists so that you use the refine
search option with a polygon file
5. Create a new field to store the geocode result code (code gives idea why matches
did not occur)
Reference db- Street Centerline
Determine the reference db to use.
Determine the key field that will be used
as the match in the reference table.
Determine the field name of the polygon
file that contains the zip or city
In MapInfo, Select Table> Geocode
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3 Table to use to locate address
4 Field used to match address from #2
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1 Table to geocode
2 Field containing address in table to geocode
5 Optional refine by using zipcode table
6 Field containing the zipcode in refine table
6a Field with zipcode in table to geocode
7 Select Options button
8 Place result code in this field
9 The offset distance from street when using interpolation
10 The distance in percent from end of street to start
placing points
11 Select OK to the options selected
12 Select Mode- Automatic on 1st pass
13 Select symbol icon to display geocoded point
14 Select OK to begin geocoding your data
Geocoded points result using address matching to street centerline
Interpolation Method
Result code values
Any negative value means that
the record did not geocode
The code may give you an idea of
the error.
Geocoding using the polygon method
Polygon method finds exact match between
the 2 address fields (columns) of the 2 tables.
It must be a perfect match to locate the point.
The result is a geocoded point symbol in
The centroid (weighted center) of the parcel
polygon.
Geocoding results using both Interpolation and Polygon Methods
You are now ready to begin MapInfo Exercise- Lab 6
Geocoding. The main objectives are:
• To open a dBase attribute table to geocode
• To geocode using both methods:
interpolation along a street centerline
by Polygon centroid using matched address fields
• Begin exercise- lab 6