This document explains the method to geocode using street address data in NT Visualiser

Geocoding and Labelling using street address information

NT Visualiser is available across NTG and is an application which marries the functionality and imagery found in Google Earth with spatial information and imagery managed and owned by NTG. For more information (including installation and log in) go to NT Visualiser - Information and Installation Manual

Prior to Geocoding, it is important that you collect accurate, current and complete street address information. For the purpose of this demonstration, a text file called "AddressText.txt" has been created (see NT Visualiser - Geocoding street addresses example) and will be used. The text file has delibrately included misspellings, missing data and incomplete street addresses to demonstrate what happens when incomplete or inaccurate data is used.


The Data Import Wizard

appears (Figure 1)


Figure 1 - The Data Import Wizard

As we are opening a text file, the following parameters need to be se

For Field Type - Tick "Delimited"
For Delimited - Tick "Treat consecutive delimiters as one"
For Delimited - Tick "Tab"

Looking at the Preview of the data, it is evident that already, with the omission of a street type, all the data has been moved one place to the right. This will cause problems later on (as we will see)

The Select Latitude/Longitude Field Window appears(Figure 2)

Figure 2 - Select Latitude/Longitude Field Window

In this window,

Tick "This dataset does not contain latitiude/longitude information, but street addresses

 Figure 3 - Definition of Street Addresses Window

The Specify Field Types (optional) window appears ( Figure 4). All values can remain as is. Click Back

Figure 4 - Specify Field Type (optional) Window

If all street number, street name, street type and suburb values are complete and correct, the following error should not appear

Although the error does not tell you what exactly is the problem (or its cause), the street name "Chewing" is spelt incorrectly. The correct spelling is "Chewings". To fix, cancel this message ( click the red X box), open the text file, correct the mistake, save and then repeat all steps outlined before this point.

The following message appears if all the above configuration has been completed correctly. Click Yes to apply a style template

The Style Template Settings

Window (Figure 5) appears next. Here, you can configure the colour and allocate a desired icon for placemarkers

We would like to label the street number for each parcel that we are geocoding. To enable labelling set the value of "Set name field" to street_no

(or the column which has the information you wish to be labelled)

Figure 5 - The Style Template Settings Window

Review the Color and Icon tabs and configure these settings as desired. An Icon represents a placemarker. Each geocoded address will be represented by a placemarker at or near the parcel boundaries or at the centre of the parcel.

Once saved, NT Visualiser will refresh and

Figure 6 shows the result of importing and geocoding  "AddressText.txt" into NT Visualiser.

Figure 6 - Results of importing geocoding street address and labelling street numbers

The Addresses defined in the text file are geocoded and matched to address data provided through a service from Google. The currency of this data provided by Google is uncertain. There may be some differences in data currency between addresses provided by Google and those found in Government web mapping systems or ILIS ( the later being more current).

Geocoding - Things to look out for

From the example above, four addresses geocoded correctly (7,8,9 and 5). Three did not

The following table shows the data in the full_address column of AddressText.txt ( data used to Geocode) and whether it Geocoded or not. Reasons have been provided to highlight possible erorrs that can cause Geocoding to not work

7 Kirk Place GillenYes - Geocoded correctly and represents the correct parcel
8 Nicker Crescent GillenYes - Geocoded correctly and represents the correct parcel
9 Ballingall Street The GapYes - Geocoded correctly and represents the correct parcel
5 GAP ROAD THE GAPYes - Geocoded correctly and represents the correct parcel
9 Chewing Street East SideNo - "Chewing" misspelt so did not Geocode
43 Cavenagh Street East SideYes -  43 does not exist so it has geocoded to the road centreline
40 Cavenagh East SideNo - missing street type. Did not import at all.
 5/14 Smith Street Alice Springs No - unit numbers cannot be Geocoded. Omit

This table highlights the importance of ensuring that when you are collecting street address data, you must ensure that the street numbers exist, the street name and type are spelt correctly and exist and the suburb is actually a registered place name