Point Join

Introduction

The Point Join tool allows you to associate a point dataset with all of the attributes of a polygon dataset that ‘overlays’ it. In this sense, the point join tool is similar to the ‘identify’ tool found in a number of desktop GIS platforms.

Inputs

In this example we will take a point file – Gambling venues across the Melbourne SA4, and join them to (or ‘identify them by’) the SA2 that they fall into, together with some demographic data associated with that SA2. To do this:

  • Select Melbourne – Inner SA4 as your area
  • Select the following datasets:
    • SA2-based B01 Selected Person Characteristics as at 2011-08-11 with all variables checked (and 2011 as your time filter)
    • Gaming Venues 2013 for Victoria with all variables checked
  • Spatialise your SA2-based B01 Selected Person Characteristics as at 2011-08-11 dataset. The Point Join tool will not work with a polygon dataset that has not been spatialised.

Once you have loaded your data, open the Point Join tool (Tools → Spatial Data Manipulation → Point Join) and enter your parameters as shown below. You need to specify the point file that you want to join the data too, and the spatialised polygon file that will be joined. You can choose whether you will only include points in the output file that have a polygon boundary that they fall into (and thus, some variables that can be joined to them).

Once you have entered the parameters click Add and Run

pointjoininputs

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Outputs

If you open the resultant dataset, named Output: sphspatial1-join XXX, you will see that it is a point dataset, but each point now contains the values for all of the attributes of the polygon that you joined it to. If you right click the dataset and click Display on Map, and then hover over the resultant points, you will see the dataset with all of the variables (shown below)

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