You may have a record level data file, which contains a row for every sale or every customer or every postcode. In order to plot the data in this file the system needs to convert your data to either postcode area, a district or a sector. This conversion to a higher level is known as aggregation and will create a new summary dataset for you at the new level. If you convert to postcode area, then all the values on the rows with a postcode within an area will be automatically added up.
To get to this page you can either:
The system will create a new dataset at the level you have chosen.
Record level rows will be grouped together based on the level you have selected. The values in this new dataset will be automatically calculated by adding up all record level values for the rows in each group.
If you chose 'Other' then you can enter what each row represents, which will be used as the name for the row count column in the new dataset.
Enter a name in the 'Dataset Name' text field.
Make sure this is a unique name. If you have already used this name for another dataset then you will be told to enter a different one.
Any numeric fields will automatically be added to the new dataset as a Sum (of all the rows in the group). You can change the name of these columns.
In the example above 3 summary fields have been added automatically.
'Sales' and 'Revenue' are added because they are a total of the sales and revenue columns (in the record level source file).
If you are happy with these columns then click 'Next' to choose which field to plot.
If you wish to add another summary column then complete the next step before you click 'Next'.
(This is optional)
Choose the source column from the drop down. In the example above 'sales' is the source column.
Choose the calculation such as SUM or Average. In the example 'Avg (Mean)' is chosen.
Enter a name for the new column. In the example above it is 'Sales per Customer'.
The 'Mean' calculation is the Sum (of the column for all the rows in the group) divided by the number of rows in the group.
In the example above 'Mean Sales' would be the average number of sales per customer in each area. Therefore we named it 'Sales per Customer'.
Click 'Add', which will add the field to the table above.
Click 'Next' when you have finished adding custom fields.
You are now on the last page of the map wizard.
Click on the field you wish to plot.
This can be changed or completely customised once on the map screen.