Getting started with attribute filtering

Introducing attribute filtering

Attribute filtering is a new concept which we have introduced as part of OS Select+Build. The filters can help you to narrow down the exact data you need from the OS National Geographic Database (NGD). If required, you can add attribute filters to individual feature types when you create a new bespoke recipe of OS NGD data using OS Select+Build. (The Downloading with OS Select+Build page has step-by-step instructions on how to create a new recipe.)

Attribute filtering is an optional step for those with advanced OS data knowledge.

You cannot apply attribute filters to feature types in existing recipes held in your OS Select+Build Recipe Library; they can only be added to new recipes during the recipe creation stage.

The following sub-sections give step-by-step instructions on how to add attribute filters to a new recipe and provide worked examples of creating both simple and nested filters.

How do I add attribute filters to a new recipe?

YouTube video showing how to add attribute filters to a new recipe in OS Select+Build.

To add attribute filters to a new recipe:

1

Log into your OS Data Hub account

2

Select Download from the main menu

3

Choose OS Select+Build from the secondary navigation menu

4

Click the Create a new recipe button, adding the relevant details to your recipe

See the Downloading with OS Select+Build page for more information on creating recipes.

5

Click the filter icon next to the feature type(s) you want to add a filter to in the theme selection tree

The Advanced Filter Options panel will slide into view from the right, you can begin to build your filter(s):

  • For a simple filter, select +Add rule.

  • For a more complex nested filter, select +Add group.

  • Once you have added all of your relevant filters, click Apply Filter.

  • Click the Create recipe button.

Worked example of creating a simple filter

In the following worked example of creating a simple filter, we will use the OS NGD Buildings Theme and select the Building Part Feature Type from the Building Features Collection. Our aim is to build a filter to select buildings where education is recorded as the land use.

1

Log into your OS Data Hub account

2

Select Download from the main menu

3

Choose OS Select+Build from the secondary navigation menu

4

Click the Create a new recipe button

5

Click on the arrow to the right of Buildings within the theme selection tree to see the collections available within the theme, then click on the arrow to the right of Buildings Features to see the feature types available within that collection

6

Click on the check box next to Building Part to select that feature type

OS Data Hub screenshot, showing part of the theme selection tree in OS Select+Build. A filter icon is visible against the Building Part Feature Type. The Building Part Feature Type has been selected.
Screenshot showing a filter icon against the selected feature type in the theme selection tree in OS Select+Build
7

Click on the filter icon to the right of Building Part

The Advanced Filter Options panel will slide into view from the right, where you can begin to build your filter(s).

8

Build a filter where the OS Land Use Tier A attribute is set to Education.

In the Advanced Filter Options panel, click + Add rule, then select OSLandUseTierA from the first drop-down.

OS Data Hub screenshot, showing the Advanced filter options panel in OS Select+Build. In the rule, OSLandUseTierA is selected in the first drop-down.
Screenshot of adding a rule in the Advanced Filter Options panel in OS Select+Build.

Leave the operator in the second drop-down as: = (i.e. the equal sign), then select Education from the third drop-down.

OS Data Hub screenshot, showing the Advanced filter options panel in OS Select+Build. In the rule, OSLandUseTierA is selected in the first drop-down, the equal sign is selected in the second drop-down, and Education is selected in the third drop-down.
Screenshot of adding a rule in the Advanced Filter Options panel in OS Select+Build.
  • Click Apply filter.

9

Click the Create recipe button

Worked example of creating a nested filter

What if, in addition to the simple filter above (returning results for buildings with a land use of education), we want those results to show only buildings over 15 metres in height? What if you also wanted to add an additional filter to show buildings with a land use of rail? To achieve this, you could create a nested filter using the + Add group option.

1

Follow the steps outlined above for creating a simple filter for Building Part until you reach the Advanced Filter Options panel step

2

In the Advanced Filter Options panel, click + Add group, then select OSLandUseTierA from the first drop-down

Leave the operator in the second drop-down as: = (i.e. the equal sign), then select Education from the third drop-down.

3

Click + Add rule to add a second rule below the OSLandUseTierA rule

4

In the second rule, select relativeHeightMaximum from the first drop-down, set the operator in the second drop-down as > (i.e. the more than sign), and type 15 in the input box

5

Before continuing, select whether you would like the rules within the group to have an And or an Or condition

In this case, you should select And from the And / Or selector.

OS Data Hub screenshot, showing the Advanced filter options panel in OS Select+Build. Two rules have been created in the first group.
Screenshot of creating a nested filer in the Advanced Filter Options panel in OS Select+Build.

Next, click + Add group.

OS Data Hub screenshot, showing the Advanced filter options panel in OS Select+Build. Two rules have been created in the first group, and the +Add group button has been clicked and the application has drawn an extra box.
Screenshot of creating a nested filter in the Advanced Filter Options panel in OS Select+Build.

The application has drawn an extra box for you. Whatever rules are contained inside this box will be evaluated together, before combining with any rules outside the box.

  • Before continuing, select whether you would like the rule in the second group to have an And or an Or condition. In this case, you should select Or from the And / Or selector.

  • In the rule in the extra box, select OSLandUseTierA from the first drop-down, leave the operator as = (i.e. the equal sign) in the second drop-down, and select Transport: Rail from the third drop-down.

  • Click Apply filter.

6

Click the Create recipe button.

OS Data Hub screenshot, showing an example of a nested filter with an And condition and an Or condition applied in the Advanced filter options panel in OS Select+Build.
Screenshot of creating a nested filter with And and Or conditions in the Advanced Filter Options panel in OS Select+Build.

How do I check if filters are used in an existing recipe?

To check what filters have been applied to feature types in an existing recipe:

1

Log into your OS Data Hub account

2

Select Download from the main menu

3

Choose OS Select+Build from the secondary navigation menu

4

In your OS NGD Select+Build Recipe Library, scroll or search for the recipe.

5

Click on the name of the recipe you would like to find out more about

You are now within the Recipe details screen, where you can view detailed information about the recipe, including the recipe's name, the date it was created, etc. If filters have been applied to the recipe, a filter icon (i.e. a black funnel symbol) will appear under the recipe name alongside text stating: 'Filters have been applied to this recipe'.

  • Click View all filters to view all of the filters that have been applied to feature types in the recipe.

In the example recipe below, you can see that there is a filter icon (i.e. the black funnel symbol) against the Building Part Feature Type; therefore, this feature type has filters applied to it.

Screenshot of the OS Data Hub, showing the OS Select+Build recipe details screen. This screen shows in-depth information about an example recipe, including the recipe name, a description of the recipe, the filters used, the creation date, its author, and the OS NGD themes, collections and feature types present within it.
Screenshot of the OS Select+Build Recipe details screen, which shows in-depth information about the contents of an example recipe.

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