# 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 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 [managing OS Select+Build recipes page](https://docs.os.uk/osngd/getting-started/downloading-with-os-select+build/getting-started-with-recipes/managing-os-select+build-recipes) has step-by-step instructions on how to create a new recipe. You can also add, edit or remove attribute filters to / in / from feature types in an existing recipe of OS NGD data. Attribute filtering is an optional step for those with advanced OS data knowledge. {% hint style="success" %} You can: * Add attribute filters to feature types in a new recipe * Add, edit or remove attribute filters to / in / from feature types in an existing recipe {% endhint %} The following sub-sections cover:


Adding filters to a new recipe	#how-do-i-add-attribute-filters-to-a-new-recipe
Adding filters to an existing recipe	#how-do-i-add-attribute-filters-to-an-existing-recipe
Creating a simple filter (worked example)	#worked-example-of-creating-a-simple-filter
Creating a more complex nested filter (worked example)	#worked-example-of-creating-a-nested-filter
Checking if filters are used in an existing recipe	#how-do-i-check-if-filters-are-used-in-an-existing-recipe

## :arrows\_clockwise: How do I add attribute filters to a new recipe? {% embed url="" %} YouTube video showing how to create a recipe using OS Select+Build, add filters to the recipe, then create a data package to receive your OS NGD data. (Attribute filtering is discussed around four minutes into the video.) {% endembed %} To add attribute filters to a new recipe: {% stepper %} {% step %} #### Log into your [OS Data Hub](https://osdatahub.os.uk/) account Click *Login* on the OS Data Hub menu bar to log into your account.

{% endstep %} {% step %} #### Navigate to the OS Data Hub workspace Select *Data* from the menu bar to view your workspace. {% endstep %} {% step %} #### Navigate to the OS Select+Build Recipe Library Choose *Downloads* > *OS Select+Build Recipe Library* from the left hand side secondary navigation menu. You will then be taken to your organisation's OS Select+Build Recipe Library.

Screenshot of the OS Select+Build Recipe Library screen in the OS Data Hub.

{% endstep %} {% step %} #### Create a recipe Click the *Create a new recipe* button, adding the relevant details to your recipe. See the [Managing OS Select+Build recipes page](https://docs.os.uk/osngd/getting-started/downloading-with-os-select+build/managing-os-select+build-recipes#how-do-i-create-a-new-recipe) for more information on creating recipes. {% endstep %} {% step %} #### Add filters to feature types in your recipe 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 then slide into view from the right and you can begin to build your filter(s): * For a [simple filter](#worked-example-of-creating-a-simple-filter), select *+Add rule.* * For a more complex [nested filter](#worked-example-of-creating-a-nested-filter), select *+Add group.* * Once you have added all of your relevant filters, click *Apply Filter*. {% endstep %} {% step %} #### Finish creating the recipe Click the *Create recipe* button. Your new recipe with filters will now instantly be available in your OS Select+Build Recipe Library. {% endstep %} {% endstepper %} ## How do I add attribute filters to an existing recipe? To add attribute filters to an existing recipe: {% stepper %} {% step %} #### Log into your [OS Data Hub](https://osdatahub.os.uk/) account Click *Login* on the OS Data Hub menu bar to log into your account.

{% endstep %} {% step %} #### Find the recipe you want to edit In your OS NGD Select+Build Recipe Library, scroll or search for the recipe you would like to edit. Once you've found the recipe, click on its name; you'll be taken to the Recipe details screen. {% endstep %} {% step %} #### Edit the recipe In the Recipe details screen, click on the *Recipe actions* dropdown and select *Edit recipe*.

Screenshot of the OS Select+Build Recipe details screen with the Recipe actions dropdown open, showing where you can share, edit or delete a recipe.

You'll now be able to add filters (see **Step 6**) or remove filters (see **Step 7**) from feature types in the recipe. {% endstep %} {% step %} #### Add a filter to a feature type * Click the *filter icon*

next to the feature type you want to add a filter to in the selection tree for the recipe. The Advanced Filter Options panel will then slide into view from the right and you can begin to build your filter(s): * For a [simple filter](#worked-example-of-creating-a-simple-filter), select *+Add rule.* * For a more complex [nested filter](#worked-example-of-creating-a-nested-filter), select *+Add group.* * Once you have added all of your relevant filters, click *Apply Filter*.

Screenshot of the OS Select+Build Recipe Edit recipe screen with the Advanced Filter Options panel showing. — Screenshot of the OS Select+Build Recipe Edit recipe screen with the Advanced Filter Options panel showing, where you can add a filter to a recipe.

* Select *Save changes*. * Add a description of the change you have made, then select *Save changes*. {% endstep %} {% step %} #### Remove a filter from a feature type * Click the *Edit filter icon* Filter icon in OS Select+Build

next to the feature type you want to remove a filter from in the selection tree for the recipe. * When the Advanced Filter Options panel slides into view from the right, select *Clear all filters*.

Screenshot of the OS Select+Build Recipe Edit recipe screen with the Advanced Filter Options panel showing. There is one filter applied to the Building Part Feature Type.

* Select *Save changes*. * Add a description of the change you have made, then select *Save changes*. {% endstep %} {% endstepper %} ## 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. {% stepper %} {% step %} #### Log into your [OS Data Hub](https://osdatahub.os.uk/) account Click *Login* on the OS Data Hub menu bar to log into your account.

{% endstep %} {% step %} #### Create a new recipe Click the *Create a new recipe* button. See the [Managing OS Select+Build recipes page](https://docs.os.uk/osngd/getting-started/downloading-with-os-select+build/managing-os-select+build-recipes#how-do-i-create-a-new-recipe) for more information on creating recipes. {% endstep %} {% step %} #### Add details to the recipe * Give your recipe a descriptive name. * Add a detailed description for your recipe * Select your OS NGD data by choosing the themes, collections and feature types you want to include in your recipe. For this worked example: * 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. * 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

{% endstep %} {% step %} #### Add a filter to the Building Part Feature Type where the *OS Land Use Tier A attribute* is set to *Education* * 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): * 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.

* Click the *Apply filter* button. {% endstep %} {% step %} #### Finish creating the recipe Click the *Create recipe* button. Your new recipe will now instantly be available in your OS Select+Build Recipe Library. {% endstep %} {% endstepper %} {% hint style="success" %} Your filter will return buildings where education (Education) is recorded as the land use (OS Land Use Tier A attribute). {% endhint %} ## 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 15metres 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. {% stepper %} {% step %} #### Follow the steps outlined above for creating a simple filter for Building Part until you reach the Advanced Filter Options panel step (Step 6). {% endstep %} {% step %} #### Add a simple filter to the Building Part Feature Type * 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. {% endstep %} {% step %} #### Add a nested filter to the Building Part Feature Type * Click *+ Add rule* to add a second rule below the OSLandUseTierA rule. * 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. * 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*.

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.

{% endstep %} {% step %} #### Finish creating the recipe Click the *Create recipe* button. Your new recipe will now instantly be available in your OS Select+Build Recipe Library. {% endstep %} {% endstepper %} {% hint style="success" %} Your filter will return results for buildings (Building Part) that have either an education (Education) land use if that building is over 15 metres high or a railway land use (Transport:Rail). {% endhint %} ## 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: {% stepper %} {% step %} #### Log into your [OS Data Hub](https://osdatahub.os.uk/) account Click *Login* on the OS Data Hub menu bar to log into your account.

{% endstep %} {% step %} #### Find the recipe you want to check for filter presence on In your OS NGD Select+Build Recipe Library, scroll or search for the recipe you would like to edit. Once you've found the recipe, click on its name; you'll be taken to the Recipe details screen. {% endstep %} {% step %} #### Check for filter presence 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 Filter icon in OS Select+Build

(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 Filter icon in OS Select+Build

(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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