The Filter by column value analysis enables you to filter a map layer by a selected column from your dataset. If you are familiar with using SQL, this is similar to a typical WHERE operation on a database. You can select the column to be filtered and define limits, or a range of values (depending on your data).
For this guide, we will use maps created from other guides so that you can practice filtering layers by column values. Depending on the data of the column selected (string or numerical), different filter options can be applied.
Apply the Filter by column value analysis as the next chain in the workflow for the Austin Fire Stations map. The map layer contains several types of identified data; such as fire stations, police stations, and hospitals. Our goal is to show only the fire stations for your layer.
Create the map from this guide, about georeferencing street addresses. The map contains Austin Fire Stations as the first map layer and fragmented data as the second map layer.
From the fragmented data layer, click the ANALYSIS tab.
+ from Your worflow, to add a second analysis to the chain.
Select Filter by column value and apply the following options:
The map layer refreshes and shows only the fire stations for your map layer.
If you switch to the Data View of your map layer, only the rows that contain
In this section, let's apply the Filter by column value analysis as the next chain in the workflow for the Thanksgiving Google Flight Searches map. The map layer contains the
length output column, that was created as a result of the Connect with lines analysis. This column displays the distance between the airports from the origin cities to the destination. Our goal is to show only the flights less than specified distance away from the origin.
Create the map from this guide, about origin flights from Miami during Thanksgiving. The map contains Flight Destinations as the first map layer, Origin City as the second map layer (with the Connect with lines analysis applied), and a copy of the original source of Origin City as the third map layer.
In order to avoid any confusion between layers, rename the third map layer (layer C) to "Source".
Click on the Origin City map layer.
Click the ANALYSIS tab.
+ from Your workflow, to add a second analysis to the chain.
Select Filter by column value, and apply the following options:
For FILTER, select is less than as the operation.
For VALUE, type in the
1621 as the maximum value. This indicates the distance in kilometers.
The map layer refreshes and displays only the flights that are less than 1621 kilometers from Miami.
If you switch to the Data View of your map layer, only the rows that contain the matching values appear.
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