Creating a multi-layer map begins the same way as creating any other map on Socrata - going to a dataset with a valid geospatial column, clicking Visualize, and selecting the Map option.
Doing so will show all of the options to configure a map layer that existed previously. With multi-layer maps enabled, users will now see a new option to go to the Layer List, which allows for the creation and configuration of additional layers on a single map visualization.
The Layer List
From the Layer List, users can create additional layers to add to their map, choose to configure existing layers and control how layers appear on the final map.
From the Layer List, users can:
- Select Add Layer, which will prompt the user to select an additional dataset and then configure their additional layer.
- Change the order in which layers will appear on the map (eg, which will appear the “highest” or “lowest”) through the selection of up and down arrows on each layer
- Choose to show or hide each layer, to hide previously configured layers when working on adding a new one
After adding a second layer to the map, the Layer Toggle will automatically appear on the map, which allows consumers to toggle layers on or off as they explore the visualization. This toggle can be disabled in Map Settings > Map Controls.
To add filters to your map, navigate back to the layer configuration for the Primary layer of the map and click the Add Filters button at the top of the page.
At any time, users can access the settings for the base map and other map configurations by clicking the gear icon on the left side of the page.
The Map Setting section contains several tabs with configuration options, including:
- General: Add a title and description to your map, which will appear in the Asset Inventory and when a user navigates to the visualization.
- Basemap: Select a preferred basemap for the map. Alternative options like Streets, Satelite, Dark and Light themed maps are available in this section.
- Map Controls: Selects the controls that will be available to a map consumer. Options include showing or hiding the search bar, showing or hiding the “Locate Me” button, showing or hiding the zoom and pan buttons, and showing or hiding the layer toggle.
- Search Boundary: The service that allows users to search for a human-readable address on the map references addresses across the globe. To ensure that users are only directed to meaningful search results, we support the ability to limit search results to a predefined area. To set a search boundary, simply hold “shift,” then click and drag on the map.
- Clusters: To improve performance and help users meaningfully interpret large amounts of point data, Socrata uses a methodology called clustering for grouping nearby points together. In this section, users can control their clustering options, including the zoom level at which clusters first appear, the geographic area each cluster represents, and the size of the cluster on the map.