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Managing Geospatial Layers

The Geospatial Layer Manager defines layers of geospatial data that can be displayed in other products like Find My Nearest. It runs as an iCM Form Shortcut from the iCM Desktop.

The data in each layer is ultimately derived from requests made by End Points. These could be requests to third party APIs and web services, or could query the iCM database. The data returned can be stored within the iCM database to save making repeated requests for data that is unlikely to change.

Layers also hold information like the colour of the map markers for this layer, a Handlebars template, and configuration specific to the Find My Nearest product.

Creating Layers

Layers define geospatial data that can appear in products like Find My Nearest.

Layer Information

Each layer must have a unique name, description and a Geospatial Search End Points to retrieve data from.

PropertyDescription
Name A unique name for this data layer
DescriptionA description that will appear in other products like Find My Nearest
Search End PointAn End Point responsible for retrieving the data. This drop-down lists all of the "search" End Points in the goss.geospatial.layers namespace
Import End PointAn optional End Point responsible for pre importing the data. This drop-down lists all of the "import" End Points in the goss.geospatial.layers namespace

Import TTL

When data for a layer is retrieved it may be stored locally in the iCM database to save repeated requests to third party systems (whether or not this happens depends on the search End Point). The TTL set here determines how long that data should be kept for.

Data that is unlikely to change, like the boundaries of national parks, could be stored for a year or more. You can disable data caching by setting the TTL to 0.

Display

Pick the fill and line colours that should be used when displaying this data. Different products will use these colours in different ways. For example, in Find My Nearest the colours are used in the list views, in the "refine" controls, and in the map markers.

When you create a new layer an example Handlebars template is loaded into the code editor. This template is used by Find My Nearest to populate the pop-up information on the maps and the content of the panels in the list view. The various CSS classes in the example are supported by that product.

Find My Nearest

These settings are specific to the Find My Nearest product.

PropertyDescription
Search TypeWhether the data is "Spatial" and subject to geospatial searches, or "Property" and subject to searches based on a property UPRN (eg bin collection information or local councillors)
Spatial RelationEither "Within" or "Intersects". When set to "Within" results must be entirely within a search area to be returned. When set to "Intersects" results only need to intersect the search area to be returned; this is generally used for large polygons, like park boundaries or flood alerts
Min/Max ZoomControl at which zoom levels the data will be loaded. 0 zooms to the entire globe, with higher numbers increasing the zoom level. These settings will depend on your map provider. High density data, like the positions of streetlights, should only be shown at high zoom levels, perhaps "Min: 14, Max: 19"

Additional Settings

In this release this field isn't used.

Imported Data

Most layers will import data when a search is performed. This stores data locally to improve performance and minimise the number of calls to external systems. Layers may also have a specific Geospatial Import End Points which will fetch all of the possible data for a layer, generally covering the whole country, or even the whole globe.

Importing

If a layer has an import End Point, you can trigger that import from the layer manager using the "Import data" button. Existing data is deleted and a new import will run as a background task.

View Import Area

This action will load a map showing any locally stored regions that have been searched and may contain data.

Layer data fetched from import End Points will generally highlight the entire globe or country (depending on what your import End Point does). Where data is imported as part of a search, the boundaries of the various searches are shown.

For example, this map shows various regions around the UK where people have carried out searches and data has been stored. Future searches performed within these regions will fetch data from the local store, searches performed outside of these regions will retrieve data from the original source.

Viewing Imported Data
 

The regions shown on the map will change as new searches are performed and as old data reaches the TTL for the layer.

Clear Data

This action clears the imported data. You can then either perform a new import or wait for data to be stored as searches are performed.

Last modified on July 14, 2023

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