A layer is a collection of similar geographic features displayed on a map. These features represent real-world objects and can be points, lines, or polygons (areas). Understanding the properties of layers is crucial for effective map creation and data visualization.
Key Features of a Layer
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Geometry Type: Features within a layer share a common geometry type:
- Points: Represent locations (e.g., earthquake epicenters, cities).
- Lines: Represent linear features (e.g., roads, rivers).
- Polygons: Represent areas (e.g., buildings, parcels). (Feature layers—ArcGIS Online Help | Documentation, Feature layers—ArcGIS Pro | Documentation)
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Data Visualization: Layers are ideal for visualizing data on top of basemaps, providing context and enhancing understanding. (Feature layers—ArcGIS Online Help | Documentation)
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Layer Properties: Many properties can be customized to control a layer's appearance and behavior:
- Style: Control the visual representation of features (color, size, symbols).
- Transparency: Adjust the layer's opacity.
- Visible Range: Define the map scales at which the layer is visible.
- Refresh Interval: Specify how often the layer's data is updated.
- Labels: Add text labels to features for better identification. (Feature layers—Portal for ArcGIS | Documentation for ArcGIS ...)
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Data Management: Layers facilitate efficient data management, especially within GIS platforms:
- Ownership: Control who can access and modify a layer. (Solved: Transfer Ownership of Feature layer generated from... - Esri ...)
- Updating: Support various methods for updating layer data, including direct editing, batch updates, and integration with other systems. (Workflow for Updating AGOL Feature Layers : r/gis, How to update multiple AGOL feature layers using change detector ...)
Examples
- A layer displaying points representing crime incidents.
- A layer showing lines representing roads and highways.
- A layer showing polygons representing different land use zones.
