Data layers are external spatial data sources which can be loaded to map and provide location context to data from power BI. This section is an extension of Measure Data Layer to allow for specifying datasource. Settings not discussed in this page like Projection, Show label are exactly same as Measure Data Layer.
Data Layers are joined to power BI dataset using the field(s) specified in category field bucket. This join is similar to a left outer join with data source on the left.
Matched features - Data source rows with a matching row in power BI dataset is referred as matched features. Unmatched features - Rows which cannot be matched.
Data map visual supports drill down and up on data points. Drill through feature can be achieved by adding more than 1 fields in category field bucket. Each drill level require a corresponding data layer to be configure. Data map can support upto 7 hierarchical level, only the data layer corresponding to drill level is displayed.
Refer image above to achieve drill through.
- Specify field hierarchy
- Set Number of Data Layers to number of fields in category bucket
- Configure data layer for each category. In the above example, Data Layer 1 corresponds to Region Name field and Data Layer 2 corresponds to Local Government Area
This setting allows us to specify datasource URL. Data layers should be served over HTTPS and have CORS enabled.
Data map supports following data sources types:
- GeoJson - URL pointing to a GeoJson file, should have extension .json or .geojson
- KML - URL pointing to a KML file, should have extension .kml
- ArcGIS Feature service layer - URL should point to a feature layer
Join Field Name
Field name in data layer source which is used to establish join with corresponding Power BI category field. Field name is case insensitive, field value used for establishing join is case sensitive.
Data Load Strategy
This setting defines how the data is loaded to map. This setting is applicable only for ArcGIS feature service layer, other data sources will always use Load all features strategy.
- Bounding box - Loads all features in current map extent, ideal when we have few features and at the features are geographically distributed.
- Load all features - Loads all features from datasource, default behaviour for GeoJson and KML data sources. Ideal when we have small number of simple features like 1000 to 5000 point features.
- Tiles - Loads features in concurrent tile extents, each tile is 256X256 pixel in size. Ideal when we have more features that are geographically distributed. More suited for point features for line and polygon features it's recommended to use dynamic tiles.
- Dynamic Tiles - Similar to tiles except generalizes features at lower zoom level to improve load performance. Ideal for large number of line and polygon features. As users zoom to higher zoom level, less generalised features are loaded.
This setting is applicable only for ArcGIS feature service layer. This setting controls maximum number of features loaded in each requests, this setting is useful feature reduction technique.
When using Load all features strategy make sure this number is greater than or equal to number of features on the layer. In this strategy data is loaded only once and will stop loading once Maximum feature is reached.
This setting defines if unmatched features are displayed on the map, this is turned off by default. It could be useful under certain scenarios to display unmatched features, for example data quality reports where spatial data source is treated as truth.