Layers and Hierarchy of the Map
The Map report item is a data item that is similar to the Graph report item, and allows you to present aggregated data by two hierarchical dimensions or groups.
The GeoLocationGroup defines the geographical component of your data, and the SeriesGroups allows you to group your data in a hierarchical way and display one or more measures over the defined geographical reference. Like the other Telerik Reporting data items, the Map connects to a single data source and provides additional options for sorting and filtering the input data, binding, conditional formatting, and so on.
GeoLocationGroup Hierarchy
The GeoLocationGroup hierarchy defines the data points location in the Map series and acts in the same way as the Category Group hierarchy of the Graph. If the report uses a location provider to obtain the geographical coordinates of the data point from a web service, the grouping expression of the GeoLocationMapGroup is used as a request parameter when calling the geocoding service. To achieve better geocoding results, the grouping expression has to provide as many request details as possible, for example, concatenating a city name with a state or region name and a country name.
ShapeMapGroup Hierarchy
The ShapeMapGroup hierarchy is used only in the ShapeMapSeries setting which provides its own spatial data source, depending on the selected SourceType property. The geographical coordinates of the data points do not depend on this hierarchy and, therefore, it does not provide any geolocation properties.
SeriesGroups Hierarchy
The SeriesGroups hierarchy defines the series at runtime. For example, if you have a group by the Country field in the SeriesGroups hierarchy, the number of the different countries will determine how many series will appear on the Map.
LocationMapSeries Data
The Map item series display aggregated data to visualize one or more measures. At runtime the intersection between the series group hierarchy members and the category group hierarchy members defines the data points in the series. The coordinates of each data point are obtained either directly from the data set through the Latitude and Longitude properties, or by using the Location property of the series GeoLocationGroup. The value of the data point is a measure for its size and is calculated by an expression defined for its Size property.
ShapeMapSeries Data
The ShapeMapSeries that is used in the Choropleth map does not use the series group hierarchy the way it is used in the LocationMapSeries. The series grouping is intended to be used when having a static group because the ShapeMapSeries defines its own grouping over properties that are specific only to this series type such as ColorData and ColorsCount.
Therefore, the ShapeMapSeries data points are created for each category group member and their coordinates are obtained through an external source depending on the series SourceType property. The values of the data points determine their presentation colors and are a result from grouping the values into these ShapeMapSeries-specific groups previously mentioned.
Specifics
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When working with the Map series, it is often useful to have a way to determine the current data point coordinates and display them on a label or use them in a conditional formatting rule.
The evaluation engine provides a way to do so by using the
"= Location"special expression. The evaluation result is an instance of typeLocationand itsLongitudeandLatitudeproperties can be directly accessed. Also, when the selected component in the Report Designer isMapSeriesBase, the Edit Expression dialog will include the Location, Location.Latitude, and Location.Longitude entries in its Fields collection. When using the
ShapeMapSeriesthat obtain their geospatial information from a ShapeFile, the processing engine will automatically generate the"Location.Latitude"and"Location.Longitude"virtual fields in the resulting composite data set. Both serve the same purpose to use the coordinates of the data point centroid in expressions.