FlatGeobuf Data Source

FlatGeobuf is an open 3D data format developed to efficiently stream large, heterogeneous 2D vector geodata. It is based on the FlatBuffers serialization library and uses a spatial index to enable fast querying and streaming of geospatial data. The FlatGeobuf data ource makes it possible to integrate FlatGeobuf data into the VC Publisher and thus into the VC Map.

Please note that the current implementation of the FlatGeobuf data source in the VC Publisher loads all data available in the FlatGeobuf dataset into memory. Thus the behavior of FlatGeobuf datasources is similar to GeoJSON datasources. It is recommended to test the datasource with your specific FlatGeobuf datasets to ensure compatibility and performance. If you have large FlatGeobuf datasets, it is recommended to use the Vector Tiles datasource instead and the FlatGeoBuf tile provider (see Vector Tiles documentation), which is designed for efficient streaming of large geospatial datasets.

The following table provides an overview of the options:

Option	Description
Name	Name of the Datasource.
Description	Description of the Datasource (optional).
Bounding Box	Describes the bounding box of the data. Clicking the button "Edit Bounding Box" opens a new map window where a bounding box can be defined interactively. Clicking the button "Draw new extent on map" activates the bounding box mode, allowing the user to define a bounding box by clicking twice on the map (e.g., top-right and bottom-left corners of the bounding box). The coordinates of the bounding box are automatically adopted in EPSG 4326. Clicking the button "CLOSE" closes the map window.
URI	URI of the datasource.

Option

Description

Name

Name of the Datasource.

Description

Description of the Datasource (optional).

Bounding Box

Describes the bounding box of the data.
Clicking the button "Edit Bounding Box" opens a new map window where a bounding box can be defined interactively. Clicking the button "Draw new extent on map" activates the bounding box mode, allowing the user to define a bounding box by clicking twice on the map (e.g., top-right and bottom-left corners of the bounding box). The coordinates of the bounding box are automatically adopted in EPSG 4326.
Clicking the button "CLOSE" closes the map window.

URI

URI of the datasource.

Further information regarding the URI

The URI must point to a FlatGeobuf file and the URI must end with ".fgb". A valid URI looks as follows: https://github.com/…/countries.fgb.

EPSG code

please specify the EPSG code of the coordinate reference system (CRS) used in the FlatGeobuf dataset. This is necessary to ensure that the data is correctly georeferenced and displayed in the VC Map. The EPSG code should be provided as an integer value, for example, "4326" for WGS 84.

Proj4 String

please specify the Proj4 string of the coordinate reference system (CRS) used in the FlatGeobuf dataset. This is necessary to ensure that the data is correctly georeferenced and displayed in the VC Map. The Proj4 string should be provided in the standard Proj4 format, for example, "+proj=longlat +datum=WGS84 +no_defs" for WGS 84. Or alternatively click on Static to fetch the proj4 string from https://epsg.io.

After all settings have been made, the data source must be saved. It can then be viewed as a 2D map or as an overlay of a terrain layer in the preview (button 'Activate Map').

Data Preview

The data preview allows a visual check of the configured data source before publication. It displays the data in the map window using the selected projection and within the defined extent. Users can interactively pan and zoom the map to review the display.
Changes to the data source or the extent are applied to the preview after clicking “Reload Map.”