3.7. Map window for bounding box selections¶
The Importer/Exporter GUI offers a 2D map window that allows the user to display the overall bounding box calculated from the city model content stored in each 3D City Database instance and to graphically select a bounding box filter for data imports and exports.
There are two ways to open the map windows:
- Choose the entry View -> Open map window from the menu bar at the top of the application window.
- Click the map button on the bounding box dialog available on the Import, Export, KML/COLLADA/glTF Export and Database tabs of the operations window.
The 2D map is rendered in a separate application window shown below.
The map content is provided by the OpenStreetMap (OSM) service and is subject to the OSM usage and license terms. Make sure your computer has internet access to load the map. This might require setting up network proxies (see Section 22.214.171.124). Please consult your networkadministrator.
To display the result of the geocoding query on Google Maps in your default internet browser, simply click the Show in Google Maps button .
A list of usage hints is available at the right top of the map window . Please click on the Show usage hints link to display this list. The map controls are also described in the following.
- Select bounding box: Move the mouse while pressing the ALT key and the left mouse button to select a bounding box. The bounding box is displayed in a light magenta color. Once the left mouse button is released, the coordinates of the bounding box are automatically filled in the Bounding Box dialog on left of the map . If you have opened the map window from a bounding box filter dialog, then clicking the Apply button on the upper right corner of the window  closes the map window and carries the bounding box values to the filter dialog. In addition, the values are copied to the clipboard.
- Lookup address: Right-click on the map to bring up a context menu for the geo location at the mouse pointer. From the context menu, choose Lookup address here. This will trigger a reverse geocoding query using the geocoding service selected in . The resulting address will be displayed on the left of the window . The icon denotes which location on the map is associated with the address, whereas the icon shows where you clicked on the map (see Fig. 3.72).
- Zoom in/out: Use the mouse wheel or the context menu (right-click).
- Zoom into selected area: Move the mouse while pressing the SHIFT key and the left mouse button to select an area. The selected area is displayed in a light grey color. Once the left mouse button is released, the map zooms into the selected area. If the maximum zoom level is reached this action has no further effect.
- Move map: Keep the left mouse button pressed to move the map.
- Center map and zoom in: Double click the left mouse button to center the map at that position and to increase the current zoom level by one step.
- Use popup menu for further actions: Right-click on the map to bring up a context menu offering additional functions such as Zoom in, Zoom out, Center map here and Lookup address here (see above). The Get map bounds function is equivalent to selecting the visible map content as bounding box. Thus, the map will be shown in light magenta and the map bounds are transferred to the Bounding Box dialog on the left .
To close the map, simply click the Cancel button in the upper right corner .
The coordinates in the map window and of the selected bounding box are always given in WGS 84 regardless of the coordinate reference system of the 3D City Database instance.
When opening the map window from a bounding box dialog that already contains coordinate values (e.g., from a filter dialog on the Import, Export or KML/COLLADA/glTF Export tabs or after having calculated the entire area of the database content on the Database tab), the map window will automatically display this bounding box. If the coordinate values of the provided bounding box are not in WGS 84, a transformation to WGS 84 is required. Since the Importer/Exporter uses functionality of the underlying spatial database system for coordinate transformations, a connection to the database must have been established beforehand. In case there is no active database connection, the following pop-up window asks the user for permission to connect to the database.
The Apply button on the upper right corner of the map window  is a shortcut for copying the coordinate values to the clipboard and pasting them in the bounding box fields of the calling tab on the operations window. Furthermore, coordinate values can now be easily copied from one tab to another by simply clicking on the copy button in one of them, say Import tab, with filled bounding box values, changing to another, say KML/COLLADA/glTF Export tab and clicking on the button there. Previously existing values in the bounding box fields of the KML/COLLADA/glTF Export tab (if any) will be overwritten.