Managing data and planning for projects is complemented using the Google Earth viewing options available in TBC. The first option is using the Google Earth command. This feature allows you to transfer survey data through a KML file into Google Earth.
The offset fields allows you to apply necessary translations to the data to better match imagery in Google Earth as they may initially line up to a certain accuracy. Offsets vary depending on the accuracy of the imagery in Google Earth. Rectifying and combining images taken from differing orientations and altitudes will cause the superimposed survey data to appear to be located incorrectly.
The Altitude mode allows you to export the data with two methods:
- Clamp to Ground ensures all points are located at ground level.
- Absolute ensures all points are displayed at their correct elevation based on the offset value you enter in the Elevation box.
The Google Earth command supports viewing these data types from TBC: HALs, baselines, contours, line and point features, observations (displayed as lines), photos, trajectories, and event markers.
Another option for visualizing data in Google Earth is using the KML/KMZ exporter. How do you choose which export option to use for Google Earth?
- Output kml file creates a KML (.kml) file that contains 3D geographic coordinates only. It does not include photo images.
- Output kmz file creates a ZIP file that contains a KML file and all referenced photographic image files. The images can be viewed by selecting the image icons in the browser used to open the KML file.
The same offset and altitude options exist in the KML/KMZ exporter.
Now you can view your data in Google Earth for project planning and management and an added deliverable for clients.
Note: The difference between KML and KMZ files is that the KMZ file is a compressed version of the KML.
Don’t forget to send us a message if you would like to see a certain feature highlighted in next week’s tip.
Have fun this week using TBC and as always, Happy Surveying!