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Multiple sensors from differential GPS to Wireless Camera

The mapping scenario MovingObjects represents the modern approach to making maps. If you simply watch the traces spread over the screen (with-out the map image), you can watch the map drawing itself. The availability of GPS Tracker For Car allows anyone to collect map data at low cost and with high accuracy. Every navigation system and many smartphones collect data all the time—and the manufactures know how to retrieve them. This is changing the mapping business dramatically as it doesn’t require geo- and cartographic skills.

Commercial vendors of digital maps have large field teams all over the globe, driving (tens of) thousands of kilometers every month to collect every piece of information that might be of interest. Since every field trip consumes manpower, time, and money, the field cars are equipped with multiple sensors from differential GPS to video cameras. For best accuracy, the measurements of the GPS are compared to the traveled distance of the car and each change of heading is marked. Fieldwork has to consider the difference of the distance traveled between left and right tires, tire pressure, wheel slip, temperature, etc.

Due to different time zones and many other factors, it makes sense to always have the map available online for the field team. Map engineers can check-out (download) any part of the map, edit it, and finally check it back in (Vehicle GPS Locator ). Large teams have to be synchronized, concurrent editing has to be reintegrated, and precise timing schedules exist, when a map is locked and flushed to snapshots and extracted to different formats in consecutive steps. The geometry represents the fundamental grid for any map and the majority of it needs to be collected only once. However, the collected traces can not be integrated directly into a map. Besides deviating slightly from the real road geometry, there are simply too many positions. The scenario RGB-BUELL includes about 50 traces with about 40,000 points. Each trace can be loaded and compared against the OpenStreetMap data with the Java OpenStreetMap Editor (JOSM). Digital street maps have more to offer than geometry and administrative coding—they include traffic rules.4 Observing traffic is a main reason for gathering map data in the field.

Field workers have to be capable of recognizing complicated or dangerous driving situations and add important guidance assistance to the map data. After the geometry is in place, the field team researches for relevant information to be added to the map. Each map element is digitized with meaningful attributes. The sources for road names and house numbers range from paper maps to phone calls with local authorities. Usually field offices are located in their region of responsibility to ensure as much local knowledge as possible. The graphical front ends are used to control the accuracy and position of each node, to move them to the centerline of a road, and so on. The heart of a digital map is the map specification. The specs describe how to code every single piece of map data. Global specifications enable customers to process each map regardless of coverage and cultural differences ( Wireless Security Camera System ). Map data can be processed in one tool chain to produce general functionality to specific guidance in complex situations.

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