Browsing by Author "Boström, Mårten"
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Boström, Mårten (Helsingin yliopistoHelsingfors universitetUniversity of Helsinki, 2011)Orienteering maps are special types of maps. They are designed to give orienteers equal chances to make route-choice decisions. Orienteering maps have traditionally been made using aerial images, LiDAR scanning, old orienteering maps and/or other topographical maps as base material. With one or several as these as the foundation the mapmaker then does the field work in the terrain with pencils after which the material is combined by scanning and superimposing of the data on a Personal Computer. Aerial images and the following stereoscopic evaluation are costly and the field work a tedious procedure so when using these methods, the whole mapmaking process may take up to two years. In this study a GPS-connected tablet-PC running OCAD was used for the whole mapmaking process. The study areas include urban Pikku-Huopalahti, Helsinki and in the rural Ngangao forest in Kenya. The usability of different GPS receivers and the mapmaking software OCAD were tested in different terrains and conditions, as well as at different locations on the globe in order to get comprehensive results. Up until recently the accuracy achieved with affordable GPS receivers has not been sufficient for detailed mapping, but with recent technological advances the cost of accurate receivers are low enough to make this method of mapmaking advantageous. The reception of GPS signals is drastically limited by the tree canopy in equatorial indigenous forests, where the canopy may cover up to 100% of the sky view. A high navigation sensitivity (> 160 dBHz) of the GPS receiver is desired for best GPS reception. The results of comparing GPS reception between receivers in urban terrain also showed variance between the receivers and between differing terrain conditions. The tablet-GPS mapping systems worked well in differing conditions. Even humidity did not cause problems, contradictory to mapping using traditional mapping methods. The accuracy and productivity of the traditional way of making orienteering maps and the Tablet-GPS method were compared. Utilizing the Tablet-GPS method an orienteering map may be produced faster and with enhanced accuracy of the final map.
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