Abstract

Fast-mapping mosaics, orthophotos and DTM for GIS
Track: Business
Authors: Joseph Paiva

Whether DTM or photomosaic or something in-between, there are a variety of data sources to access for the backdrop of a GIS. However, there are many applications where a ready source of this background information is not available. This may be due to the remoteness of the location, or it may be that the detail required, especially when an engineering project is being planned, is not sufficient from commercials sources. The solution is to then contract with photogrammetrists or surveyors to map the area of interest. For areas of approximately 20 square kmilometers (0.75 sq mi) or less, unless the subject area is just a few hectares, when a total station or RTK GPS might be preferred, the ideal solution for speed and the accuracy desired is photogrammetry. However for these small areas, this technology is usually cost-prohibitive. Even though photogrammetry over large areas has an economic advantage over ground-based surveys, the high fixed costs of a project make smaller projects have high average costs per unit of area. Today, a solution that is photogrammetric but not conventional is possible. That solution is the use of ultralight UAV (unmanned air vehicles) as photo robots, coupled with photogrammetric software that is optimized to work with imagery from such robots. In this paper, after discussing the basic technology and processes, a test case is presented illustrating the visual, cartographic and economic benefits of using such a solution.