Geomatics Engineering
Precise positioning of cars, ships and airplanes using GPS, mapping of the impact of climate changes using Earth observation satellites, and combining spatial information for analyses and decision making are all examples covered by Geomatics that use advanced mathematics and information technology. Geomatics Engineering covers a variety of disciplines in Geodesy, Geoinformatics, and Earth Observation and focus on building expertises that are used widely in surveying, mapping and GIS as well as in developing space methods for Earth observation and GPS for a variety of applications.
Satellite Positioning
The GPS marked has exploded through the last years and more is expected to come. Professional users in Surveying use GPS. Car, ship and airplane navigation use GPS. Fleet management and rescue missions use GPS. The future European satellite navigation system Galileo will enhance those possibilities.
The positions are determined from signal from a number of satellites flying at about 20,000 km altitude. To obtain accurate positions we have to correct for clock errors and atmospheric delays. We also need to use advanced math such as integer arithmetic and stochastic inversion to solve the problems.
Mapping
Mapping of infrastructure, topography and vegetation is fundamental in a modern society. How do we get from point A to point B. Where should we put the industrial zone and where should we go hiking. Maps are used in most decision making processes. Google Earth and Google Maps has really demonstrated how aerial and satellite images can give us useful information.
Basic tasks of image analysis are used when map data are retrieved from aerial photos or satellite imaged. Also advanced methods for segmentation and classification are used for mapping purposes.
The topography may be mapped using laser scanners in helicopters, airplanes and even satellites. The technique generates huge amounts of data that should be accessed and processed in an efficient way using advanced methods for error detection and for gridding.
Geographic Information Systems
A lot of information has a time and location stamp associated with it. In Geographical Information Systems (GIS) all that information may be combined and analysed. GIS may be used for designing special maps to display specific objects. GIS is used in planning and administration, environmental monitoring, security issues and many other applications.
Naturally, the geo-location of the information is crucial for GIS. Mismatch may give unreal results. Visualisation is important to display in the information in an understandable way. Access to the data is equally important as well as the design of the data bases. Web map services such as Google Earth, that combine data over the Internet are developing fast.
Earth Gravity Field
Geodesy is about measuring the size and shape of the Earth as well as on determining its gravity field. The gravity changes from place to place depending on the density of the earth materials below the surface. Also the equi-potential surface called geoid change – up to 100 metres from place to place. This has an impact on the shape of the earth and need to be considered when using GPS.
The gravity field has traditionally been measured using spring-instruments on the Earths surface and advanced vector field theory for converting the measurements into the geoid. Now measurements may be collected in airplanes and by satellite instrumentation. One satellite can determine gravity changes so accurately that mass changes due to ice cap melt and ground water movements may be detected.
Earth Observation
Environmental changes, the impact of climate changes and the safety of the population are new important issues where Earth Observation systems may answer the questions. Does the ice cap of Greenland melt? How much does the sea level rise? Earth Observation programmes by NASA and the European Space Agency ESA focus on developing satellite techniques for mapping environment and other Earth surface features.
Earth Observation comprise of a variety of techniques. Space cameras, infrared sensors, advanced radars and lasers are some of them. Also in this case are a number of advanced mathematical tools are needed to develop methods for processing data.
Scientists in the Danish National Space Center are very active in Greenland carrying out research projects where data are collected from airplanes and the ground using laser scanners, GPS and gravimeters. The data are analysed together with satellite data to provide information about the ice cap and the sea ice coverage.