Laser scanning is a technology based on laser pulses transmitted by an active sensor, or a laser scanner, and on accurate location information.
Laser scanning data is typically used to produce elevation models, as the technique is particularly well suited for providing elevation data of the ground and covered areas, such as forests.
In addition to the elevation data of the ground, laser scanning also provides information about other objects on the ground, such as roads and trees. The laser scanning technology can be used for making inventories of forests and for preparing three-dimensional city models.
Laser scanning used to produce new elevation model
In 2008, the National Land Survey of Finland (NLS) began to provide laser scanning data for producing a new national elevation model.
After the completion of scanning flights in spring 2013, the laser scanning data available covers an area of approximately 235 000 square kilometres. An index map (in Finnish) shows the location of the laser scanned areas. The minimum point density of the NLS laser scanning data is half a point per square and the elevation accuracy of the points is 15 centimetres. Read a detailed specification of laser scanning data under the heading Collection and Services.
Part of a 2 meter grid DEM. Even the smallest details on the ground can easily be seen.
Laser scanning data and the elevation model benefit all parties
Accurate elevation data is required for planning various activities in the society and for being prepared to face diverging circumstances. The NLS laser scanning operations have been aimed particularly at areas with high risk of flooding and on densely populated areas, where accurate elevation data is required for compiling flood maps.
Laser scanning data and the new elevation model can be utilized in activities and plans associated with environmental protection and diverging circumstances, such as downpours and surface runoffs. Elevation data is also utilized for mapping, land use planning and for planning built environments. To detect minor details of the ground in laser scanning data is of use in many geological applications and might be of interest for archaeologists, for example.
Using the laser scanning data the NLS provides an elevation model, which is to be incorporated in the Topographic database. A more precise elevation model allows calculating even more accurate orthophotos.
A variety of examples showing different applications of laser scanning data and the elevation model are found under the heading application examples (in Finnish).
Planning future laser scanning areas
Laser scanning is aimed at areas where more accurate elevation data is most urgently required. When planning new laser scanning areas the NLS closely cooperates with different actors in the society.
For more information about cooperation, please contact the Aerial Image Centre. Information Services is, in turn, responsible for selling laser scanning data.