Open Source Gis In Support Of Compliance Checks For Lidar Data

Digital elevation models from LiDAR observations are very complex to be tested. This is principally due to the impossibility to accurately position the ground point from which the signal is reflected back. For this reason it is necessary to find solutions for data harmonization and compliance checks.In recent years Veneto territory has been the object of many airborne LiDAR surveys, performed by different subjects; subsequently Veneto Region developed several methods of quick dataset validation, regarding both the acquisition phase and the quality testing of final products.Some semi-automatic control methods based on different GIS software were processed in order to overcome the difficulties above mentioned. GIS software also allow to make comparative tests on large scales.In the following paper, a comparison between two different elevation models derived from LIDAR observations is displayed. The study was fully performed using QGIS, and provided good results; anyway, the method here considered needs to be calibrated and proved against topographic surveys.The results obtained from the different LIDAR datasets are comparable, showing a good correspondence. They are very useful in order to assess if systematic errors are present on large areas. Moreover, it is possible to define clear correlations between DTM discrete precision classes and different land cover or slope categories derived from the related thematic maps.