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This project develops new automatic methods for the mapping of forest roads from airborne laser scanning (ALS) data. Three types of method have been developed: (1) Semi-automatic detection and mapping of roads from a high-resolution digital terrain model (DTM), (2) classification of road centre line segments into predefined elevation gradient intervals, and (3) detection and mapping of vegetation that overlaps roads. Methods 2 and 3 were straight forward to implement, and may be used directly in automatic processing chains. Method 1 is experimental, and may need further improvements before it may be used in automatic processing chains. The methods are implemented as IDL and C code. In addition, the main detection module in method 1 is implemented using a deep neural network and requires a graphics processing unit (GPU).


Deep convolutional neural network architecture for automatic road detection.
Classification of roads by elevation gradient.
Result of automatic detection of overhanging vegetation along roads. Green: vegetation (and also buildings) higher than 1 m outside of roads. Red: vegetation higher than 1 m overlapping roads. White: No vegetation higher than 1 m.


Salberg, Arnt Børre; Trier, Øivind Due; Kampffmeyer, Michael C., 2017. Large-Scale Mapping of Small Roads in Lidar Images Using Deep Convolutional Neural Networks. In: Image Analysis 20th Scandinavian Conference, SCIA 2017 Tromsø, Norway, June 12–14, 2017 Proceedings, Part II. Springer 2017 ISBN 978-3-319-59128-5. pp. 193-204.

Research areas

    Project period



    Automatic mapping of forest roads from airborne laser scanning data: detect and map previously unmapped forest roads, classify forest roads and tractor roads by road steepness, and detect overhanging vegetation.


    Norwegian Mapping Authority, Hamar regional office

    Norsk Regnesentral
    Postboks 114 Blindern
    0314 Oslo
    Norsk Regnesentral
    Gaustadalleen 23a
    Kristen Nygaards hus
    0373 Oslo
    (+47) 22 85 25 00
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    Postadresse: Norsk Regnesentral, Postboks 114 Blindern, 0314 Oslo
    Besøksadresse: Norsk Regnesentral, Gaustadalleen 23a, Kristen Nygaards hus, 0373 Oslo
    Tlf: (+47) 22 85 25 00
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