Development and Utilization of High Precision Digital Elevation Data taken by Airborne Laser Scanner

Osamu AKUTSU, Masataka OHTA, Tamio ISOBE Hisamitsu ANDO, Takahiro NOGUCHI and Masayuki SHIMIZU


Disasters caused by heavy rain in urban areas bring a damage such as chaos in the road and railway transport systems, power failure, breakdown of the telephone system and submersion of built up areas, subways and underground shopping arcades etc.
      It is important to obtain high precision elevation data which shows the detailed landform because a slight height difference affects damages by flood very considerably. Therefore, the Geographical Survey Institute (GSI) is preparing 5 m grid digital terrain model(DTM) based on precise ground elevation data taken by using airborne laser scanner.
      This paper describes the process and an example of the use of a 5 m grid digital data set.


1. Introduction
2. Airborne Laser Scanning
3. Preparation of the 5 m grid digital elevation model
  3.1 Ground data acquisition process
    3.1.1 Planning
    3.1.2 Airborne Laser Scanning and Digital image acquisition
  3.2 Verification of Accuracy
    3.2.1 Rate of “No data”
    3.2.2 Side-lap comparison
    3.2.3 Comparison at verification points
  3.3 Processing of Digital data
    3.3.1 Measurement data processing
    3.3.2 Ground image (Orthophoto)
    3.3.3 5 m Grid data
    3.3.4 Water Polygon
    3.3.5 Ground surface attribute
4. Verification of data quality
  4.1 Rate of “No data”
  4.2 Side-lap comparison
  4.3 Comparison of verification points
5. Comparison with other data
  5.1 Comparison with 50 m grid (elevation)
  5.2 Comparison with Land Condition Map
6. Data utilization
7. Data development and future issues to be solved
8. Conclusion