The technique described provides a quick and inexpensive method of recording interpreted data. Although the accuracy obtained by the method is less than that of photogrammetric plotting it is much more rapid and is adequate for most studies. Vehicle positions are identified using automatic readers in terms of photographic co-ordinates which may be expressed relative to any arbitrary pair of rectangular axes. The photographic co-ordinates of a number of control points, with clearly defined features which appear in ordnance survey maps are also recorded relative to the same pair of axes. The control points can then be used to relate the national grid co-ordiates of any point to the photogrpah. Expressions for co-ordinates are derived for both linear and projected transformations. The linear transformation is particularly suitable for the complex networks of urban streets, and the necessary solution of A set of four equations does not require a large amount of computer time. However the number of control points required is much greater than those needed for projective transformation. Projective transformation is more flexible and allows for any tilt of the camera.

  • Supplemental Notes:
    • Conference on Traffic Data Collection, Leeds University, January 8-9, 1979.
  • Corporate Authors:

    University of Leeds

    Department of Civil Engineering
    Leeds, West Yorkshire  United Kingdom  LS2 9JT
  • Authors:
    • Garner, J B
  • Publication Date: 1979

Media Info

  • Features: Figures;
  • Pagination: 11 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00335300
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Nov 23 1981 12:00AM