Confluence Retirement

In an effort to consolidate USGS hosted Wikis, the myUSGS Confluence service is targeted for retirement on January 28, 2022. The official USGS Wiki and collaboration space is now SharePoint. Please migrate existing spaces and content to the SharePoint platform and remove it from Confluence at your earliest convenience. If you need any additional information or have any concerns about this change, please contact myusgs@usgs.gov. Thank you for your prompt attention to this matter.

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Comment: revised to point to the quick checklist that Alexandre and Liz created.


Quick Start Guidelines

Most cameras work for capturing video of sufficient quality for LSPIV processing. 
  • Avoid wide angle lens, and other sources of image distortion. 
  • Look for resolutions at least 640 x 480 pixels.
    Record video for at least 1 min to enable the best chance for quality results. 
  • The camera platform (tripod, person, etc.) should be as stable as possible. 
    • If a tripod or other fixed mount is not an option, try to stabilize the image by bracing against a fixed object, or shooting from your knee.
       
  • If taking an oblique-angle video (i.e., from the ground/bank), avoid perspective angles lower than 15°. 
     
  • Video captured perpendicular to (directly above) the flow, and can see the entire region of interest and fixed locations is acceptable.
    Ensure the frame of view of the video includes the entire width of the measurement cross section, and has the highest angle (as close to 90°) as possible (For example, looking down on the water is preferable to looking across the water).
    Ensure that the frame of view includes fixed locations (e.g. banks, trees, structures) on both sides of the channel within the image. 
  • Include a minimum of four (4) fixed and permanent reference points, where the distances between those points can be measured, either at the time of recording or at a later date (stakes or other markers may be temporarily installed if existing reference points are not available or suitable).
  • Film a zone where surface flow disturbance patterns are more uniform with time. For example, wind waves going upstream will effectively reduce downstream surface velocities.
    The best river sections for capturing video have stable bottoms not subject to erosion. It is understood that this is not always known or possible.
    Avoid reflections, shadows, and sparkling patterns on filmed surface.
  • Consider the effects of pier wake and other flow disturbances on velocities when taking video from a bridge. It may be preferable to shoot video looking upstream of a bridge, or from the banks depending on how the bridge affects the flow.
  • The printable Quicksheet below is a handy guide to print out and have in your gear kit for ensuring you have all of the necessary measurements and data for a quality LSPIV video. 

    View file
    nameLSPIV_Guidelines_OnSiteChecklist_20171006.pdf
    pageGuidelines for the collection of video for Large Scale Particle Velocimetry (LSPIV)
    height250

    Points of Contact

    Frank Engel (USGS)
    217-328-9774
    fengel@usgs.gov
    405 N. Goodwin Ave.
    Urbana, IL, 61801


    Elizabeth Jamieson (ECCC)
    613-992-9337
    Elizabeth.jamieson@canada.ca
    Head, Hydrometric Monitoring Technology Unit
    Water Survey of Canada - Relevés hydrologiques du Canada


    C. Marcelo Garcia (CETA)
    National University of Cordoba, Argentina
    cgarcia2mjc@gmail.com