Aerial Videography
 
The Fish & Wildlife Information Exchange
National GAP page
U.S. Geological Survey

Table of Contents (click dot to jump to section or click link)

Search Aerial Videography Website Training Course
Introduction Location and Dates of Flights
Uses of Aerial Video GAP Links
Why Use Aerial Video? Other Applications
What is Video Interpretation Based On? References
How is Video Collected? Aerial Videography Equipment List
Interpretation Aerial Video Services
Video Slideshow Contact Information

Introduction
 

In 1994, the Fish and Wildlife Information Exchange (FWIE) began work on the Virginia GAP Analysis Project (VAGAP). The goal of VAGAP is to determine the biodiversity of the Commonwealth of Virginia and to help set conservation priorities. The product is a set of map layers, including land use/land cover and land management, that will be linked to a wildlife database and species-habitat models in a Geographic Information System (GIS). The process involves the collection, organization, manipulation, and analysis of spatial data. FWIE has several collaborators, including the Virginia Department of Game and Inland Fisheries (VDGIF), the Multi-Resolutional Lands Characteristics (MRLC) Consortium, and the Biological Resource Division of USGS.

 

 
 
 

Uses of Aerial Video

Aerial videography (or "video") was used by VAGAP for three reasons:

  1. Creation of models to predict land cover-- Aerial video will be used to collect data that will help us create models of land cover. Aspect, slope, elevation, and other physical features influence where certain cover types are likely to occur; therefore, site characteristics of interpreted points can be analyzed to predict land cover distribution across Virginia. Land use patterns are also useful in modeling, and can be derived from aerial video interpretation.

    2.  
  2. Signature generation-- Signatures are ranges of reflectance in the pixel values of satellite images. Image-processing programs use signatures to recognize different land cover types. Known locations of a land cover type are used to analyze a much larger area, such as a Thematic Mapper (TM) scene, to identify locations of that land cover type. For example, we identified agricultural lands with aerial photos and other datasets, and marked the agriculture pixels in a satellite image. The spectral values of those pixels were analyzed with PCI (EasiPace)(tm) and a signature was generated. This signature was then applied to the entire TM scene, and all pixels with similar spectral values were labeled as agricultural fields.

    3.  

     

    A large number of sampled points are needed to accurately delineate the spectral value of a land cover type. Aerial video can provide land cover data that is useful for signature generation. Some land cover types, such as shrub and mixed deciduous forest, have a highly variable spectral signature; because they are harder to identify with certainty, these types may require larger datasets.
     

  3. Accuracy assessment of the Virginia Land Cover Map Layer-- Another use of aerial video is in accuracy assessment. We need some way to determine the accuracy and the sources of error in the land cover maps. Error may be attributed to several sources, including the influence of clouds or topography on classification of the satellite image, spectral mixing (see Signature generation), land cover change, and spatial inaccuracy of sampled points or satellite images. Interpreted aerial video points will be overlaid onto the classified land cover maps and compared (e.g., is a Chestnut Oak forest correctly classified as such on the satellite image, or has it been labeled Red Oak forest or Agriculture?). Approximately 1/3 of the interpreted aerial video points will be reserved for accuracy assessment.
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Why Use Aerial Video?
 
There are two basic choices for collecting land cover data: field work (or ground truthing) and remote sensing. Remote sensing is less expensive and faster because personnel are not required to sample land cover on the ground. Aerial video is a form of remote sensing where video is collected while flying transects over the area of interest. Aerial video has several benefits:
Of course, aerial video has a few disadvantages as well:
How is Video Collected?
 
Our interpretation procedures are modeled after Slaymaker et al. (1996). For more detailed information, see the New England GAP page. The video is recorded onto Hi-resolution 8 mm videotapes from a small fixed-wing aircraft with two cameras. One camera is set for a wide angle view, approximately 0.5 km wide, and the other is zoomed to 12X to show a 30m swath at the center of the wide angle view (Slaymaker et al. 1996). We obtained very good images flying at a speed of 90 mph approximately 2000 ft above the ground. A Global Positioning System (GPS) unit detects the coordinates of the point on the earth directly below the plane, and the coordinates are coded on the frames of the video by the Horita(tm) time code generator. The video is recorded onto the 8mm tapes, and the point information is collected in a database on the laptop computer.

 

 
 
 

Interpretation
 

After completing the flight, we have a database consisting of points in Trimble *.ssf format. This file is processed and differentially corrected in Trimble Pathfinder Office(tm), resulting in a file that can be exported as a shapefile (*.shp) and viewed as a theme in ArcView(tm). The TM scenes for Virginia are added as themes in ArcView in the NAD27 (UTM) coordinate system. We found the optimal combination of TM scene bands for viewing vegetation to be 3,4, and 5 displayed in the Blue, Red, and Green channels, respectively. The time code on the wide and zoom video frames is synchronized and matched to the geographic position on the TM scene, and the vegetation at that location is interpreted. Attribute data, including tree species identified, land cover type, and site characteristics, are entered into the database.

 
The image shows the display we use for interpreting in ArcView. The pink dots are the points in the flightline database, which is overlaid onto the TM scene (in the background) along with road and river coverages. Land cover information is entered into the table in the bottom of the graphic. (Click on the image for a complete view (125K JPEG)). Video Interpretation ArcView Image

What is Video Interpretation Based On?

Traditional field work provides the basis for video interpretation. Interpreters must spend time visiting sites and labeling sample video images for two reasons: 1) the interpreters learn to identify individual species and land cover types, and 2) each land cover type is well-represented in a "key" consisting of interpreted images. We utilize field guides and other means of vegetative mapping handbooks, including:


Video Slideshow

Our collection of ground-sampled images has resulted in a video slideshow.  It is a series of slides in Microsoft PowerPoint. Video interpreters open these slideshows and toggle between the slides and the project while interpreting in the lab.

 

 

Training Course
        Training courses are available upon request. For more information CMI Outreach and Education
 

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Location and Dates of Flights
(Click on image for a complete view (ca. 75K JPEGs)).
Spring Flight Video 1996Fall Flight Video 1996 and 1997

 
The following is a list of flight dates and locations in Virginia, for those who might be interested in data from a certain area of Virginia. (Note: the 1995 flights were test flights; the data quality is variable)

 
File Name Region Location/Unique Areas 
11/12/95  MTN  West 
11/14/95  MTN  Craig Creek area - Southwest
11/15/95  PIED  Western/Central
11/16/95  PIED  Central/Eastern
11/17/95  CST  Coastal
4/22/96  PIED  Northeast
4/23/96  CST  Southeast
4/24/96  CST  Chincoteague Barrier Islands - Southeast
GDSwamp  CST  Great Dismal Swamp
4/25/96  CST/PIED  Central
Pickett  PIED  Fort Pickett - South-Central
5/1/96  MTN  Blue Ridge - Northwest
5/21/96  MTN  Southwest
Shenand  MTN  Shenandoah National Park - Northwest
10/14/96  MTN  (Mostly Maryland, some Central VA) 
10/15/96  MTN  Southwest
10/16/96  MTN  West-Central
10/21/96  MTN  Northwest 
11/04/96  CST  Northeast
11/05/96  CST  Southeast
10/16/97  PIED  Central

GAP Links

Other Applications of Aerial Video
 
Aerial video is useful for many types of spatial analyses. Land change surveillance, development planning, and protection of lands are a few of the many uses for videography. The scale of the application may also vary from low-altitude flights for specific targets to high-altitude sampling of general land cover. A small selection of several Web sites involving aerial video includes:

References

A list of articles (by no means complete).

 Anderson, J.R., E.E. Hardy, J.T. Roach, and R.E. Witmer. 1976. A land use and land cover classification system for use with remote sensor data. U.S. Geological Survey Professional Paper 964, U.S. Government Printing Office, Washington, D.C. 28pp.

 Driscoll, R.S., D.L. Merkel, D.L. Radloff, D.E. Snyder, and J.S. Hagihara. 1984. An ecological land classification framework for the United States. U.S.D.A. Forest Service, Miscellaneous Publication 1439, Washington, D.C. 56pp.

 Everitt, J.H., D.E. Escobar, R. Villarreal, J.R. Noriega, and M.R. Davis. 1991. Airborne video systems for agricultural assessment. Remote sensing and the environment 35:231-242.

 Graham, L.A. 1993. Airborne video for near-real-time vegetation mapping. Journal of Forestry 91:28-32.

 Mausel, P.W. and D.J. King. 1992. Airborne videography: Current status and future perspectives. Photogrammetric Engineering & Remote Sensing 58:1189-1195.

 Scott, J.M., F. Davis, B. Csuti, R. Noss, B. Butterfield, C. Groves, H. Anderson, S. Caicco, F. D'Erchia, T.C. Edwards Jr., J. Ulliman, and R.G. Wright. 1993. Gap Analysis: Protecting biodiversity using geographic information systems. Wildlife Monograph 123, in press. 141pp.

 Slaymaker, D.M., K.M.L. Jones, C.R. Griffin, and J.T. Finn. 1996. Mapping deciduous forests in southern New England using aerial videography and hyperclustered multi-temporal Landsat TM imagery. pp. 87-101 in Gap analysis: a landscape approach to biodiversity planning. J.M. Scott, T.H. Tear, and F.W. Davis, eds. American Society for Photogrammetry and Remote Sensing, Bethesda, MD.

 Society of American Foresters. 1980. Forest cover types of the United States and Canada. F.H. Eyre, ed. Society of American Foresters, Washington, D.C. 148pp.

 United Nations Educational, Scientific and Cultural Organization. 1973. International classification and mapping of vegetation. Paris. 35pp.

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Aerial Videography Equipment List: Flight Equipment
  1. Canon Camcorders (2)
    1. power cords
  2. Sony Recorders (2)
    1. power cords
    2. s-video cables from video out to TV monitors
    3. cables from video camcorders to Horita to recorders
  3. Horitas (2)
    1. one black GPS Horita (GPS1)- generates timecode from the GPS1 to be written onto the wide angle video (GEN)
    2. one white Horita (TG 50)- reads the timecode generated by the GPS1 and writes it to the zoom angle video
    3. power cords
  4. GPS unit
    1. one recharging power cable plug with a female cigarette lighter end
    2. one power cable with cigarette lighter male end to fit the female end above (cable goes to bottom of GPS to power the receiver and the male cigarette lighter end goes into one end of the splitter coming from the 12 v. battery)
    3. antenna with 25 ft cord- fits into the back of the GPS unit
    4. communication cable - from GPS to computer; 5 pin round end from GPS to 9-pin connection going into the cable which splits the signal to the computer and to the Horita
  5. Monitors
    1. one 4 inch screen with power cord (may be replaced or supplemented with a PCMCIA card)
    2. 1 power inverter with male cigarette lighter end.
    3. Y cigarette lighter (1 male to 2 female ends)- male end goes to battery adapter (see #4) and the GPS unit connects to one of the female ends. The power inverter goes into the other female end.
    4. 1 cigarette lighter adapter - has clasps for the battery terminal and a female cigarette plug at the other end
    5. 2 power strips - one backup
  6. Laptop
    1. power cord
    2. Trimble Pathfinder key
    3. Geolink Key
  7. Camera mount
  8. Plastic Wind shield
  9. 12v Battery

 
Aerial Videography Equipment List: Lab Workstation
(Note: use of product names does not imply endorsement by VAGAP or FWIE )
  • 2 color video monitors
  • 2 Hi8 Video Cassette Recorders
  • 1 remote control (runs both recorders simultaneously)
  • 1 PC workstation equipped with:
  • ArcView 3.0
  • MIPS 5.6 (image processing software)
  • PathFinder Office (Trimble GPS software)
  • Snappy (screen capture software)
  • Fauve Matisse (image manipulation software)
  • Microsoft Office (Word, Excel and PowerPoint for reports and image display)

    • Patience enough to interpret video

 
Aerial Videography Equipment List: Other Supplies Source 
Wind Shield  NRG 
15" TV Monitor (2)  Tm-131SU JVC 
1 - 12 volt car battery and 1 power strip (power converter) 
Miscellaneous cables, connectors, etc... 
Hi 8 video tapes
Camera Mount VT Engineering


Aerial Video Services

Equipment and personnel are available to conduct aerial videography flights for specific areas or other regions of the U.S. We maintain all equipment required for the flight and fly through local airports. If interested in obtaining videography data, contact Jeff Waldon or Stacy McNulty at the Fish and Wildlife Information Exchange for a cost assessment or more information.

For More Information
 
Fish and Wildlife Information Exchange 
203 W. Roanoke Street 
Blacksburg, Virginia 24060 
540-231-7348 voice 
540-231-7019 fax 		 The Fish & Wildlife Information Exchange

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Page last updatedDec.9 1999 sm CLICK HERE TO VISIT THE TOP 1000! Aerial Videography Stats