U.S. Geological Survey Data Series 761
Two separate records of flight navigation were collected during the survey.
The first was a continuous ASCII text file from the PLGR GPS that recorded only latitudes and longitudes for the entire flight at 30-sec intervals. No time values were recorded by the PLGR. The second navigation record was recorded in the subtitles of the video footage that was shot continuously during the survey. Navigation (latitude and longitude), and time (hours, minutes, and seconds in UTC) were continuously imprinted on the video throughout the flight using a Trimble Centurion GPS. In order to produce a digital record of the navigation that included time, the latitude, longitude, and time were manually extracted from the video every 5 minutes, and these values were matched to the latitude and longitude in the PLGR file. Using Microsoft EXCEL 2004, the time values for the remaining navigation fixes were interpolated between the known 5-min values.
A Nikon MF-14 camera data back marks the date (day of month) and time (hr:min) on the lower right corner of the slide film. These values were entered from the photographs into an Excel spreadsheet. It is assumed, for the purposes of location, that the photographs were taken at a constant rate during any given minute of flight. To assign a time value in seconds to each photograph, the number of photographs taken during each minute was evenly distributed across that minute. For example, if 15 photographs were taken during minute 19:00, we assume that a picture was taken every 4 sec. The photographs are assigned the time values 19:00:00, 19:00:04, 19:00:08, and so on. It should be noted that the positions assigned to each photograph are an estimate of the aircraft position, not the location of the landmark photographed.
The time values were then cross-referenced to the estimated latitude and longitude values discussed above to assign positions to each photograph.The processed navigation file can be accessed from within the nav folder or by clicking the following link: 03cch01.csv (762-KB CSV file). The file contains 12 fields that are defined as follows:
Field 1: LATITUDE - estimated latitude (decimal degree) positions of photographs
Field 2: LONGITUDE - estimated longitude (decimal degree) positions of photographs
Field 3: HR:MIN:SEC - hour:minute:second (UTC)
Field 4: SLIDE - slide filename (year, date, roll number, and slide number)
Field 5: SLIDE_URL - Web location of the slide
Field 6: CONTACT_SHEET_URL - Web location of the contact sheet
Field 7: YEAR - year the photo was taken
Field 8: MONTH - month the photo was taken
Field 9: DAY - day the photo was taken
Field 10: PRE_POST - type of survey conducted (post-storm)
Field 11: STORM - name of the storm
Field 12: GEO_AREA - locations surveyed
Navigation was extracted from a Rockwell Collins PLGR unit, which recorded a continuous ASCII text file through out the survey. Locations were recorded at a 30-sec interval. No time data were collected.
The raw navigation files can be accessed from within the nav folder or by clicking the following links: 03cch01_0321plgr.txt (45-KB ASCII text file), 03cch01_0322plgr.txt (20-KB ASCII text file), 03cch01_0323plgr.txt (25-KB ASCII text file). The file contains 10 fields separated by a space that are defined as follows:
Field 1: NUMBER - sequential number
Field 2: WAYPOINT NUMBER - waypoint sequential number
Field 3: LATITUDE - latitude (decimal degree) positions of photographs
Field 4: LATITUDE - latitude (degree minute second) positions of photographs
Field 5: LONGITUDE - longitude (decimal degree) positions of photographs
Field 6: LONGITUDE - longitude (degree minute second) positions of photographs
Field 7: ALTITUDE - altitude in feet
Field 8: DATUM - WGS84
Field 9: ID NUMBER - year the survey was conducted
Field 10: PROJECTION - latitude/longitude - degree minute second
Navigation and time were continuously imprinted on the video throughtout the flight using a Trimble Centurion GPS. At the beginning of each 5-min flight segment, navigation and time were manually extracted from the video footage. These values were matched to the latitude and longitude in the PLGR file because the PLGR did not record time values.
The manually extracted navigation file can be accessed from within the nav folder or by clicking the following link: 03cch01mnl.csv (8-KB CSV file). The file contains eight fields separated by a space and defined as follows:
Field 1: LATITUDE - latitude (degree and decimal minutes) positions of photographs
Field 2: LATITUDE - latitude (decimal degrees) positions of photographs
Field 3: LONGITUDE - longitude (degree and decimal minutes) positions of photographs
Field 4: LONGITUDE - longitude (decimal degrees) positions of photographs
Field 5: HR:MIN:SEC - hour:minute:second (UTC)
Field 6: YEAR - year the survey was conducted
Field 7: MONTH - month the survey was conducted
Field 8: DAY - day(s) the the survey was conducted
