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U.S. Geological Survey Data Series 761

# Navigation Data

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#### Home | Acronyms | Contents | Navigation | Photos and Maps | Logs | Metadata

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### Processed Navigation

Two separate records of flight navigation were collected during the survey.

The first was a continuous ASCII text file from the PLGRGPS 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 processed navigation file can be accessed from within the nav folder or by clicking the following link: 03cch01.csv (762-KBCSV file). The file contains 12 fields that are defined as follows:

Field 1: LATITUDE - estimated latitude (decimal degree) positions of photographsField 2: LONGITUDE - estimated longitude (decimal degree) positions of photographsField 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 slideField 6: CONTACT_SHEET_URL - Web location of the contact sheet			Field 7: YEAR - year the photo was takenField 8: MONTH - month the photo was takenField 9: DAY - day the photo was takenField 10: PRE_POST - type of survey conducted (post-storm)Field 11: STORM - name of the stormField 12: GEO_AREA - locations surveyed

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### Raw Navigation

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-KBASCII text file), 03cch01_0322plgr.txt (20-KBASCII text file), 03cch01_0323plgr.txt (25-KBASCII text file). The file contains 10 fields separated by a space that are defined as follows:

Field 1: NUMBER - sequential numberField 2: WAYPOINT NUMBER - waypoint sequential numberField 3: LATITUDE - latitude (decimal degree) positions of photographsField 4: LATITUDE - latitude (degree minute second) positions of photographsField 5: LONGITUDE - longitude (decimal degree) positions of photographsField 6: LONGITUDE - longitude (degree minute second) positions of photographsField 7: ALTITUDE - altitude in feetField 8: DATUM - WGS84Field 9: ID NUMBER - year the survey was conductedField 10: PROJECTION - latitude/longitude - degree minute second

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### Manually Extracted Navigation

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-KBCSV file). The file contains eight fields separated by a space and defined as follows:

Field 1: LATITUDE - latitude (degree and decimal minutes) positions of photographsField 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 photographsField 5: HR:MIN:SEC - hour:minute:second (UTC)Field 6: YEAR - year the survey was conductedField 7: MONTH - month the survey was conductedField 8: DAY - day(s) the the survey was conducted

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#### Home | Acronyms | Contents | Navigation | Photos and Maps | Logs | Metadata

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U.S. Department of the Interior |            U.S. Geological Survey                                                URL: http://pubs.usgs.gov/ds/761/pubs761/html/nav.html            Page Contact Information: GS Pubs Web Contact                        Page Last Modified: Thursday, April 11, 2013, 10:05:31 AM