GeoISEM Home

Jockey's Home

Results

• LIDAR data processing
• Topographic analysis
• Measuring the change
• Photo gallery

Jockey's Ridge is loosing its elevation, migrating S/SW and expanding its area
(at its southern edge beyond the park and sand needs to be trucked back into the park - see photos).
Data: 1974 and 1995: photogrammetry, 1999: USGS/NOAA ATM LIDAR and 2001: NC Flood mapping LIDAR

Year                 1950   1974   1995   1999   2001   2002  2004  2007  2008
------------------------------------------------------------------------------
peak elevation [m]    43     34     27    25.7   24.8   23.6  21.9   21    22
area z>6m [acre]      NA     96    109     NA   106     NA    NA

Space-Time Cube analysis Evolution of countours 15-26 with 1m step, time period 1974-2008 Change 2008 and 2007

Elevation change: 2007-2001 bare earth, 2008-1999 incl. vegetation
DEMs 1974-2008
Crests: 2001, 2007, 2008

Overlayed 1999(grey) and 2007(colored)
profile 1 profile 2 profile 3 profile 4

Overlayed elevation surfaces:

1974 (brown) and 1995 (orange):
East view SE view

1995 (orange) and 1999 (red, with vegetation):
East view SE view

1999 (red) and 2001 (yellow):
East view SE view

2001 (yellow) and 2004 (green):
East view SE view

Time series of DEMs representing evolution of Jockey's Ridge sand dune 1974-2001:

1974 1995 1999 2001 2004

DEMs with change draped over the surface (blue is deposition, red-yellow is erosion, see the legend below)

1974-95 1995-99 1999-01 2001-2004

Migration of the dune represented by relocation of the 18ft contour (see Overlay of the 18ft contour and slip face slopes):
Contour z=18ft for the years: 1974|| 1995|| 2001|| Download as shape files here
Contours overlayed in a single image
1974(brown),95(orange),01(red)

Change in the horizontal location of 18ft contour: red is erosion, blue is deposition
1974-95 1974-95

Note: the 1999 LIDAR surface includes vegetation,
the 2001 LIDAR DEM has the vegetation and homes removed
- they show as a loss, mostly colored in green

Moving features

All ridges 1974-2001
All ridges 1974-2001

We used 2002 Real Time Kinematic Surveys of the dune's critical areas
to assess its change between 1999-2002 (done before we got the 2001 LIDAR):

• Table showing the horizontal and vertical dune movement between 1999 and 2002

• LIDAR-based 1m resolution DEM, with IR-DOQQ draped over it and red dots representing the path of
  Real time kinematic survey January 2002
• LIDAR-based 1m resolution DEM, with IR-DOQQ draped over it. Red and white dots represent the path of
  Real time kinematic survey January 2002 and April 2002
• IR-DOQQ based 1998 land cover with January 2002 (bright red) and April 2002 survey (pink) showing
  the movement of dune into vegetated areas.
• Detail 1: South dune moving towards the road and homes
• Detail 1: Vertical profile (view from south)
• Detail 1: Profile curvature overlayed with RTK-GPS
• Detail 2: East dune moving towards the road at 20m per year
• Detail 3: Main ridge, the crest moving 20-40m per year to south, the top lost 2m over past 3 years
• Detail 3: Profile curvature overlayed with RTK-GPS
• Detail 4: Lower central area is growing, white points represent April 2002 survey