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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
The second row figures show a similar cross section of surface
but indicate the relative location of both first and second order
of momentums to be used in direction finding procedure. It is
obvious that both orders points in the normal shape are
coincident while there is a displacement of both of them in the
inclined and affected state. The vector connecting first to
second order point introduces the inclination direction of
wave's peak in a 3 dimensional space. Portraying this vector on
the X-Y plane gives the direction of the current in the local
coordinate system, which will be transferred in the specific
coordinate system for further use. Here are the equations to
compute the first and second order surface momentum having
the coordinates of points Eq3.
em
ym d
Wired Direc Lun 3
Figure 3. a) First order of surface momentum point of resulted
surface of a normal wave in a cross section of a plane
perpendicular to the X-Y plane (Most top). b) Distance vector
between surface points and First order of surface momentum
point of resulted surface of a deformed wave in a cross section
of a plane perpendicular to the X-Y plane (Top). c) Second
order of surface momentum point of resulted surface of a
normal wave in a cross section of a plane perpendicular to the
X-Y plane (Lower). d) First and Second order of surface
momentum point of resulted surface of a deformed wave in a
cross section of a plane perpendicular to the X-Y plane
(bottom).
G)
Where r(i) Distance between the first momentum and
surface Points
O(k) First surface momentum point of kth maximum
point
O’(k) Second surface momentum point of kth
maximum point
P(i) The ith point of surface peak
The second order surface momentum inclines toward the
sharpness tip of a deformed shape. Finally to get a better and
more reliable result out of this method, the surface model can be
accompanied with the bathymetric models of the area.
3. THE DATA USED AND RESULTS
The method described above must be applied on a dataset in
order to see its impact and results in a real case. For some
reasons the TerraSAR-X dataset was not accessible and we were
obliged to use another satellite data. The data used in this paper
is from Jason] satellite altimeter and was taken from the NOAA
(4| website. Hope to use the TerraSAR-X data in the future
works. The Surface model is determined using the Delaunay
triangulation method. This surface has been used in our method
and the results which were in the local datum have been
transferred in to the UTM system. For better demonstration and
use of dataset results, the vector field has been exported in the
KML format to be shown in the Google Earth Environment.
The location of data set is over the Hormuz strait connecting
The Persian Gulf and The Oman Sea. Vector field over the
Hormuz Strait is shown in the Figures (4, 5 and 6).
Figure 4. Surface current vector field Over the Coastal area of
Hormuz Strait in an overall view and low resolution but high
density.
Figure 5. Surface current vector field Over the Coastal area of
Hormuz Strait in detailed view and high resolution and vector
density.