‘y well 
nks to 
ther 
of 
id 
ill 
Maghed Marghany 
OPERATIONALIZATION OF SAR POLARIZED DATA FOR ASSESSMENT OF COASTAL EROSION 
Maged Marghany and Tjeerd W. Hobma 
International Institute For Aerospace Survey 
and Earth Science (ITC) 
Division of Applied Geomorphological Surveys 
PO Box 6 
7500 AA Enschede 
The Netherlands 
maged G itc.nl 
hobma@itc.nl 
Keywords: Operationalization, Polarised SAR data, Coastal erosion, Canny algorithm. 
ABSTRACT 
This study introduces a new approach for operationalization of SAR polarized data on coastal 
erosion studies. Polarized TOPSAR and ERS-1 data are used for this purpose. ERS-1 data was 
acquired on the 8^ August 1993 and polarized TOPSAR data was acquired on the 6^ December 
1996. A quasi-linear model and a new model based on the Canny algorithm were used to model 
shoreline changes. Digitized vector layers of shoreline change were used to examine the accuracy 
of the model results. This study shows that the results of the Canny algorithm has a good correlation 
with the results from the quasi-linear model. The Canny algorithm can successfully be used for 
automatic detection of shoreline change. In conclusion, the integration between the quasi-linear 
model and the Canny algorithm model enables further operationalization of SAR data for coastal 
erosion studies. 
1.0 INTRODUCTION 
Coastal erosion studies from ‘space are still in an early stage. Most studies that have been done by 
using remotely sensed data are restricted to the application of classical methods of shoreline 
identification based on digitizing and overlaying methods. These methods induce high rates of error 
and require a lot of time to process the data. In this process, the sum of thematic errors and 
digitizing errors account for the low accuracy of the interpretation results. This often results in 
inadequate solutions of the problems for coastal engineers and decision makers. For instance, Raj 
(1982); Mazlan et al., (1989), and Frighy et al., (1994) used different historical data of satellite 
imagery, aerial photography and topographic maps for coastal erosion studies. Most of these 
Studies found an unrealistic high rate of erosion of more than 50 m/year. For instance, Frighy et al., 
(1995) found the rate of erosion in the Nile Delta to be —70.8 m/year. However, if this rate really 
had occurred, it would have caused the destruction of all the infrastructures, such as roads and 
bridges near the coastal waters. Furthermore, Frighy et al., (1995) stated that there is a significant 
relation between shoreline change, estimated from Landsat TM, aerial photography and ground 
Surveys with a correlation coefficient (r) of 0.93. This can not be considered as a significant result, 
due to the fact that a significant statistical test such as ANOVA or the t-test have not been 
performed. In addition, the low resolution of the Landsat data (30 m) only justifies its use in coastal 
érosion studies with changes that are larger than this pixel size. As a matter of fact, the resolution of 
this sensor is unable to capture beach profiles at a width less than the pixel size (< 30m). The high 
resolution of SPOT PAN (10 m) and radar data such as from ERS-1 (12.5 m), Radarsat (12.5 m) 
and AIRSAR/TOPSAR (ca. 10 m) enables us to solve this type of problem. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B1. Amsterdam 2000. 201