Robust Extraction of Shoreline by Integrating Robust Extraction of Shoreline by Integrating DubaiSat1 Multispectral Imagery and a DubaiSat1 Multispectral Imagery and a

Coastal Terrain Model (CTM)Coastal Terrain Model (CTM)

Tarig A. Ali, PhDAssociate Professor, Dept. of Civil Engineering

American University of Sharjah, UAE

Geospatial World Forum - Rotterdam, Netherlands

May 13-16, 2013

Flow Chart of Technical Approach

Study Area: Al-Ras area, Dubai, UAE

DubaiSat1 Image of the study area

•Multispectral (R, G, B) •Spatial Resolution: 5m•Acquisition date: 12 Nov, 2011

•Image was enhanced by applying a median filter followed by a HPF “basic: -1s and 8”. • Advantages of the median LPF: preserves edges while removing impulse noise and yet help to avoid excessive smoothing.

Surface-Leaving Radiance in the Red Band of DubaiSat1 Image

Note the high absorption in the red region of the electromagnetic spectrum of the Image

Classification of DubaiSat1 image

• The Iterative Self-Organizing Data Analysis Technique Algorithm (ISODATA) was used in the classification.

Geospatial World Forum - Rotterdam, Netherlands

May 13-16, 2013

Classification techniques

• ISODATA algorithm takes maximum advantage of spectral variability in an image.– “Iterative Self-Organizing Data Analysis

Technique”• Parameters :

– N - the maximum number of clusters that you want– T - a convergence threshold and– M - the maximum number of iterations to be

performed.

Geospatial World Forum - Rotterdam, Netherlands

May 13-16, 2013

MS image-derived Shoreline segment

Data used to create the CTM of the study area

• The data set comprised of:– 3D bare earth mass points – bathymetric contour data: 10-m interval

(surveyed in late September 2011). • LIDAR acquisition date: week of 20

November, 2011 • LiDAR system: Leica LS-50 system

integrated with IMU & GPS. • Positional accuracy: RMSE = 0.23-m. • Vertical accuracy: RMSE = 0.10-m in open

areas. • Spatial Reference: Dubai Local Transverse

Mercator (DLTM) - WGS_84.

Flowchart of Building a CTM using ESRI’s TDS

Costal Terrain Model (CTM) of the study area

Spatial Resolution: 10m

Fusion of the MS Image based Shoreline, CTM, and Aerial Image

Outcome: Refined shoreline

Concluding Remarks

• Extraction of shoreline by fusing DubaiSat1 MS imagery, DTM, and an aerial image was successful .

• Issues need further investigation:– Effect of the difference in spatial resolution

between the MS image and the DTM– Effect of the vectorization of the shoreline derived

from DubaiSat1 MS imagery.

Geospatial World Forum - Rotterdam, Netherlands

May 13-16, 2013

Thank youThank you