Automatic Approach for Assessing forest Disasters Utilizing Simulated High Resolution Satellite Imagery
(ii) Forest data sets
The forest planning maps at 1:5,000 scales corresponding to one unit of 4 ha (200m X 200m) were digitized showing the damaged forest administrative boundaries and register book information were entered, linked and stored in the FDAS.
(iii) Concept of the FDAS
Figure 2. Concept of the Forest Disaster Assessment System (FDAS)
The conceptual diagram is shown in Figure 2. The low cost GIS software package utilizing high-resolution images for automated mapping, analysis and reporting are the concepts of this system. The damaged areas are extracted from high-resolution satellite image after the disaster and the data on forest register and damaged areas are entered to the system. The predetermined information an damaged areas are automatically calculated for report preparation. The system enables forest managers to easily integrate and use available tabular and map information source to make better decisions.
(iv) Extraction of the information on damaged areas
The satellite images, before and after the disaster, are superimposed for two different seasons and detection of the affected area is extracted by image classification using image processing software by spectral signature similarity (correlation analysis) (Inamura et al., 1982 and Yasuoka et al., 1988). The images are classified for the information and soil situation, fallen trees, eroded area (due to the landslide) etc. the classified images are compared for correlation analysis and brightness comparison is preformed. Depending upon the analysis result, for extracted information on damaged areas, the most suitable analysis technique is adopted.
Result and discussion
(i) Functions of FDAS
The basis and function of FDAS is shown in Figure 3. The system is handled in Arc View Version 3 and operated on Windows 95 as a desktop version with ARC/INFO. FDAS has been developed using Visual Basic in conjunction with Arc View Version 3 and Microsoft Excel on Windows 95 or Windows NT.
Register
new
information on damage |
Display
damaged areas |
Measure
damaged areas |
Search
forest register
(automatic) |
Measure
landslide quantity |
Calculate
damage information (automatic) |
Report
preparation (automatic) |
|
ArcView Version 3 (Desk Top GIS) |
 |
Microsoft Excel |
| Window95 or WindowsNT |
Figure 3. Basic and Function of FDAS
Figure 4 shows the screen display of the system. When the system starts, a main window is always indicated on the top of the screen with menus and tool bars for assisting modules. The sub-menu indicates the function on various information about the forest damage depending on the menu selection (Figure 5). The map window displays map and image.
Figure.4 General screen display and main menus
Figure.5 Sub-menus for disaster type and location
