|
Methods
involved in preparing the maps
The method involves the following steps
1. Preparation of base maps using topographic sheets and also also in
consultation with tide charts.
2. Demarcation of low tide coastal landforms from aerial photographs using
tone and texture variations.
3. Extensive field verifications of landforms during low tide and generation
of thematic maps.
4. Digital conversion of base maps and derived thematic maps .
(a) Digitization (scan to raster and convert to vector or trace the maps
using a digitizer table)
(b) Error removal, feature labeling and attribute indexing
5. Transect surveys
were determined across these landforms to study their fauna/flora distribution.
6. The results of the transect survey were organized in spread sheets.
7. The transect survey results( spread sheets) linked with maps using
common attributes.
8. Developing a Geographic
Information System (GIS) database by integrating the thematic maps
and the survey results.
Some of the maps in this study were prepared using Global
Positioning System (GPS)
In this system the device uses triangulation method to calculate the real
time position using measure distance through radio signal from satellites.
This system is quite expensive but very accurate. GPS system found to
be very useful and also helpful in preparing accurate intertidal maps.
Advantages of Intertidal maps
- The maps can show the overall distribution of habitats over large
areas of shoreline and can be invaluable
- Entering field data directly to a PC has several advantages. As well
as being quick, it cuts out sources of error which can be created by
in-between paper stages.
- The maps can highlight and help quantify large-scale changes in habitat,
fauna/flora distribution.
- Data stored in a GIS are more flexible and can be interrogated
|
