This application and special course is focussing on the use of bathymetric information, collected over a lake / reservoir and how to integrate this information with observations and those from altimeters. Use is made of Shuttle Radar Topographic Mission data (at 1 arc-sec resolution) to derive initial lake extent which is compared to satellite observations during SRTM data acquisition.
The exercise is composed of various components. Firstly the altimeter data collected over the lake / reservoir is reviewed, subsequently the SRTM derived elevation model is processed and the lake level mask is extracted. This mask is compared to a modified normalized water index (MNDWI) map derived from satellite image acquired at about the same time of collection of the SRTM DEM.
Subsequently the bathymetric observations are processed, incorporating the water body extent of the extracted MNDWI map. The interpolated bathymetric information is integrated into the SRTM DEM and various lake extent maps for different water levels are computed.
Once the extent maps are available these are transformed into water body depth maps and allowing the calculation of statistics, like area, depth versus volume. A regression analysis allows linking the volume(s) calculated to the altimeter observations. Subsequently the time series of altimeter observations can be transformed into lake / reservoir volumes.
Geographic Information System (GIS) helps to manage spatial and non-spatial information in a very efficient way. Properly managed data and information helps in better territorial planning and decision making. In GIS, data about real-world objects is drawn quickly and can be displayed using the different attribute fields stored in GIS databases. The sources for spatial data can be from different sources including Field observation / measurement, GPS based data collection, Remote sensing and software based derivations like map digitization. Currently Satellite based data acquisition is providing continues image products for almost all areas of the world at different spatial resolutions. Remote sensing is a valuable data source to obtain information about the surface of the Earth. Several platforms have been historically used to collect data, starting from kites to balloons, airplanes, satellites and very recently, unmanned aerial vehicles. The applications of remotely sensed data are extremely broad, and it is increasing exponentially due to recent improvements in data resolution and availability. Drought is an insidious natural hazard that results from lower levels of precipitation than what is considered normal. When this phenomenon extends over a season or a longer period of time, precipitation is insufficient to meet the demands of human activities and the environment. Monitoring this phenomenon is has a paramount importance. Flood hazard assessment can be conducted in various ways depending on the data availability. The method of carrying out the assessment depends on the information, technology and resources available.
Disaster Risk Management, as a process can be seen from different points of views; some of these include processes from the hazard, disaster governance, and disaster cycle points of views.
This course is consisting of 4 components:
- Introduction to GIS and Remote Sensing
- Application of GIS for Drought Assessment
- Application of GIS for Flood Assessment
- Use of GIS techniques for Disaster Risk Management