In continuation of the discussion about the ellipsoid and geoid in the earlier interaction through the Classroom feature, let us define the reference coordinate systems. Consider a vertical axis oriented towards the north pole as Z axis. The X axis is oriented towards the First point of Aries ?. The Y axis completes a right …

Terrified at what we saw through the electronic media; the agony and trauma that Mumbai underwent …

Maharashtra was the first state in the country to have a disaster management plan. It all started with the Latur Earthquake of 1993. As a part of response programme, the Maharashtra Emergency Earthquake Rehabilitation Project (MEERP) was launched the same year. This later led to the exercise of preparing a State Disaster Management Plan. The World Bank, United Nations Development Program (UNDP) as well as several bilateral donor agencies supported the initiative.

The 26th July 2005 floods in Mumbai, which caused widespread destruction, deaths and damage to property and infrastructure, have once again highlighted the importance of disaster mitigation and management using modern technology. Monitoring natural disasters like floods, earthquakes, volcanic eruptions, landslides, avalanches, cyclones, etc., with the ultimate aim of predicting them, and managing the rescue and rehabilitation operations during and after such calamities, have been discussed in various forums in the past. The devastating Latur earthquake of 1993, the Bhuj earthquake of 2001, the Orissa cyclone, and the recent tsunami after the Sumatra earthquake, which caused extensive damage in terms of human lives and property, have drawn the attention of the Indian scientific community to the immediate need of monitoring and managing such disasters in our country in the most effective, efficient and economic manner. Traditionally, maps are being used for this purpose, as an effective tool, since ancient times. However, with the introduction of computeraided techniques in map-making, and the space technology in surveying and mapping, the utility of geodetic and map data for this important activity has increased many-fold. However, a well-coordinated programme for optimum utilization of these important technological tools, resulting in efficient management of the disasters, still remains an elusive dream of administrators, scientists and technologists.

Engineering structures undergo deformation due to various kinds of static and dynamic loads. Thus, monitoring of structure, specifically large structures such as high-rise building, bridges, dams etc., is essential to ensure its safe deformation behavior. With multifold rise of traffic, to provide safety and to prevent disaster, it has become necessary to detect uncharacteristic deflections and vibrations of bridges. The instruments which are often used for measurement of defl ection such as
strain gauge, accelerometer, tiltmeter, vision system, optometer, laser gauge meter etc are often cumbersome as well as costly in implementation. Moreover, they suffer from one defi ciency or the other. Hence, there is a need for a method which is simple, economic yet provides accurate and reliable measurement.

In Today’s world, with GPS, we can survey ellipsoidal heights (h) with 5-10 cm accuracy for geodetic control points on land and differential heights (?h) between well defi ned topographic features with relative accuracy of 1: 1Million or better. In few specific cases, this type of accuracy may require specially designed GPS surveys. In navigational mode, an instantaneous positional accuracy of about ± 5 m is easily possible. As these heights are the direct product of the GPS survey(s) and thus defi ned with respect to the ellipsoid, which is a time-invariant zero reference surface, they can be used without any reference to the geoid or Mean Sea Level (MSL). If we recall, in the classical surveys, e.g., triangulations and/or traverses, the vertical angles used to provide the “?h” and thus there will not be any need to convert them to orthometric heights.

The environment of a Municipal Information system has undergone a sea change over last few years. Couple of years back the requirements of information system was designed and projected primarily from the planners community. They were satisfi ed if the physical information was supplied on a scale of 1:5000/ 1:10,000.

The 7th Asia Pacific ITS Conference & Exhibition was …

13,000 users attend ESRI’s 25th Annual User Conference

With nearly 13,000 users attending from more than 135 …

July 2005

IGARSS 2005

25 – 29 July 2005 Seoul, Korea

reg@igarss05.org

http://www.igarss05.org

25th Annual ESRI International …