A case study of El Salvador City has been done using various photogrammetric techniques. This project comprised the complete new mapping of the town including all features like buildings, boulevards, roads,manhole/ drainage, light / telephone polls, trees /tree areas, ponds, river and streams (with break lines), Monuments, playground / Parks etc. The vectorization of the model has been done on Digital (Socket Set) and analytical systems both. From speed point of views digital systems are as good as analytical systems. It also depends on the skills / expertise of the Operator who is preparing the maps.
HP announces expansion of Designjet
HP has expanded its Designjet largeformat portfolio with a range of new workgroup and multifunction printers, software solutions and new media choices to address the needs of vertical segments, IT managers and production operators. The new products, solutions and large-format papers are ideal for GIS, architecture, engineering and construction (AEC) and mechanical computer aided design (MCAD) workgroups. www.hp.com
As India launches the DSMs and OSMs under its new map policy, it should not let the opportunity …
The National Informatics Centre, Government of India is organizing NSDI-V during December 18- 21, 2005 at Hyderabad, India. On the occasion we present here the excerpts of recommendations of last four NSDI conferences. They, with the subsequent interviews, reveal moments of euphoria and despair, issues discussed and debated, and more importantly a resolve to pursue this dream.
Users of positioning and spatial information services and tools require precise spatial information in realtime and real-world objects. Simply an accurate positioning of a future subdivision is no longer accepted, users require it to be visualized as well, in order to take into account outside in?uences. The capacity to meet such user needs and deliver services and tools within the spatial information market has gone beyond the ability of single organisations (Rajabifard, et al, 2005a). There is now a wide range of products and services available for a wide range of IT applications, and hence the development of an enabling platform can facilitate access to data and sharing resources and tools among different practitioners. The creation of an enabling platform for the delivery of these tools and positioning applications will allow users from diverse backgrounds to work together with current technologies to meet the dynamic market place.
China joins Galileo spacebased application projects
A Chinese general contractor for the European Galileo Project in Beijing recently obtained three space-based application projects. The Galileo Joint Undertaking (GJU) endorsed the China Galileo Industries (CGI) to develop search and rescue radar transponders (SART), laser retrore ?ectors and up-link stations (ULS). Meanwhile, the Early Galileo Services in China (EGSIC) and the Galileo Olympic Games Demonstration (GOGD) are also open for public bidding. China was the first country outside Europe to join the Galileo Project, agreeing to invest a total of 200 million euros into the global consortium. About 70 million euros of the Chinese investment have been put into technologies development and the remaining 130 million euros into deployment of space and ground infrastructure.
http://english.people.com.cn
Interest in the use of Global Navigation Satellite Systems (GNSS) as a main source of navigation reference is increasing. The system employed for such a purpose should be capable of meeting the requirements of air navigation in terms of accuracy, availability, integrity, and reliability. At present, the accuracy requirements for all ?ight categories up to precision approach are summarized in Table 1. The accuracy requirement for Category I can be achieved most of the time using wide area differential systems such as the American “WAAS”, the European “EGNOS”, and the Japanese “MSAS”. The American Federal Aviation Authority (FAA) is developing a Local Area Augmentation System (LAAS) for categories II and III, involving the ?nal and precision approach phases of ?ight. The system includes at least four reference GPS receivers located at each airport, whereby GPS measurements are collected and processed in real time. The computed GPS differential corrections are sent to aircraft via a (VHF) radio link to calculate its location. LAAS preliminary test results have generally demonstrated accuracy of less than 1 meter. However, the percentage of system availability is still under evaluation. The cost of establishing LAAS for major airports is expected to be significant.
1. Spheroid is considered equivalent to an ellipsoid.
2. The longitude at the North or South Pole is zero degree.
3. The Mean Sea Level (MSL), a time-variant “average”, is
considered as time-invariant and time-independent.
4. The measured “dn” along a spirit level loop sum up to zero.
5. Imagine a freely ?owing ocean or sea channel under
a continent and it represents the Geoid.
6. The geoidal undulation or height (N) is equivalent to orthometric height (H).
7. There are “yours” and “mine” geoids. In other words every country has its
own geoid, creating a “political” boundary value problem for gravity.
8. When one has to re-observe at any station, it does not make any
difference so long one is observing within “few” meters.
9. If one asks for and gets a height as “123.4 m”. It is OK to add
zeros at the end, e.g., 123.4000, to make it more accurate.
A report on ION GNSS 2005, 13-16 September, Long Beach, USA
Recent …
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