Optimizing surveying and mapping systems.

摘要

Surveying and Mapping systems are developing very fast mainly due to the advancement in space and computer technologies. Some user agencies of the surveying and mapping systems are adopting the advanced systems rather slowly. This is evident especially in the developing countries.; The Geographic Information System (GIS) plays a vital role in preparing the infrastructure for all the modern development works worldwide. The purpose of this thesis is to find an optimal GIS which uses and anticipates the modern techniques combining the traditional and modern systems.; Different aspects of Surveying and Mapping Systems such as datum transformations, map projections, accuracy standards, geodetic surveys, cadastral surveys, mapping from space, etc., act as the back bone for an optimal land related Geographic Information System. A thorough analysis of these aspects of Surveying and Mapping Systems are made to reveal the merits and defects of these systems.; Universal map accuracy standards are proposed for conventional as well as computer aided/geodetic mapping system. Several test computations were performed to obtain a model for converting ellipsoidal heights obtained from Global Positioning System (GPS) to the desired geoidal heights. The size of integration elements over the same area has a significant effect on the computation of geoid undulation. For example, a difference of 65.20 {dollar}pm{dollar} 0.68 centimeters in geoid undulation was obtained over the same 1{dollar}spcirc{dollar} x 1{dollar}spcirc{dollar} area when 30{dollar}spprime{dollar} x 30{dollar}spprime{dollar} and combination of 5{dollar}spprime{dollar} x 5{dollar}spprime{dollar} and 1{dollar}spprime{dollar} x 1{dollar}spprime{dollar} subdivision integration elements were used. An optimization model is developed based on three principles: (i) maximize the accuracy standards, (ii) minimize the cost of systems, and (iii) maximize the number of users of the output products. A general cost/benefit analysis model is developed and discussed with examples. Three different types such as Global, Regional, and Local Geographic Information Systems have been proposed.