Adoption and adaptation of digital photogrammetry in a Hong Kong survey practice

Abstract

There are many private land surveying practices existing in Hong Kong. The companies are mainly divided into two groups: concentrating in particular disciplines (cadastral, engineering or fitting out) or in a broad range of types of disciplines. Their competition for business is very high. It is a continuous challenge for the private practices keeping their businesses cost-effective. The manpower, equipment, measurement and data processing techniques applied to tasks are all expenses to the company, which must be offset against income with the aim of making a profit. The management should continually seek ways to achieve this. There are two major arenas that many land surveying companies explore to increase their profitability. First, new markets for providing their services; second, the adoption of new technologies. In the surveying industry, the two arenas do affect each other. This investigation responds to the above situation. Its aim is to introduce digital photogrammetric technology into a Hong Kong private surveying company to investigate the possibility of advancement in its services. There are two covered areas in the research. First, the technological considerations through an equipment and manpower study, and accuracy standard achievement of photogrammetric techniques compared with traditional surveying methods. Second, the economic considerations involving decision making processes, benefit-cost analysis and sensitivity analysis. The approaches set in the research can be divided into four areas. Firstly, the evaluation of the current technology, equipment and software. It is necessary to investigate their effect in the company's everyday fieldwork. According to the nature of different projects, conventional surveying methods and photogrammetric techniques have both pros and cons in different areas. Secondly, the establishment of working procedures. Through the practices involving manpower in the company, the crews can have guidance on basic knowledge in the introduced technology. Thus, a spread in learning photogrammetric techniques can form in the private sector. Thirdly, the development of a decision-making algorithm for the industry to investigate the profitability of the adoption of this technology. This analysis is to provide support to users in evaluating their decisions. The different methodologies are treated as different alternatives in the analysis. The well-known Analytical Hierarchy Process is selected as the tool in the benefit-cost analysis. After the development of several photogrammetric techniques both for independent application and in cooperation with conventional surveying methods, the partnering company started investigation on its tasks. Eventually, the exploitation of new opportunities with the aid of the company's photogrammetric field practices is needed. It is found that for the tasks of 3D visualization model establishment, photographic survey, and terrain modeling, digital photogrammetry show advantages over conventional survey techniques with acceptable costing in equipment and staff training. This conclusion was reached assuming that the photogrammetric systems were already available within the company. However, when their cost is included, only 3D visualization models and photographic survey applications were considered as being feasible. For the studied company, it was found that projects requiring 3D visualization model establishment could be economically undertaken by digital photogrammetric systems comprising of data acquisition devices such as higher resolution digital cameras (e.g. Fujifilm MX700 in this research) and software such as low-cost photogrammetric/modeling packages (e.g. PhotoModeler).