Map annotation is an important information representation method in computer-aided cartography and GIS. It is a
supplement for map symbol system. With the development of computer technology, the Automatic Placemen of
Annotation for map becomes a hotspot subject in computer-aided cartography. Usually, map Annotation is divided into
three kinds: point feature, line feature and area feature. Specifically, the Placement of Annotation in Area Feature has
being discussed by some scholars and many kinds of algorithms are given, mainly referring to the angle of the Annotation Placement. This paper discusses the Placement of Annotation in Area Feature within a point of view of the spatial geometric structure of the map, gives a new algorithm based on Map Spatial Geometry Information Measurement to complete the placement of annotation and compares the research results with the others.
Two dynamic characteristics, on-line map update and real time traffic information, are currently considered as the most
important feature of vehicle navigation system. Therefore, the need of incorporating dynamic information into vehicle
navigation system should be emphasized because the lack of data representation to integrate navigation data with models
for spatio-temporal processes appears to be a major shortcoming in traditional vehicle navigation system. Consequently,
in this paper we briefly summarize spatial and temporal characteristics of the DVNS (Dynamic Vehicle Navigation
System). And then, based on these summaries, we propose a data model with spatio-temporal characteristic instead of
static data model. In this data model, spatial feature, temporal feature and traffic feature are all integrated into a unified
data model in order to supporting dynamic route plan and on-line map update in the DVNS. Finally, a prototype system
based on the proposed data model is tested and implemented.
This paper presents an off-line traffic prohibition sign detection approach, whose core is based on combination with the color feature of traffic prohibition signs, shape feature and degree of circularity. Matlab-Image-processing toolbox is used for this purpose. In order to reduce the computational cost, a pre-processing of the image is applied before the core. Then, we employ the obvious redness attribute of prohibition signs to coarsely eliminate the non-redness image in the input data. Again, a edge-detection operator, Canny edge detector, is applied to extract the potential edge. Finally, Degree of circularity is used to verdict the traffic prohibition sign. Experimental results show that our systems offer satisfactory performance.
The acquisition of the spatial data is a fundamental problem in multi-dimensional and dynamic GIS construction and infrastructure. Ground-based mobile Laser scanning System, which is mainly used in the reconstruction of 3D city and acquisition of local region geographic information, has an important function in rebuilding 3D spatial object. This integrated systems have the same sensors GPS/INS for positioning. In this paper, our researches are focused on multi-sensor integration without GPS/DGPS/INS. The application system we developed is a ground-based motive platform, upon which multi-sensors were integrated. In system, a relative positioning sensor we employed is the Rotary Encoder, which determines the relative positions of the platform from original position and the Laser Scanner’s posture. The Laser Scanner surveys the distances between the platform and the object. All data were transferred through wireless cable into the server located in the office. The wireless modem we applied provides reliable wireless data communication for either point-to-point or multipoint applications. In this paper the outline of system, principles and algorithm are presented. Moreover, some trials and experiences are presented in this paper. Finally some conclusions and further research work are introduced.