The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity d...The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity degree/relation in multi-scale map spaces and then proposes a model for calculating the degree of spatial similarity between a point cloud at one scale and its gener- alized counterpart at another scale. After validation, the new model features 16 points with map scale change as the x coordinate and the degree of spatial similarity as the y coordinate. Finally, using an application for curve fitting, the model achieves an empirical formula that can calculate the degree of spatial similarity using map scale change as the sole independent variable, and vice versa. This formula can be used to automate algorithms for point feature generalization and to determine when to terminate them during the generalization.展开更多
Extracting the three-dimensional (3D) information including location and height of a pedestrian is important for vision-based intelligent traffic monitoring systems. This paper tackles the relationship between pixels...Extracting the three-dimensional (3D) information including location and height of a pedestrian is important for vision-based intelligent traffic monitoring systems. This paper tackles the relationship between pixels′ actual size and pixels′ spatial resolution through a new method named pixel-resolution mapping (P-RM). The proposed P-RM method derives the equations for pixels′ spatial resolutions (XY-direction) and object′s height (Z-direction) in the real world, while introducing new tilt angle and mounting height calibration methods that do not require special calibration patterns placed in the real world. Both controlled laboratory and actual world experiments were performed and reported. The tests on 3D mensuration using proposed P-RM method showed overall better than 98.7% accuracy in laboratory environments and better than 96% accuracy in real world pedestrian height estimations. The 3D reconstructed images for measured points were also determined with the proposed P-RM method which shows that the proposed method provides a general algorithm for 3D information extraction.展开更多
In 1748,Giambattista Nolli published a large map of Rome,which accurately depicted the form and system of public space in the city.This graphic presentation has become a powerful tool for urban space research.However,...In 1748,Giambattista Nolli published a large map of Rome,which accurately depicted the form and system of public space in the city.This graphic presentation has become a powerful tool for urban space research.However,given the increasingly abundant types of contemporary urban spaces and diverse functions of public buildings,the application of the drawing principle of the Nolli map to contemporary cities remains uncertain.Taking the Laochengnan area in Nanjing as an example,this study investigates the mapping of urban public spaces based on the Nolli map method.On the basis of a field survey,the public and private spaces in the blocks are identified.By comparing the graphic information of the Nolli map and that of the Nolli-type map in terms of public,private,and green spaces,this work also reveals the similarities and differences between traditional and modern urban spaces.Urban spatial mapping methods,including the figure-ground map,street map,and Nolli-type map,are explored and compared using complementary mapping techniques.The practicality and effectiveness of each technique are also discussed.Results show that the Nolli map method is effective in mapping contemporary urban public spaces and provides an effective tool for urban designers and architects to depict and analyze urban public spaces.展开更多
基金funded by the Natural Science Foundation Committee,China(41364001,41371435)
文摘The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity degree/relation in multi-scale map spaces and then proposes a model for calculating the degree of spatial similarity between a point cloud at one scale and its gener- alized counterpart at another scale. After validation, the new model features 16 points with map scale change as the x coordinate and the degree of spatial similarity as the y coordinate. Finally, using an application for curve fitting, the model achieves an empirical formula that can calculate the degree of spatial similarity using map scale change as the sole independent variable, and vice versa. This formula can be used to automate algorithms for point feature generalization and to determine when to terminate them during the generalization.
文摘Extracting the three-dimensional (3D) information including location and height of a pedestrian is important for vision-based intelligent traffic monitoring systems. This paper tackles the relationship between pixels′ actual size and pixels′ spatial resolution through a new method named pixel-resolution mapping (P-RM). The proposed P-RM method derives the equations for pixels′ spatial resolutions (XY-direction) and object′s height (Z-direction) in the real world, while introducing new tilt angle and mounting height calibration methods that do not require special calibration patterns placed in the real world. Both controlled laboratory and actual world experiments were performed and reported. The tests on 3D mensuration using proposed P-RM method showed overall better than 98.7% accuracy in laboratory environments and better than 96% accuracy in real world pedestrian height estimations. The 3D reconstructed images for measured points were also determined with the proposed P-RM method which shows that the proposed method provides a general algorithm for 3D information extraction.
基金The research on which this paper is based was funded by the National Natural Science Foundation of China(No.51538005 and No.51708274)the Nanjing University Doctoral Student Innovation and Creative Research Project(CXCY19-57).
文摘In 1748,Giambattista Nolli published a large map of Rome,which accurately depicted the form and system of public space in the city.This graphic presentation has become a powerful tool for urban space research.However,given the increasingly abundant types of contemporary urban spaces and diverse functions of public buildings,the application of the drawing principle of the Nolli map to contemporary cities remains uncertain.Taking the Laochengnan area in Nanjing as an example,this study investigates the mapping of urban public spaces based on the Nolli map method.On the basis of a field survey,the public and private spaces in the blocks are identified.By comparing the graphic information of the Nolli map and that of the Nolli-type map in terms of public,private,and green spaces,this work also reveals the similarities and differences between traditional and modern urban spaces.Urban spatial mapping methods,including the figure-ground map,street map,and Nolli-type map,are explored and compared using complementary mapping techniques.The practicality and effectiveness of each technique are also discussed.Results show that the Nolli map method is effective in mapping contemporary urban public spaces and provides an effective tool for urban designers and architects to depict and analyze urban public spaces.
