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Data visualization
Published in Benjamin S. Baumer, Daniel T. Kaplan, Nicholas J. Horton, Modern Data Science with R, 2021
Benjamin S. Baumer, Daniel T. Kaplan, Nicholas J. Horton
Clearly, we are using a geographic coordinate system here, with latitude and longitude on the vertical and horizontal axes, respectively. (This plot is not projected: More information about projection systems is provided in Chapter 17.) Shade is once again being used to represent the quantity population, but here the scale is more complicated. The ten shades of blue have been mapped to the deciles of the census tract populations, and since the distribution of population across these tracts is right-skewed, each shade does not correspond to a range of people of the same width, but rather to the same number of tracts that have a population in that range. Helpful context is provided by the title, subtitle, and legend.
Geodesy
Published in Basudeb Bhatta, Global Navigation Satellite Systems, 2021
In mathematics and applications, a coordinate (or referential) system is a system for assigning a tuple (ordered list) of numbers to each point in an n-dimensional space. Coordinate systems are used to identify locations on a graph or grid (Gaposchkin and Kołaczek 1981). For example, the system of assigning longitude and latitude to geographical locations is a coordinate system. There are various coordinate systems available to represent the location of any point. However, all of them fall into two broad categories—curvilinear and rectangular. Curvilinear system uses angular measurements from the origin to describe one’s position, whereas rectangular coordinate system uses distance measurements from the origin. One example of a curvilinear system is the geographic coordinate system that uses angular latitude/longitude measurements, and one example of rectangular coordinate system is the Cartesian co-ordinate system that uses linear measurements.
Trajectory Planning in Autonomous Vehicles using GPS and Digital Compass
Published in P. C. Thomas, Vishal John Mathai, Geevarghese Titus, Emerging Technologies for Sustainability, 2020
The geographic coordinate system with the latitude and longitude is similar to a graph with the x & y axis. The x axis represents the longitudes and the y axis represents the latitude. The 0-degree longitude also known as the Prime meridian becomes the origin on the x axis, similarly 0-degree latitude also known as the Equator becomes the origin on the y axis. Point on the y axis, above and below the x axis will be positive and negative respectively. Similarly points on the x axis, to the right and left of the y axis will be positive and negative respectively. In short the value of North and East coordinates will be positive while that of the South and West coordinates will be negative. Points on this virtual graph represent the position of the vehicle and the waypoints. Two points are considered at a time, the current position point and the next destination/target position point. The objective is to move the vehicle from one coordinate to the other, for accomplishing this objective; the system needs to know the direction the vehicle is pointing and the required direction of travel.
Template-based knowledge reuse method for generating high-speed railway virtual construction scenes
Published in International Journal of Digital Earth, 2023
Heng Zhang, Wen Zhao, Zujie Han, Jun Zhu, Qing Zhu, Xinwen Ning, Dengke Fan, Hua Wang, Fengpin Jia, Wei Fang, Bin Yang, Weilian Li
First, the models of the main project are reassembled in the geographic coordinate system, as shown in Figure 3. To solve the problem of inaccuracy in the process of transformation between multiple coordinate systems, transformation methods at different levels are used: the object level, the vertex level, and the vertex interpolation level. The transformation method at the object level converts the coordinates of a 3D model as a point, the transformation method at the vertex level converts the coordinates of the vertexes of a 3D model one by one, and the transformation method at the interpolation level converts the coordinates of the lines of a 3D model by vertex interpolation. With these transformation methods at multiple levels, line position data of the high-speed railway in the local or projection coordinate system is transformed into a 3D centerline in the geographic coordinate system. In this manner, the mileage coordinates are converted into spatial coordinates so that the 3D models of the railway are reassembled in the geographic coordinate system.
A method of heading estimation for pedestrian navigation based on information compression MDL criteria
Published in International Journal of Computers and Applications, 2020
Cheng-Yu Fei, Zhong Su, Qing Li
In the formula, S is the length of one step, φ is the body’s azimuth angle. In addition, the diagram also shows the system heading angle ψ at the foot. φ is applied in dead reckoning, which indicates direction of pedestrians’ step length in the two-dimensional space; ψ indicates the heading angle of carrier/device, and its schematic diagram as shown in Figure 2; E and N indicate the east and north of geographic coordinate system; xb and yb indicate the carrier (foot) coordinate system. After measuring the one-step information, it can be considered that there is an error in the azimuth, and the error range is related to the change of φ. Sampling can get the azimuth of each norm :
Deployment optimization for camera network coupling with geographic environment
Published in Annals of GIS, 2018
Ziran Wang, Meizhen Wang, Xuejun Liu, Yanan Zhang
The camera is a directional sensor, whose coverage is mainly decided by parameters such as location, height, the camera’s inner parameters and its gestures. The camera model described in this paper is shown in Figure 1(a), which is expressed as a tuple ; in this tuple, is the position of the camera’s optical centre in the geographic coordinate system; are, respectively, the azimuth angle and the pitch angle. The azimuth angle is the vertical angle between the north direction line of a particular point and the target direction line in the clockwise direction. The pitch angle is the horizontal angle between the vertical direction line of a particular point and the target direction line in the clockwise direction. are respectively the width, height and focal length of the imaging chip. The quadrilateral in grey in Figure 1(a) is the theoretical coverage of the current camera, which is projected from the pyramid formed by C-D1D2D3D4 to the ground.