Visualization of Spatial Constraint Databases
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Visual Thinking
used in the area of Human Computer Interaction (HCI). In HCI, the amount of visual momentum supported by a display system is inversely proportional to the mental effort required to integrate a new display into the context of the overall information space and the user’s information needs. Cross References Information Presentation, Dynamic
display the triangle on a computer through above process in three steps. ABC(x, y)
: − x ≥ 1, y ≥ 1, x + y < 4 .
First, convert the three linear inequality constraints in the tuple into three linear equations as follows: x=1 y=1 x+y= 4.
Visual Thinking Exploratory Visualization
Visualization of Constraint Databases Visualization of Spatial Constraint Databases
Visualization of Spatial Constraint Databases S HASHA W U Department of Math, Physics, and Computer Science, Spring Arbor University, Spring Arbor, MI, USA Synonyms Visualization of constraint databases; Visualization of spatiotemporal constraint data; Static displays in constraint databases Definition The visualization of spatial constraint databases is an application that reads spatial data from spatial constraint databases, understands the meaning of the data based on the spatial data models, and displays those data as computer graphics to help cognition, analyzing and reasoning.
Second, compute the set of intersection points for each pair of equations. Remove any points that do not satisfy the inequality constraints in the original tuple so that only the corner points of the polygon will be kept in the set. Order the resulting corner points in a sequence so that each pair of adjacent points represent an edge of the polygon. For example, the output point sequence for above problem is ((1,1), (1,3), (3,1)). Finally, call the operating system’s polygon function to draw the triangle based on the resulting sequence of corner points as well as the color assigned to relation ABC. The above general visualization process was implemented in most constraint database systems to display 2-D spatial constraint data. It was also used to animate 2-D spatiotemporal constraint data. Theoretically, it can be applied to visualize 3-D or higher dimensional data for constraint databases. Cross References Constraint Database Queries Constraint Databases and Data Interpolation Constraint Databases and Moving Objects Constraint Databases, Spatial Linear Versus Polynomial Constraint Databases MLPQ Spatial Constraint Database System Raster Data Vector Data
References Main Text To display the spatial data in a constraint database system, the system will first transform the vector-based spatial data, which is represented by linear equality and linear inequality constraints in a disjunctive normal form (DNF), into a set of points, segments, and convex polygons, then associate a color with the individual shapes and project them onto the output devices. For example, the following constraint tuple represents a triangle. The visualization of spatial constraint databases can
1. Revesz, P.: Introduction to Con
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