Abstract: The present invention utilizes a novel polar coordinate grid to improve the processes of calculating and generating isochrones. Isochrones are lines on a map connecting places of equal travel time from a particular departure point. Calculating accurate isochrones is time consuming especially for large maps, because of the large number of data points to be processed. Data sampling is used to expedite the generation of isochrones, while maintaining acceptable accuracy. The present invention uses polar coordinate grid sampling for data sampling. Advantageously, polar coordinate grids have higher granularity at the center of a mapped region and lower granularity in regions farther away from the center in radial direction. Polar coordinate sampling reduces the amount of memory used and decreases the isochrone calculation time without perceptible degradation in isochrone accuracy.

Abstract: A method and system for controlling the execution of an application program to effect the performing of a specialized task is provided. In preferred embodiments, an interface computer program gathers status information from the application computer program, collects user input relating to the specialized task, generates commands to send to the application program, and sends the commands to the application program to effect the execution of the specialized task. The interface computer program communicates with the application computer program preferably through the dynamic data exchange of Windows.

Abstract: A divided table cell is generated by selecting one cell in a table and creating a new cell to display over the selected cell. Both cells contain a constraint that define an area where that cell cannot display objects. Objects comprise alphanumeric characters, graphical symbols or any representation in a table cell. The cells are displayed over top of each other such that the display area of one cell coincides with the constraint area of the other cell. The display shows a divided cell capable of accepting and editing objects. The divided cell also retains the characteristics of other cells in the table. The object layout in a cell with a constraint utilizes test rectangles to calculate the height and width of the displayable area of the cell. An initial test rectangle is calculated using the full width of the cell and the height of the objects to be placed in it.