Modified Method for Drawing Geographic Maps by Using Cubic Spline Interpolation


This paper presents suggested modified algorithm to draw the geographic maps. Cubic spline interpolation had been used to draw these maps by generating intermediate points between each two points from a set of given points, where these intermediate points represent the control points which they are used to constrain the curvature of cubic spline depending on a value named divisor value that representsthe distance between any two adjacent points at spline knots, and specified by the user. Intermediate points have a great effect on curve shape, through dividing the interval between two adjacent points into equal subintervals. This makes the results of the weights ai, bi and ci in spline function will be equal to zero and di has already been determined to be di = yi , according the equations determining the weights,. So we can draw lines and polygons that are necessary in drawinggeographic maps.