5.2             Simplify Line

 

Simply Line is used to simplify a polyline by removing small fluctuations or extraneous bends from it while preserving its essential shape. This step becomes particularly crucial for quality and efficient domain decomposition as an unsimplified feature can have unnecessarily large number of nodes in it which in turn determines the number of triangulations generated. Needless to say, larger is the number of decomposed triangle elements, larger will be the computational requirement of the numerical model simulation. Figure x.x shows intermediate steps in polyline simplification using Douglas-Peucker algorithm.

 

Original Polyline

Simplified Polyline

Maximal Distance Line

Distance Line Smaller Than Threshold

 

First of all browse shape file(s) of “polyline” type. A tolerance (double type) should be provided which acts as the maximum distance value for the simplification algorithm. After that + button allows to add the file and the specified tolerance to the project. A default output file name for the corresponding simplified polyline file is generated which is editable if desired. The tolerance value is also editable. - button can be used to remove any file(s) from the simplification routine by selecting the file(s) from the left bar of the spread sheet. x button clears everything from the dialog setting it afresh. = button is provided for simplicity in editing the threshold value for a bunch of flies at a time. After adding the polyline files module is ready to execute using Run button. The text browser provides information regarding any error or processing. After the operation is complete for all the files it is required to Close the dialog to processed to next step.