INeighbourhood Opeator to identify  Blackspot of accident

Discussion created by manojsinghrana on Jun 20, 2012
Hi All,

I am working on a transportation application.I have batch process written in VB to find Blackspots(areas where concentration of accidents is more).

Function used : IneighbourhoodOperator.FocalStatics
Input of environment variables : 1) Feature class containing selected accidents
                                            2)Grid height(300),width(300),cell size(60)

Output : Raster dataset which is converted into feature class and then polygons are drawn on features based on some criteria. 

Issue : Input1:I filtered accidents in accident feature class based on two expressways A and B.
          Input2:I filtered accidents based on expressway A alone.

When I compare location of polygons on expressway A in both these cases it is not the same.The polygons have shifted a little bit due to which number of accidents covered in polygon have changed.

I am suspecting this has something to do with width,height and cell size used in Focal analysis.

Questions:1.Whether it is appropriate to use Neighbourhood analysis to do such type of analysis.
              2.What is the appropriate value of width,height and cell size should be used.

Any help is Appreciated.Thanks.