Individual crash pin-maps

The new version of Map Magic, included with this upgrade can now produce pin maps with dots that represent each individual crash. These dots are properly located with regard to distance and direction from the intersection, and "stick" to the road they occurred on. (even if the road curves) Map Magic creates a theme of these dots and has a three step process that:

1.	Creates a theme from an Intersection Magic accident list. The dots are placed at the intersections nearest to the crash without regard to distance and direction from the intersection.

2.	Moves the crashes based on their distance and direction from intersection fields. There may still be crashes "piled on top of each other" if they occurred at the same spot.

3.	Offsets the overlapped crashes on a 45 angle so that each crash dot is visible. Once this step is complete, the theme may be modified to show various attributes in different colors or sizes. The theme is valid ArcView theme and all data is still available about each crash dot.

The steps to perform this Magic are:

1.	Make sure the Map Magic link is working properly by using the High Accident Location List dialog to geocode and display a theme showing all the locations that have crashes you want to display. Details for this are available in the Map Magic help file.

2.	Create a diagram or dataset in Intersection Magic. (File / New diagram) The diagram may be in summary or schematic view mode.

3.	Select Reports / Listings / All accidents as if to create a report listing these accidents.

Select New RPT to create a new report format, or Edit RPT to modify an existing format. Using the RPT format editor, add the newly available field called XYCoord to the list of fields. Be sure to uncheck the "lookup" option for this field. Also be sure that the distance field is selected for the list, and the dir_from_int field is selected for output. Select ok to save the format. Remember this report file, as you can use it again and avoid this step of the process next time.

5.	Check the box "delimit data with" for commas. This will produce an ascii text file suitable for import into any database program, including ArcView / Map Magic.

Select ok to produce the report. The resulting report is a comma-delimited data file containing each of the crashes in the diagram. Since this diagram may be "all data" or a corridor, or a "combined diagrams" data set, the crashes may be one or more locations. Save this file, remembering where you placed it and what it is called.

7.	Launch ArcView. There is a new shortcut on the Intersection Magic "window / GIS" menu for doing this, or you can start it in the normal manner from the start menu. Once in ArcView, open the view containing your map.

Click on the "locate individual crashes" button.

to raise the "offset point theme" dialog box. Enter the name of the data file that you just created in Intersection Magic and check the "step 1" box. Click on the "GO" button. The list of points will be created as a theme. At this time, notice if what you see is just two dots on the screen. If this occurs, then you had some locations in your diagram that had not been geocoded yet. One of those dots contains all the non-geocoded points. (all located at 0,0 on the map). Go back and re-geocode any of these points and start again if necessary.

Next, uncheck step 1, and check step 2. Again, select "GO". This process can take a while, it is a good idea to test it with a small data set first. Once this process is complete, your theme will contain points re-located for correct placement. At this point your data is correctly located, although difficult to see if many crashes happened at the same locations.

10.	The last step is to uncheck step 2 and check step 3, select "GO". Now any crashes that were overlapped will now be "stacked" on an angle.