Ultimately we employed PostGIS, which was more efficient and able to do the job. We began our experiment in QGIS and perfected the process, but ultimately failed because the software was not able to handle the large number of polygons: almost 2 million postal codes and over 60k grid cells. The process involved calculating the area of overlap and percentage of total overlap between each postal area and grid cell. Prevent measures not on route-This data validation option ensures that the input measure values for from measure and to measure values fall within the minimum and maximum range of measure values on the selected route.I was helping someone with a project this semester where we wanted to calculate overlap between two different polygon layers (postal code areas and grid cells) for over forty countries throughout the world.Merge coincident events-When all attribute values for a new event are exactly the same as an existing event, and if the new event is adjacent to or overlapping the existing event in terms of measure values, the new event is merged into the existing event and the measure range is expanded accordingly.Retire overlaps-The system will adjust the measure and start and end dates of existing events in such a way that the new event does not causeĪn overlap with respect to time and measure values.
Choose from the following data validation options to prevent erroneous input while characterizing a route with linear events:.Click the End Date drop-down arrow and choose the end date.Type the end date in the End Date text box.Choose the date that will define the end date of the events by doing one of the following:.The end date is optional, and if it is not provided, the event remains valid now and into the future. The start date defaults to today's date, but you can choose a different date using the date picker.
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