Due to restrictions, I have an application that requires line features to be selected if they are within a user defined tolerance from a points data set. I can not currently use any third party API to perform so have written an efficient algorithm that completes this task effectively. The application will be used by people that may or may not have a sufficient grasp on spatial concepts such as the defined unit of measure for their data set, or parameters requiring 'acceptable' values in map units.
- The use of the Tolerance parameter and whether I should keep the tolerance in a commonly known unit such as Centimetres, Meters or Kilometres and perform the required calculations to massage the input into an appropriate value; or
- Assume the user knows the data, or has the ability to ascertain the data sets map units and enter an intelligent, useful parameter value.
What is the more accepted practice?
If Befuddlement 1 is the accepted practice or considered more user friendly, can you proved the some direction towards ascertaining the Datum and other relevant coordinate information to perform the required function.
If Befuddlement 2 is more generally accepted, then case solved. Though it does make the solution easier and more straight forward, I feel forcing the user to go through a discovery process may lessen the user experience of the software.
Any thoughts on the matter would be greatly appreciated.