When using a negative distance on a buffer it is possible that the buffer might collapse if the buffer is larger than the size of the feature. This effect may be desirable in some situations, but not others. Please consider adding a "minimum result size" parameter to the buffer function.
Consider the following for a buffer using the following inputs
Here is an example of how this could work assuming that the Buffer Size = "-20", and the new Minimum Result Width = "10"
|Original Feature Size||Result Size||Notes|
|100||60 (100-(20*2))||Standard Buffer. Note the size of 60 is obtained by a negative buffer on both sides|
|15||10||Normally this would result in an empty geometry, however since the the minimum result size is set the feature will not collapse.|
|5||5 or 10?||If a feature is smaller than the minimum result width then I do not know if we should force the shape to get larger, or leave the shape alone....|