Table 1 McGrail and Humphrey’s rules to define the variable application of distance-decay to service catchments (Step 1)
Rule | Explanation | Outcome |
|---|---|---|
1. Population within 10 minutes of the service | Initial (local neighbourhood) catchment without distance decay | No decay |
2. Population linked to their nearest 25 services | Services likely to provide access to populations (beyond 10 minutes) that have few alternative options | No decay |
3. Population <5000 and < 0.5 population of the Service town | Services in larger towns likely to provide access to significantly smaller nearby populations, but not vice-versa | No decay |
4. All other scenarios | Services less likely to provide access to populations as distance increases. | Decay |