Description
Great Smoky Mountains National Park Travel Time: This reference is for 3 travel time model rasters, with time from Park Headquarters, Twin Creeks Science Center, and Oconaluftee Visitor Center modeled separately.
These rasters are Travel Time Cost Surface Models (TTCSM) created by NPS I&M staff, and models estimated travel time from starting locations to any point wihtin GRSM. Each model is for a different starting location: Park Headquarters (HQ), Twin Creeks Science Center (TWCR), and Oconaluftee Visitor Center (OVC). The models are created using the NPS TTCSM toolbox in ArcGIS, and raster values are in minutes traveled (rounded down to nearest minute). The resolution is 10M. The following assumptions are made by the modeling tool:
1. Travel starts at the given starting point, and then follows roads, trails, and off trail travel to reach any point.
2. No travel can occur on terrain with a slope of over 40 degrees. Areas on slopes over 40 degrees, or which cannot be reached without traversing said slopes, will return a NoData Value.
3. Travel values time out at 640 minutes (10 Hours, 40 minutes). After this, a NoData value is given. Generally, this only occurs in areas of signfiicantly steep slopes and dense understory vegetation.
4. Travel speed on roads is set as the legal speed limit. This model does allow travel on Administrative Roads, at a speed of 10 MPH.
5. Travel speed on trail is a function of slope, and of a user-defined speed reduction. For this model, GRSM public trails have no travel reduction, and un-maintained trails have a 50% travel reduction.
6. Off-trail travel speed is a function of slope, and a user-defined reduction of speed due to land cover. For the purpose of this model, areas with HIGH level of understory veg and/or significant wind damage are reduced 90%. Those with a medium level of understory vegetation reduced 66%, and those with light-to-no understory vegetation are reduced 50%.
7. The model allows for boat travel across Fonana Lake at a speed of 15 MPH, and access to administrative roads across the lake. Park streams do not effect the model, except that several user-defined high volume streams are set to a 90% time reduction (this eliminates the model from following large streams, where topography is often flatter).
8. Maximum walking speed is 3 mph, which can only occur on flat ground with no travel speed reductions. The model assumes no fatigue. Speed is reduced as slope increases and as various ground conditions are encountered.
9. Travel through non-park property is generally not allowed (except in a few instances of right-of-ways). Travel on non-park roads is allowed though, where they are included in model.
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Tags
- ttcsm
- grsm
- cost-surface
- great-smoky-mountains-national-park
- travel-time