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1 Natural Resource Program Center Kirk Sherrill - GIS Specialist Brent Frakes – Geographer Stephani Schupbach – GIS Specialist NRPC – I&M Division – GIS Program Fort Collins, CO George Wright Society Conference GIS Rapid Fire – March, 2011 TTCSM - SOP Travel Time Cost Surface Model (TTCSM) Inventory & Monitoring Division – GIS Program
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2 Natural Resource Program Center The TTCSM: Is a GIS Python Model which: - Calculates travel times from defined point(s) to other locations in an AOI -Dynamic: User and Park Specific -Uses readily available GIS Data Efficient Field Data Sampling Design and Planning Packaged as two python scripts Requiring only basic programming experience Moderate GIS experience Inventory & Monitoring Division – GIS Program
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3 Natural Resource Program Center Inventory & Monitoring Division TTCSM is a linear model which performs : –Cost Surface –Speed Surface –Travel Cost Surface –Travel Time Modeling TTCSM - Schematic Inventory & Monitoring Division – GIS Program
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4 Natural Resource Program Center Inventory & Monitoring Division Cost Surface -Represents the amount of travel speed resistance per cell -Generated in a simple overlay manner -Key Steps: -Determine desired input layers and order -Assign Percent of Maximum Travel Speed (PMTS) values for each data layer Inventory & Monitoring Division – GIS Program
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5 Natural Resource Program Center Inventory & Monitoring Division Speed Surface -Defines the travel speed (seconds/per meter) per cell -Function: -Road Network Speed -Trail Speed -Hillslope Speed -Trail and Hillslope Speed are defined using Slope values and Toblers (1993) equation: T obler, W. 1993. Three presentations on geographical analysis and modeling. Technical report. 93-1, National center for geographic information and Analysis, University of California, Santa Barbara. Inventory & Monitoring Division – GIS Program
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6 Natural Resource Program Center Travel Cost Surface -Final Travel Speed at which movement in a cell occurs. Travel Cost Surface (miles/hour) for ROMO Inventory & Monitoring Division – GIS Program
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7 Natural Resource Program Center Final Step: Travel Time Modeling 1. Traditional Cost Distance Modeling ArcGIS Cost Distance Function Isotropic Model (treats all directions as equal) Travel times for a TTCSM which used Cost Distance Modeling Inventory & Monitoring Division – GIS Program
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8 Natural Resource Program Center Directionality Matters (Anisotropic) – incorporate the influence of Slope More Realistic User Specific Travel Times (Upslope and Downslope) 9 Predefined Path Distance Scenarios Travel Speed by Slope for five different flat surface walking speeds when using path distance modeling with a linear Path Distance Scenario. Inventory & Monitoring Division – GIS Program 2. Path Distance Modeling - ArcGIS Path Distance Function
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9 Natural Resource Program Center Travel Time Modeling Output: - Travel Time Grid(s): Hours, Minutes, or Seconds Least Cost Paths One Way or Round Trip Least Cost Paths Travel time least cost paths using an inverse linear path distance travel time model Inventory & Monitoring Division – GIS Program
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10 Natural Resource Program Center TTCSM Summary -Dynamic in nature to accommodate user Specific Travel Time Modeling Needs -Outputs Travel Time Grids and Travel Time Least Cost Paths -Runs in the Python Scripting Language on a computer with ArcGIS 9.3 -Working on Arc10 functionality – ESRI Problem between versions! Scripts and SOP are Downloadable at: http://nrinfo.nps.gov/http://nrinfo.nps.gov/ - Search for TTCSM Inventory & Monitoring Division – GIS Program
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11 Natural Resource Program Center Thanks & Questions? Inventory & Monitoring Division – GIS Program
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