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Table 1 Step-wise approach for the spatial classification of GPS points

From: Using Global Positioning Systems (GPS) and temperature data to generate time-activity classifications for estimating personal exposure in air monitoring studies: an automated method

What temperature zone is used? Criteria for assigning points spatially compared to the base geospatial data (buildings, roads)? (in order) What activity classification is assigned?
None. This occurs before zones are considered (all points that fit the criteria are assigned) Points with speed from the GPS >5 km/hr and within 20 m of a road segment In Transit
Flat zone1 (temperature is relatively constant) Points with GPS speed < 5 km/hr and within 25 m of road segment In Transit
Points within 25 m of subjects’ home Home
Points within 5 m of subjects’ school School
Points within 15 m of any other building Indoors Other
Points remaining (unclassified) Outdoors
Transition zone (temperature is changing) Points with GPS speed < 5 km/hr and within 5 m of road segment In Transit
Points within 5 m of subjects’ home Home
Points within 5 m of subjects’ school School
Points within 2 m of any other building Indoors Other
Points remaining (unclassified) Outdoors
  1. 1Within flat zones, a spatial criterion was applied for all points in the zone, using only the location of the center (obtained using the “mean centers tool” in ArcGIS) point in the cluster.