Location Features

We incorporate all features in RAPIDS-Location, which includes location variance, location entropy, travel distance, etc.

In addition, we also added more features (duration of staying) for specific points of interest, including places for living, study, exercise, and relaxation. The following tables list out specific features.

Feature Name	Unit	Description
`hometime`	minutes	Time at home. Time spent at home in minutes. Home is the most visited significant location between 8 pm and 8 am, including any pauses within a 200-meter radius.
`disttravelled`	meters	Total distance traveled over a day (flights).
`rog`	meters	The Radius of Gyration (rog) is a measure in meters of the area covered by a person over a day. A centroid is calculated for all the places (pauses) visited during a day, and a weighted distance between all the places and that centroid is computed. The weights are proportional to the time spent in each place.
`maxdiam`	meters	The maximum diameter is the largest distance between any two pauses.
`maxhomedist`	meters	The maximum distance from home in meters.
`siglocsvisited`	locations	The number of significant locations visited during the day. Significant locations are computed using k-means clustering over pauses found in the whole monitoring period. The number of clusters is found iterating k from 1 to 200 stopping until the centroids of two significant locations are within 400 meters of one another.
`avgflightlen`	meters	Mean length of all flights.
`stdflightlen`	meters	Standard deviation of the length of all flights.
`avgflightdur`	seconds	Mean duration of all flights.
`stdflightdur`	seconds	The standard deviation of the duration of all flights.
`probpause`	-	The fraction of a day spent in a pause (as opposed to a flight).
`siglocentropy`	nats	Shannon’s entropy measurement is based on the proportion of time spent at each significant location visited during a day.
`circdnrtn`	-	A continuous metric quantifying a person’s circadian routine that can take any value between 0 and 1, where 0 represents a daily routine completely different from any other sensed days and 1 a routine the same as every other sensed day.
`wkenddayrtn`	-	Same as circdnrtn but computed separately for weekends and weekdays.
`locationvariance`	meters2	The sum of the variances of the latitude and longitude columns.
`loglocationvariance`	-	Log of the sum of the variances of the latitude and longitude columns.
`totaldistance`	meters	Total distance traveled in a time segment using the haversine formula.
`avgspeed`	km/hr	Average speed in a time segment considering only the instances labeled as Moving. This feature is 0 when the participant is stationary during a time segment.
`varspeed`	km/hr	Speed variance in a time segment considering only the instances labeled as Moving. This feature is 0 when the participant is stationary during a time segment.
`numberofsignificantplaces`	places	Number of significant locations visited. It is calculated using the DBSCAN/OPTICS clustering algorithm which takes in EPS and MIN_SAMPLES as parameters to identify clusters. Each cluster is a significant place.
`numberlocationtransitions`	transitions	Number of movements between any two clusters in a time segment.
`radiusgyration`	meters	Quantifies the area covered by a participant.
`timeattop1location`	minutes	Time spent at the most significant location.
`timeattop2location`	minutes	Time spent at the 2nd most significant location.
`timeattop3location`	minutes	Time spent at the 3rd most significant location.
`movingtostaticratio`	-	Ratio between stationary time and total location sensed time. A lat/long coordinate pair is labeled as stationary if its speed (distance/time) to the next coordinate pair is less than 1km/hr. A higher value represents a more stationary routine.
`outlierstimepercent`	-	Ratio between the time spent in non-significant clusters divided by the time spent in all clusters (stationary time. Only stationary samples are clustered). A higher value represents more time spent in non-significant clusters.
`maxlengthstayatclusters`	minutes	Maximum time spent in a cluster (significant location).
`minlengthstayatclusters`	minutes	Minimum time spent in a cluster (significant location).
`avglengthstayatclusters`	minutes	Average time spent in a cluster (significant location).
`stdlengthstayatclusters`	minutes	Standard deviation of time spent in a cluster (significant location).
`locationentropy`	nats	Shannon Entropy computed over the row count of each cluster (significant location), it is higher the more rows belong to a cluster (i.e., the more time a participant spent at a significant location).
`normalizedlocationentropy`	nats	Shannon Entropy computed over the row count of each cluster (significant location) divided by the number of clusters; it is higher the more rows belong to a cluster (i.e., the more time a participant spent at a significant location).
`timeathome`	minutes	Time spent at home.
`timeat[PLACE]`	minutes	Time spent at `[PLACE]`, which can be living, exercise, study, greens.