################################################################################
### Importing GPS-traces from CSV-files
################################################################################
### Description:
### - This script imports GPS-traces from CSV-files.
###
### Preconditions:
### - existing database
###
### Postconditions:
###
### Authors:
### - Prof. Dr. Ralf Hartmut Güting, rhg@fernuni-hagen.de
### - Thomas Uchdorf, thomas.uchdorf(at)fernuni-hagen.de
################################################################################

open database dortmundC;

# load raw data

delete Trk101215;

let KDRSchema =
   [const rel(tuple([
      Latitude: real, 
      Longitude: real, 
      UTC: string, 
      Altitude: int,
      Distance: real,
      Speed: int,
      Date: string,
      Name: string,
      Sat: int
   ])) 
   value ()];

let Trk101215 =
   KDRSchema
   csvimport['/Users/fernuni-student/secondo-data/gps-traces/Trk101215Modified.csv',
   7,
   "#",
   ","]
   consume;

#2.95 secs
#Result size 74346



# create Trip and Altitude for each day

let Onehour =
   [const duration value (0 3600000)];

delete DayTrips;

let DayTrips =
   Trk101215 feed 
   extend[
     I: str2instant(.Date + "-" + .UTC) + onehour, 
     P: makepoint(.Longitude, .Latitude),
     Alt: int2real(.Altitude) ] 
   sortby[Date asc, I asc]
   groupby[Date
   ; DayTrip: group feed approximate[I, P, [const duration value (0 300000)]],
     DayAlt: group feed approximate[I, Alt, [const duration value (0 300000)]] ]
   consume;

#3.79 secs
#result size 134


# compute trajectories

query DayTrips feed
   extend[Traj: trajectory(.DayTrip)]
   consume;


# alternative representation: split by trips

let Trips =
   DayTrips feed 
   projectextendstream[Date; 
      Trip: .DayTrip sim_trips[ [const duration value (0 300000)]] ]
   extend[Traj: trajectory(.Trip)]
   consume;

#3.71 secs
#result size 398