Label Routes based on GPS coordinates in R/MATLAB - matlab

Question

I have three fixed points say A, B and C and several routes to commute between them, they can be in any order. Trip starts and ends at A. Image of routes, fixed points and reference points.
I have 1000s of GPS files in which I need to label the routes that were taken. The GPS files record Latitude, Longitude (in degrees), speed, distance traveled each second and cumulative distance.
I think of the following algorithm: Identify a reference point on each route at a fixed distance (say d) from each of point A, B and C. Now scan the GPS file for the first occurrence of either of Point A, B or C. Since its a GPS measurement, there may not be an exact point corresponding to A, B or C. So, we can find the first occurrence of a point within say 0.1 mile of either A, B or C.
Now start calculating the cumulative from Point A as we move towards B or C. when cumulative distance reaches close to d (again it may not be exactly d), we record coordinates of that point and find the reference point which is closest to it. The closest reference point will give me the route. I need to assign this route from start point to the second occurrence of either of A, B or C. For example, after traveling ‘d’ miles from either of A, B or C, we find that coordinate is closest to Point 3 in the Figure, we say that the route is BA. If the closest point is 2, then route is AB.
Now we go to second occurrence of A, B or C and then find a point after distance d and find a closest reference point to that point. Assign routes and so on.
Please help me with the code. Either R or MATLAB.

Answer 1

So, I wrote a code with a lot of for loops. It works well for me, no errors. Takes about 9 seconds to process a single file of 15000 rows and identify all 8 routes I need. So far so good. Just looking to find a more optimized program or a faster program. I am a beginner at programming.
gpsdata <- read.csv(file = filename, header = TRUE)
####lat and long of route start/end points
# Route Start Point: Routes A and C on Cates Avenue
cateslat = 35.781999
cateslon = -78.668252
#Route Mid: Intersection of AC13, Morning Dove Road
morlat = 35.882035
morlon = -78.645653
#Route End: RTP
rtplat = 35.895431
rtplon = -78.868958
}
#REFERENCE POINTS FOR ROUTE IDENTIFICATION ON EACH ROUTE
{
routea_lat = 35.795400
routea_lon = -78.641243
routec_lat = 35.821031
routec_lon = -78.687069
route1_lat = 35.913527
route1_lon = -78.714348
route3_lat = 35.922331
route3_lon = -78.842865
}
##### ROUTE START POINT TOLERANCE in miles
route_tol = 0.02
##### Reference POINT TOLERANCE for Identifying Routes (in miles)
ref_tol = 0.5
##Calculation Starts Here
n = length(gpsdata$Timestamp) ##File length
#Find point q where we first reach starting route (within 0.01 miles)
for (i in 1:n){
if((distm(c(gpsdata$Longitude[i], gpsdata$Latitude[i]),c(cateslon,
cateslat),fun = distHaversine)*0.000621371)<route_tol){
q=i
break
}
else
{
q=1
}
}
### First Route: Either A-Out or C-Out
for (i in q:n){
if((distm(c(gpsdata$Longitude[i], gpsdata$Latitude[i]),c(morlon, morlat),fun
= distHaversine)*0.000621371)<route_tol){
r=i
break
}
else
{
r=1
}
}
gpsdata1=gpsdata[(q+1):r,]
for (i in 1:length(gpsdata1$Timestamp)){
if((distm(c(gpsdata1$Longitude[i], gpsdata1$Latitude[i]),c(routea_lon,
routea_lat),fun = distHaversine)*0.000621371)<ref_tol){
gpsdata1$Route='A-Out'
break
} else if((distm(c(gpsdata1$Longitude[i],
gpsdata1$Latitude[i]),c(routec_lon, routec_lat),fun =
distHaversine)*0.000621371)<ref_tol){
gpsdata1$Route='C-Out'
break
} else{
gpsdata1$Route='Error-Check Data'
}
}
#Second Route: possibilities- 1-Out, 3-Out, A-In, C-In
#From Here we can either go back to Cates Avenue or go to RTP
for (i in r:n){
if((distm(c(gpsdata$Longitude[i], gpsdata$Latitude[i]),c(rtplon, rtplat),fun
= distHaversine)*0.000621371<route_tol) || +
(distm(c(gpsdata$Longitude[i], gpsdata$Latitude[i]),c(cateslon,
cateslat),fun = distHaversine)*0.000621371<route_tol)){
s=i
break
}
else
{
s=1
}
}
gpsdata2=gpsdata[(r+1):s,]
for (i in 1:length(gpsdata2$Timestamp)){
if((distm(c(gpsdata2$Longitude[i], gpsdata2$Latitude[i]),c(route1_lon,
route1_lat),fun = distHaversine)*0.000621371)<ref_tol){
gpsdata2$Route='1-Out'
break
} else if((distm(c(gpsdata2$Longitude[i],
gpsdata2$Latitude[i]),c(route3_lon, route3_lat),fun =
distHaversine)*0.000621371)<ref_tol){
gpsdata2$Route='3-Out'
break
} else if((distm(c(gpsdata2$Longitude[i],
gpsdata2$Latitude[i]),c(routea_lon, routea_lat),fun =
distHaversine)*0.000621371)<ref_tol){
gpsdata2$Route='A-In'
break
} else if((distm(c(gpsdata2$Longitude[i],
gpsdata2$Latitude[i]),c(routec_lon, routec_lat),fun =
distHaversine)*0.000621371)<ref_tol){
gpsdata2$Route='C-In'
break
} else{
gpsdata2$Route='Error-Check Data'
}
}