Sorry, let me explain: I had to "project" the points to the line because we can't expect the point we want to check will be exactly in the line we are checking.
BR, Jonathan 2013/1/7 Jonathan Kraemer <jonathankrae...@gmail.com> > Hey guys, > > The problem of just checking the distance from the point to the route is > that it will give a false positive in cases the point is actually after the > end of the route or before the beginning, for instance. > > What I did there is actually pure math. > > See: the route is actually a bunch of lines. Using math you can get the > equation of a line and using math functions, get the distance from a point > to a line, plus check if the projection of a point lies inside the limits > of the line. The tricky part is that in order to do all this calcs, we need > the start/end point of the route lines and the points positions as a > cartesian system, instead of latitude, longitude angles, X and Y dimensions > in meters. That's not a problem actually, with a good enough approximation, > we can convert lat,lon angles to X,Y distances. The result is not perfectly > accurate, but it's proven that it is enough, I did not see cases of false > positives in my app yet. > > Knowing that, here is more or less how I solved this: > > First of all, I am using the version 3 of the Google Maps API. > > So first step I make a look through all the points at the array > overview_path that the directions API returns. So I make this loop from > position 0 to "length-1" because overview_path contains points and I want > to read always the current point AND the next one, so I have a line. > > But before calculating any information, I convert the coordinates to > meters. > > With that in hands, I get the line equation, which is pure math. And again > using math, calculate the distance from each point to the line and also > project the point to the line and check if it is inside the limits (the > initial and final points I am considering). > > Now that I know if the point is in the limits and the distance from the > point to the line, I can check if it is close enough that I can consider > that point "in" the route. > > I am not sure if it is understandable for you guys, let me know and I will > try to make it simpler, I can share the code with you guys or I can create > a "service" so you can just load in your apps and use it, what do you think? > > BR, > Jonathan > > > > > > > > > > > 2013/1/4 Carlos Montelongo <monte...@gmail.com> > >> Hi Jonathan. >> If you can, please share with us your app. >> >> Thanks in advance. >> Carlos Montelongo >> >> >> 2013/1/4, winster <wtj...@gmail.com>: >> > Hi Jonathan, >> > >> > Good work! I've given my vote. >> > >> > You may have come across a scenario what I am searching for. I have a >> list >> > of points on map. I need to check which of these points lie on a route. >> > >> > >> > >> > >> > On Sun, Dec 30, 2012 at 8:54 PM, Jonathan Kraemer >> > <jonathankrae...@gmail.com >> >> wrote: >> > >> >> Hey Winster, >> >> >> >> I developed something that might help, please got o my app, which is >> >> participating on Google Places API Developers Challenge: >> >> http://enchentes.org , move the slider on the top right corner to 12m, >> >> for instance (doing that, the app will show flood spots on that level >> for >> >> a >> >> specific city) and get some directions by right clicking on the map > >> Get >> >> Directions From/To Here. You will see that routes that pass through the >> >> flood spots become red. >> >> >> >> If you like it, please vote for my app on the challenge: >> >> https://developers.google.com/places/challenge/gallery >> >> >> >> I can share with you guys how I did that if you think it solves the >> >> issue. >> >> >> >> BR, >> >> Jonathan >> >> >> >> Em segunda-feira, 12 de novembro de 2012 03h19min53s UTC-2, winster >> jose >> >> escreveu: >> >> >> >>> Hi Gautam, >> >>> >> >>> Can you please share your findings? I have a similar requirement. I >> have >> >>> a group of points (LAT/LON). When user selects a route (it can be any >> >>> route), I need to show the points from my group if they lie in the >> >>> requested route. Also how can we do it with a better performance? I >> >>> think, >> >>> once the user searches for a route, find the max and min LAT/LON, and >> >>> get >> >>> the points from my group. But still how to find out whether a point >> lies >> >>> in >> >>> route? >> >>> >> >>> Thanks >> >>> Winster >> >>> >> >>> On Tuesday, 29 November 2011 02:12:56 UTC+5:30, Gautam Thakur wrote: >> >>>> >> >>>> Thanks It worked. I also did the same after trying other things. got >> >>>> the route and all the coordinates of polyline. then just used the >> >>>> distance between two points function to get the minimal with a >> >>>> threshold set. >> >>>> >> >>>> On Nov 28, 1:13 pm, yip cto <cto...@googlemail.com> wrote: >> >>>> > On 27 Nov., 23:22, Gautam Thakur <gautam.c...@gmail.com> wrote: >> >>>> > >> >>>> > > Hi there, >> >>>> > >> >>>> > > I have a set of latitude and longitude and I want to know if >> >>>> > > between >> >>>> > > two end points, are there any of the other locationlie? Is it >> >>>> > > possible to perform this using some google maps api to check for >> >>>> > > location enroute ? >> >>>> > >> >>>> > You can use the directions service to generate arouteand then check >> >>>> > the returned polyline coordinates. May be this solves your problem. >> >>>> > No >> >>>> > garantuee :-) >> >>>> >> >>>> -- >> >> You received this message because you are subscribed to the Google >> Groups >> >> "Google Maps API V2" group. >> >> To view this discussion on the web visit >> >> https://groups.google.com/d/msg/google-maps-api/-/_e6w0YwXFKAJ. >> >> >> >> To post to this group, send email to google-maps-api@googlegroups.com. >> >> To unsubscribe from this group, send email to >> >> google-maps-api+unsubscr...@googlegroups.com. >> >> For more options, visit this group at >> >> http://groups.google.com/group/google-maps-api?hl=en. >> >> >> > >> > >> > >> > -- >> > Regards >> > Winster >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "Google Maps API V2" group. >> > To post to this group, send email to google-maps-api@googlegroups.com. >> > To unsubscribe from this group, send email to >> > google-maps-api+unsubscr...@googlegroups.com. >> > For more options, visit this group at >> > http://groups.google.com/group/google-maps-api?hl=en. >> > >> > >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google Maps API V2" group. >> To post to this group, send email to google-maps-api@googlegroups.com. >> To unsubscribe from this group, send email to >> google-maps-api+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/google-maps-api?hl=en. >> >> > > > -- > Jonathan Kraemer > -- Jonathan Kraemer -- You received this message because you are subscribed to the Google Groups "Google Maps API V2" group. 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