11 Replies Latest reply on Mar 5, 2016 11:05 AM by BeatriceBeaubien

    Get Current Location

    regex

      Hi Everyone,

       

      After reviewing the Location function, I was attempting to use it to find the CURRENT location of an iPhone user with FileMaker Go.  However, it works great if I provide an Address, or a Longitude and Latitude, but how do you get the current long and lat of the user.  I want to compare an address with the current location, but for some reason it appears that it does not work.  Any thoughts on how to do this? 

        • 1. Re: Get Current Location
          lapcom

          Hi!

          Have you tried this?:

           

          Location

           

          Regards

          • 2. Re: Get Current Location
            regex

            Doesn't actually get current location without adding a location

            • 3. Re: Get Current Location
              lapcom

              It works. Did you allow Filemaker to access your iPhone Location?

              • 4. Re: Get Current Location
                jbante

                This blog post talks about how to get the location (coordinates, not address) of an iOS device.

                 

                This blog post talks about how to get coordinates from an address, so that the location of the iOS device and the address can be compared, such as to determine if a device is close enough to an address.

                 

                This blog post talks about how to figure the distance between two locations, such as between an address and a device.

                • 5. Re: Get Current Location
                  regex

                  I have tried location.  However, it appears to always comeback with a slightly different latitude and longitude.  As an example, if I use Google and get a 34.755410 Lat and a Long at -82.2655558 is might be slightly different using location which might give 34.755210 and long at -822655358.

                   

                  Is there a way to get an allowable range with FM?  I have 100 Meters, but does that mean the value will not change if in 100Meters, or could it vary even within 100Meters?

                  • 6. Re: Get Current Location
                    jbante

                    Geolocation has to allow for a margin of error due to several factors beyond our control. It's just a fact of life, even for Google. You can set an iPhone on a tripod and have it get location fixes over and over again from the exact same spot, and the coordinates you get will be a little different from moment to moment. This is normal. The first parameter to the Location and LocationValues functions is the desired accuracy radius, in meters. You can ask for a particular accuracy, but that doesn't guarantee that you'll get it. You can also ask for a larger radius (worse accuracy), and you may get a location fix faster and using less energy than you might with a smaller radius.

                     

                    This blog post analyzed the results from FileMaker Go's location functions to interpret exactly what "accuracy" means here. (It's a few years old, so some things may have changed since then.) For dedicated GPS devices for hiking or surveying, "accuracy" has one of a couple very precise mathematical meanings. The apps using the iOS location frameworks (such as FileMaker Go), "accuracy" is not well defined. If the reported accuracy is 100 meters, this does not mean you'll always get the same coordinates if you walk up to 100 meters away and get a second location fix, and this does not mean you'll always get coordinates within 100 meters if you get a second location fix from the same spot. If the accuracy radius you get for one fix is smaller than for another, the coordinates with the smaller radius are probably closer to the true coordinates; but there isn't necessarily a consistent logic to how much closer or how often.

                    • 7. Re: Get Current Location
                      beverly

                      Doesn't it rely on triangulation with cell towers and wifi in the area? I can guarantee that my "geo location" changes quite frequently with no other factors (not moving even an inch). Google maps can't find my street, but my wifi picks up closer on Apple Maps.

                       

                      beverly

                      • 8. Re: Get Current Location
                        DavidJondreau

                        A couple years ago, I was in a car on an iPad that had no cellular ability. I was not connected to a wifi hotspot. Yet Maps still gave me an accurate location! The iPad saw the Wifi networks available and could calculate its location just based on that. That really hit home to me.

                        • 9. Re: Get Current Location
                          jbante

                          It depends on what radios are available in the device. iOS will use whatever is available; Wi-Fi lookup on Wi-Fi-only devices, cellular triangulation and GPS on devices with cellular radios. (Cellular and GPS radios are a package deal on iOS devices, for some reason.) GPS has the greatest potential accuracy, but cellular and WiFi location are a reasonable complement for GPSs weaknesses.

                           

                          Technically, determining location based on Wi-Fi and cellular stations in the area isn't "triangulation." A device can't use the signal strength of a station to judge how far away it is (or its relative distance compared to other base stations) because there are plenty of things other than distance that affect signal strength. If my phone detects a cellular station, it knows that it's somewhere in the receiving area of that station, and that's about it. It's less triangulation, and more like a Venn diagram.

                          • 10. Re: Get Current Location
                            fitch

                            Interesting podcast episode of Reply All related to phone location:

                            https://gimletmedia.com/episode/53-in-the-desert/

                             

                            or read the story:

                            http://fusion.net/story/214995/find-my-phone-apps-lead-to-wrong-home/

                            • 11. Re: Get Current Location
                              BeatriceBeaubien

                              Thanks for the link to the update on this story, Tom.

                               

                               

                              Beatrice

                               

                              On Mar 4, 2016, at 19:18, Tom Fitch <noreply@filemaker.com> wrote

                               

                              /snip

                              or read the story:

                               

                              http://fusion.net/story/214995/find-my-phone-apps-lead-to-wrong-home/