Thanks William, yes it's true, this feature by google is really useful. But I know that those downloads can get quite big and I think the cost of that data may deter users in countries like Tanzania. I need to confirm the approximate cost though.
Abzier On Thursday, December 5, 2019 at 5:14:29 PM UTC, William Denniss wrote: > > On the topic of Plus Codes and offline navigation, you can actually do > this pretty well in Google Maps too - at least where the download feature > <https://support.google.com/maps/answer/6291838?co=GENIE.Platform%3DAndroid&hl=en> > > is available. > > On a recent trip, I downloaded the area where was travelling to my device > while on Wifi at home using that feature of Google Maps. Then on the road, > I could punch in a plus code to bring up the pin, then use driving > navigation directions to get there - all without any internet connection. > > William > > On Thu, Dec 5, 2019 at 4:28 AM Andreas B <and...@bocops.de <javascript:>> > wrote: > >> Hi Abizer, >> >> yes, something like that should be possible. One great feature of plus >> codes is that nearby codes mostly have the same prefix. This means that, if >> the user wants to navigate to some location that is new to them, it would >> be easy to look up all codes already stored on the user's device that start >> with the same, say, eight characters. This would allow you to help your >> users find their destination by a statement like *"Thomas's home is near >> Tees Pizza"* (assuming that the user already navigated to the Pizza >> place before). >> >> If there's no known place near the destination itself, something similar >> could be attempted for nearby tiles (eight characters adjacent to the >> destination), tiles along the direct route to the destination, or if all >> else fails for the whole rectangular area that has start and destination in >> opposite corners. In that case, a navigation statement could be something >> along the lines of *"You want to go to Thomas's home. Looks like Tees >> Pizza is about half way between your current location and that place."* >> >> The above seems to be realistic for users that use the app a lot in the >> same place (for example their home town), if you cache a good number of >> previously used locations. It is less realistic to do for the whole country >> in advance. >> >> I did a quick back-of-the-envelope calculation to estimate what we're >> talking about. With an area of ~950,000km², I would except there to be on >> the order of 35,000 six-digit prefixes in use across Tanzania - but each >> "tile" that could be addressed by a six-digit prefix has a size of >> approximately 30km². I think it would be possible to find a "best city >> name" for that number of tiles, for example by outsourcing that task to >> your users - but that would mostly help with cross-country navigation and >> postal services, but not really be useful for a step-by-step navigation >> within one city. This data (35,000 x some bytes for a city name) would >> probably fit on most user's devices, though, so it could be great to have >> for offline functionality. >> >> Going from six- to eight-digit prefixes means a factor of 400, so roughly >> 14M entries - which is likely too massive to either store or build in the >> first place. >> >> On Wednesday, December 4, 2019 at 5:54:48 PM UTC+1, Abizer Jafferjee >> wrote: >>> >>> Hi Andreas, >>> >>> Thanks for the quick response. This is a really good idea. Currently, my >>> focus was just on getting users used to the idea of using a plus code as an >>> alternative to an address. But I didn't think enough about how helpful the >>> plus code would be in navigation because I thought you'd still need to be >>> online to make use of plus codes to get directions. >>> >>> I wonder if it would be possible to build even more detailed offline >>> text navigation through the geo tiling idea. E.g if someone wants >>> directions from current location to point B and the app has stored plus >>> codes of some points in between e.g. road intersections, then we could >>> string together a complete route by calculating the distance between >>> closest plus codes at each point of the route. >>> >>> While the urban areas within countries like Tanzania have good data >>> connectivity yet still expensive, the rural areas sometimes don't have any >>> connectivity at all so a completely offline routing system would be really >>> useful for organizations working within these areas. >>> >>> On Tuesday, December 3, 2019 at 9:49:19 AM UTC, Andreas B wrote: >>>> >>>> If you are including the OLC library in your project directly, you will >>>> be able to calculate a plus code from the user's device location, and also >>>> translate any plus code back into latitude/longitude coordinates. All on >>>> device, without any need for connectivity: >>>> https://github.com/google/open-location-code/tree/master/java >>>> >>>> Calculating the distance could then be performed on the lat/lng >>>> coordinates using something like the Haversine formula ( >>>> https://en.wikipedia.org/wiki/Haversine_formula) - or, alternatively, >>>> following something like this wrapper class I created a while ago if very >>>> rough approximations are good enough for an offline, step-by-step >>>> navigation: >>>> https://github.com/bocops/open-geotiling/blob/master/java/org/bocops/opengeotiling/OpenGeoTile.java >>>> >>>> In any case, displaying the current and destination plus codes while >>>> the user approaches might help them find the exact location more easily. >>>> >>>> On Tuesday, December 3, 2019 at 6:20:27 AM UTC+1, Abizer Jafferjee >>>> wrote: >>>>> >>>>> Actually, connectivity is a big issue because mobile data is still >>>>> relatively expensive in Tanzania. >>>>> >>>>> Currently the QR code has a deep-link back to the digital address >>>>> within the app. >>>>> >>>>> One option I thought of was to create a USSD application which can be >>>>> triggered from the app and would retrieve text directions to the location. >>>>> >>>>> I like your idea about giving some helpful information. How would I >>>>> calculate the distance between two plus codes? And how would I know the >>>>> plus code of the location the user is standing at? >>>>> >>>>> Thanks Andres >>>>> >>>>> On Monday, December 2, 2019 at 3:52:54 PM UTC-5, Andreas B wrote: >>>>>> >>>>>> That makes sense, thanks for the explanation. I agree with the >>>>>> conclusion that plus codes aren't that useful in any scenario where both >>>>>> users are online, and can just access a database with all the necessary >>>>>> information. I wonder if it would make sense for your app to use plus >>>>>> codes >>>>>> as a fallback for scenarios where one or both users sharing an address >>>>>> are >>>>>> currently *not *online? >>>>>> >>>>>> For example, I assume the QR codes displayed by your app contain an >>>>>> ID value referencing the address data. If the QR code *also* >>>>>> contained a plus code directly, that could be used to at least display >>>>>> *something* even if the user is not currently online. >>>>>> >>>>>> Would a statement like "1.5km to the north-west - more information if >>>>>> you're back online" be useful, or is connectivity not an issue that >>>>>> needs >>>>>> to be solved in your app's case? >>>>>> >>>>> -- >> Public site: http://www.openlocationcode.com/ >> Github project: https://github.com/google/open-location-code >> Demo site: http://plus.codes/ >> --- >> You received this message because you are subscribed to the Google Groups >> "Plus Codes Community Forum" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to open-location-code+unsubscr...@googlegroups.com <javascript:>. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/open-location-code/ceb0aa3b-b712-4180-b021-ea0b1c1ec6e3%40googlegroups.com >> >> <https://groups.google.com/d/msgid/open-location-code/ceb0aa3b-b712-4180-b021-ea0b1c1ec6e3%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- Public site: http://www.openlocationcode.com/ Github project: https://github.com/google/open-location-code Demo site: http://plus.codes/ --- You received this message because you are subscribed to the Google Groups "Plus Codes Community Forum" group. 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