OpenStreetMap is a great ecosystem - I'm a long term contributor.
Some pointers:
- CoMaps is a fork of Organic Maps, which forked long time ago from Maps.me
- OsmAnd is similar. It has more features but is slower and clunkier
- If you see errors/missing stuff on OpenStreetMap, fix them. You need a free account for this. There are various tools to help out, such as the editor on Osm.org. Beginner-friendly editors are https://MapComplete.org (which has thematic maps; disclaimer: I'm the main dev) and https://streetcomplete.app
jech
> It has more features but is slower and clunkier
Just to clarify: OsmAnd has more features, CoMaps and Organic Maps are much faster.
(Aside: I'm using CoMaps myself. The main missing features are tracking (I use OpenTracks for that) and public transportation (I use a website for that). End of aside.)
flexagoon
OsmAnd is not that much slower nowadays since they added the new OpenGL renderer. It is, however, less convenient and pretty. I think OsmAnd really shines for things like hiking, whereas for regular urban navigation CoMaps works just as well.
hv42
Exactly my experience as well. OSMAnd is a lot better for hiking as it has 3d views, hiking routes, topo maps and better routing in general. Comaps is great for city navigation or casual usage
shiandow
I also really like the star chart they added recently. Seems like a minor thing but it's just really handy to have it available for the few occasions you need it.
coldpie
I gave CoMaps a shot this morning, but it doesn't support public transit in my city (Minneapolis/Saint Paul area) which is an instant deal killer. Bummer.
olyjohn
Wait, I just used the tracking the other day and generated a GPX from it. It also drew me an elevation map and gave me some other info about the trip. Is there some other tracking that it can't do?
jech
I stand corrected, CoMaps can do tracking. It was introduced in Organic Maps a couple of years ago, but I was already using OpenTracks, so I never switched away from it.
ihatehn
CoMaps lets you record a route, though it's somewhat limited
flaburgan
There is tracking in Comaps, what do you miss from it?
atkirtland
What website do you use for public transportation?
lucgommans
I was recently recommended https://api.transitous.org (it's a webapp despite the domain). It can do things like "someone can pick me up on the far side and I don't mind walking 30 minutes at the start at 6 km/h, what's the optimal route to take?"
Revolutionary! Finally I don't have to look on a map to find all stations in walking/cycling/driving distance and then route to/from every possible combination of start and end station manually to see what busses and trains run there. And repeat the process with each schedule change in each involved country. Every other transport app that I know of will try to keep you within a few hundred metres of a bus stop or train station at all times and say "there exists no route" before telling you to cycle 10 minutes or from which station you have the shortest remaining distance by taxi or whatever
schubidubiduba
There is actually work being done to integrate exactly this API into Comaps! Although it will certainly take some more time, especially until these more niche routing features are available
jraph
KDE Itinerary, a mobile and desktop application, is becoming better and better for this. It's based on MOTIS / Transitous.
I just discovered cartes.app can do this too!
jech
I've found that websites specific to a single European country or, in the case of France, to a single city are the ones that work best.
yread
rome2rio.com works reasonably well to at least get an idea where to look up the exact prices and timetables
chantepierre
Hey, a simple question : I would like to contribute not features nor POIs but actual paths. In my region the maps lack a lot of forest paths, and others that are on the map are long gone due to nature closing them. Something like the strava heatmap is a lot more accurate because hikers and trail runners make the actual paths appear. I often use https://onthegomap.com (which uses OSM) to plan routes and find that the hiking paths do not match reality. What is a straightforward way for me to contribute ? I have GPX traces of all those not-on-maps well-trodden paths if that helps.
emj
There is an upload GPX track function on the website. You then draw your paths with the online editor, above those tracks. Edit: you do this because GPS is not clean enough and you need to choose which paths connects where.
You will often forget the details if your GPX are old. E.g. was it really possible to use a bicycle on that path, did those two actually connect or was it me running 150m through the Forrest as a short cut.
So it takes work to get right.
chantepierre
Thanks, that was so simple ! Just contributed my first missing path.
On mobile, Vespucci is the full-featured OSM editor that lets you edit whatever you want. On desktop, JOSM is the main one, though it takes a bit of figuring out.
leokennis
Unfortunately (but logically I think) the OSM-ecosystem is very Android leaning - so missing out on a large % of street walking smartphone wielding would-be mappers.
Also, to get "basic non-tech regular people" involved in improving the maps, it's too complicated (i.e. even the simplest street or sidewalk has a lot of tags with arcane names, which need to be set to exact values according to very deeply buried and confusing documentation).
For street level small maintenance level enhancements, I would envision (and need) an app that would consist of:
- See the point/lines/area that make up the map at the place where I stand
- Add a new point/line/area or drag existing ones to change their shape
- Answer some simple questions about what you added or edited (i.e. for an area: "is this grass?" or "is this parking space?", for a line "is this paved?" or "can a car drive here?")
- Optionally, either directly publish the changes or add them to some review queue where an expert can asynchronously review and catch the most basic mistakes or abuse
Although I do need to say that despite this app not existing, OSM is often the most detailed and up to date map in my area. I think it heavily depends on if your neighborhood has an OSM enthusiast or not.
matkoniecz
StreetComplete is preparing release for Apple devices
GoMap!! also exists for Apple devices
cicko
Please no! I like the fact that the maps are created by people who actually know something about the topic.
maelito
Note that there are lots of OSM editors, but sadly not a single one as simple as Google Maps for end-users.
I'm working on cartes.app, we've designed a very simple opening hours editor, but we're missing lots of other edition features.
We should also mention Everydoor or of course osm.org, the main one.
In the end, you can modify way more things yourself on OSM than Google Maps, but through a complexe ecosystem that you have to understand first, and most are missing place reviews and simple image uploading.
Both cartes.app and mapcomplete enable these, through two different databases. Mapcomplete enable Mangrove reviews and Panoramax image uploads.
Cartes enables ATProto place reviews, with pictures, and soon Panoramax upload too.
zikduruqe
You can also do it directly from CoMaps if you have an OSM account.
amatecha
Yeah! CoMaps was actually what I used for my very first contribution to OSM! Nice lil gateway to an awesome ecosystem. Mega kudos to the CoMaps devs for doing such a great job with it.
I will try out CoMaps. Tried OsmAnd and it takes forever to get gps position on my iphone.
nickspacek
I used this for my family's recent trip in Lisbon and Prague. It worked great! The OSM data was reasonably up-to-date for all of our destinations; I don't remember encountering bad information, even though I often double-checked with other mapping providers (which aren't immune to issues with out-of-date information).
One awesome feature was being able to find "drinking water" while we were walking around. I did come across a tap that was shut off/unavailable, but only once. Again, this is more of an OSM data thing than CoMaps, but I generally found the app pleasant to use.
There sometimes feels like there is something slightly off with the "Route To/From" UX that I can't put my finger on, but no complaints.
Contortion
The problem I have most of all with the routing is that it seems to default to my location as either the From or To value (whichever is the one I haven't selected). Once that's been chosen it's not immediately clear how to change it, all you can do is view the route. That's a fine solution when you're immediately looking to go somewhere, but it's not great when you're trying to plot a route between two places in advance.
I've been using CoMaps for a few months and only just discovered that if you choose another location on the map once you've got an initial route and select Route To/From, it then updates the current routing.
lucgommans
> The problem I have most of all with the routing is that it seems to default to my location as either the From or To value (whichever is the one I haven't selected). Once that's been chosen it's not immediately clear how to change it
Yeah this is an oft-asked question at least for OsmAnd, but I was recently corrected on this myself: so long as you don't press 'start' on the route, you can always change the from position freely and it won't flip back to your current location. You can close the navigation window (back button, swipe it away, or tap on the map) to get the map view back in full-screen for further browsing and selecting another point that you want as departure point, waypoint, or (subsequent) destination. Rinse and repeat until you have the route figured out with all the waypoints :)
I use this a lot for planning mapping routes. Another protip is to go into the waypoints view and on the top right you can do traveling salesman sorting to get the shortest way that visits all waypoints
CoMaps/OrganicMaps I don't know; I'm one of those who grew up with OsmAnd and got used to having all those features
ihatehn
We're working on the routing UI! It's a common hangup.
goobatrooba
Best ist you can directly report the broken tap from the app. So the dates will be fixed.
matkoniecz
Even better is to edit directly at osm.org.
Reporting from within CoMaps generates note that will sometimes wait years for verification.
bluebarbet
A potted history of mobile OSM-based mapping.
First there was Osmand. AKA OSMAnd or officially OsmAnd.
It was was powerful but complicated. Normies had never heard of it and preferred Maps.me, a user-friendly alternative with an opaque business model. Then something at Maps.me turned sour and the more privacy-minded normies turned to Organic Maps. Then something at Organic Maps turned sour and some of them moved to CoMaps.
During all this time (literally 15 years), Osmand improved steadily and became more powerful than ever. Even the UX got (a bit) better. It is by far the best mapping app, either FOSS or commercial. And yet somehow it continues to languish in relative obscurity.
ihatehn
We tell our users that OsmAnd is great if you want a mapping swiss army knife in your pocket: it does a little bit of everything, for power users. It has plugins and customizability.
CoMaps' mission is to be an accessible usable privacy-first FOSS map app for the entire world (average people) and so we always have our eye on the typical expected user experience and what obstacles remain between them and uninstalling those non-FOSS privacy-invading apps, but we're not going down the rabbit hole of adding all sorts of niche powerful features: OsmAnd already does that very well, and the world doesn't need two OsmAnds.
gedankenstuecke
100% agree - I think even some of the CoMaps contributors use OsmAnd for the rare specialist use cases. I know I do: CoMaps is my main map app that I use basically every day and works perfectly for all of my common/normal use cases. but once in a while I have a map/nav need beyond that and then OsmAnd's customizability is great!
Vinnl
To illustrate this, look at OsmAnd's most recent blog post [1]. They've recently been looking at adding pretty extensive Astronomy features. Before that, they added a lot of nautical tooling [2]. This is all very cool if you use that, but if you don't, the laundry list of such features make it harder to find the features you do use.
I used OsmAnd for a long time, and it's a great app that I learned how to use well. And while I do miss some features (most notably the Wikivoyage integration for offline travel guides), ultimately the simplicity of CoMaps makes it much more pleasant to use for the thing I mostly use it for: getting around cities.
Even if it adds some complication I really enjoy just having both features available when I need to. But then I'm a sucker for gadgets.
In a way both provide answers to the question, what is that light?
Performance is the main reason to prefer CoMaps but they've gotten a lot better at it (and inevitably you have to sacrifice some speed for customisability)
bluebarbet
Indeed. I have a theory that software complexity tends to bring with it a subjective perception of slowness that might not show up if measured empirically. At one point Osmand certainly had an issue rendering lots of POIs, but it was addressed and these days the app feels (to me) acceptably quick.
cicko
OsmAnd's search feature always sucked whereas CoMaps' is just beautiful. I wish it was simpler to share a location between the two, once I find it.
andrewshadura
Please please, fix the long-standing bug: make it possible to use the navigation in "north is always up" mode.
schubidubiduba
That has been possible for a long time, by pressing the location button to toggle it. And recently some more edge cases regarding this were fixed.
pcthrowaway
I haven't tried using osmand much yet, but one concerning thing is the info I encountered that long (as in, cross-country) trips could take minutes (or hours?) to provide a route for. I haven't actually tested it yet, but it definitely gave me pause
bluebarbet
That warning was unjustified. In my experience it's never more than a few tens of seconds, and usually much quicker.
artyomsv
It is real but not so dramatic as you heard. Offline routing must walk the graph across many downloaded regions, so time grows fast with distance. Trip inside one country is usually seconds, whole continent can be minutes. Standard trick is to put two or three intermediate points on the route. Then engine solves several short problems instead of one huge one, and answer comes almost immediately. Also OsmAnd can use online routing when you have signal, offline engine is fallback. So the bad case happens only when you plan very long route and have no connection at same time, which is not typical situation.
cicko
World also doesn't need two copies of maps. Please fix.
nkjvhb
OsmAnd is a great powerusers app. I use it daily.
However, I would not recommend OsmAnd to a normie. My family members, especially the older ones, all use CoMaps because it is much more friendly to them.
c0nsumer
100% this. I use OsmAnd very very frequently (it displays on my dash via Android Auto whenever I drive), but try and do something like load a GPX and show the line in a given color... Or add a pin at a specific point... It's not straightforward at all.
Powerful, but very not straightforward.
NoboruWataya
I use this regularly when I go on long walks out of the city (including the couple of times I've done stretches of the Camino de Santiago). The offline map support and being able to load and display GPX tracks are really helpful there. Not only because you can sometimes find yourself with spotty reception in remote areas, but also because if you are out all day and your phone battery is not the best, you can just stick on airplane mode which massively saves on battery.
CoMaps also makes it quite easy to edit information about businesses etc, so if you spot something that isn't right you can correct it right there.
Also, for long walks/hikes, OSM is excellent. Most people tend think think of OSM as "Google Maps but worse" but IMO it is clearly superior for this use case (at least, for reasonably popular routes). It will display a lot of paths that Google Maps won't and also has far more granular detail, so you can use it to find nearby water fountains, picnic benches, even bins and so on.
matkoniecz
> OSM as "Google Maps but worse" but IMO it is clearly superior for this use case (at least, for reasonably popular routes).
for less popular areas it may be worse, but Google Maps often will be degraded even more
I have yet to find case where for hiking/cycling Google was better (I am kind of cheating as I edit on OpenStreetMap and fix problems if found)
prmoustache
I've been visiting some parts that are new to me on a rental car and my partner used Google maps with android auto to set the routes. In a week gmaps tried to send me twice against traffic into one-way streets and once in one that didn't even exist
r0xsh
Funny to see this app pop up on Hacker News.
I recently started tinkering with CoMaps to make it more useful for bikepacking, since I do quite a bit of it. I don’t plan to turn this fork into a product, it’s mostly something I’m building for my own needs ; but I figured it might be interesting to share:
As a fellow keen bikepacker (about six months a year), I prefer OSMAnd. More features relevant to our community, and you can install Brouter as a routing engine.
dollop3041
The surface feature is really a great add-on that is missing from the original app for bikepacking. Thank you for sharing this.
zikduruqe
Even neater, I use CoMaps on my linux laptop, with a USB GPS receiver.
It beats using IP based Geocoding.
lucgommans
Another alternative to geoIP could be WiFi-based location detection (comparing which WiFis are near you to a database). https://beacondb.net aims to replace Mozilla's shut-down location services, with public data releases once a proper anonymisation scheme has been figured out to avoid another Mozilla event. Google and Apple apparently also have usable back-ends: afaik it's not documented or meant for public use so ymmv, but the reverse engineered API is apparently super stable and not requiring any auth.
In case you have a second device where you'd like location, or ever don't have the USB GNSS receiver on you or something :)
zikduruqe
Yep. When I was screwing around getting geoclue to play around with NMEA sentences, I ran across beacondb. I might replace geoclue's back end with it next time I feel like messing around.
rambambram
I'm a little confused. You mean for getting your own location, I guess?
zikduruqe
Yes. Default location on your linux computer will use geoclue2, which will give you a location based on your IP address. My location is about 30 miles away since my IP is associated with Google Fiber.
Using a cheap USB GPS receiver you can get to meters level resolution, could use it mobile as a navigation device, and NTP timing too if you want.
rambambram
Thanks, I get it now. I was thinking you used it for geolocating webvisitors or something, already wondered how you'd do that with your own GPS receiver.
maelito
Note that the OpenStreetMap international conference is taking place this weekend in Paris.
This is nice to see. I've been a long-time contributor to OpenStreetMap and a long-time user of applications in the ecosystem. I recently tried the CoMaps fork of Organic Maps and was surprised by a few quality of life improvements. For example, the one named in the article about being able to receive periodic map updates outside of the monthly application update cycle. Another subtle example is the color scheme in CoMaps being slightly more pleasant.
mixmastamyk
Recently noticed it is on flatpak as well, so can use from my tablet.
dariosalvi78
it's a great app, I use it whenever I have bad Internet coverage or when I want to use open street map, for example when hiking. It's really a competitor of commercial apps.
nkjvhb
CoMaps is the best. They recently integrated Panoramax into CoMaps, which gives street view in many locations.
schubidubiduba
Pretty sure the stretview part is still WIP
_joel
I was the sysadmin for the original version of https://sahanafoundation.org/eden/ over a decade and a half ago (!), this would have been amazing as a component. Not sure how well my HTC desire or whatever was current would run it though.
BlackRabbit1
I love it for hiking, walking in cities and driving a bicycle.
thoughtpeddler
I had a student in my class propose an "AI for emergency response" that leveraged local models. Not a far stretch from what we see here with CoMaps, plus a small Gemma or similar low-parameter model running on-device to help with anything required at the 'last-mile' (beyond just mapping/navigation) during an earthquake, fire, flood, etc.
after about 6 years of using OSMAnd, i’m pivoting to CoMaps for a hike through switzerland that i’m leaving for tonight. i don’t actually need all of the features of OSMAnd and just downloading maps costs a subscription now. id pay outright for it but i just can’t justify a subscription for how infrequently i use it
gentile
You can download Osmand~ from F-droid which doesn't limit downloads. Or you could even download the map from another provider like bbbike or geofabrik, use osmandmapcreator (needs java) to convert the pbf to obf and then import it into the phone.
andrewshadura
Come on, OsmAnd's subscriptions are super cheap for the value you're getting.
swasheck
maybe. i use it every other year though and otherwise simply don’t. i never said that it wasn’t super cheap, i just said it wasn’t cost-effective for my usage profile.
constantlm
maps.me was my goto for years, but that has since devolved into a mess with ads and upselling. I recently discovered CoMaps, and it is excellent for my needs.
akeck
Pocket Earth Pro also provides off-line OSM maps. That's what I use. I'll check out CoMaps as well.
seemaze
as an alternative, I’ve used the Guru Maps (formerly Gaia) offline downloadable vector maps for years with great success.
Everybody here compares CoMaps with OsmAnd, but for me most interesting part of article is different. Their bottleneck was not rendering or routing, it was that every map update needed new app release, so it had to pass through app store review. They decoupled this, processing went from 10 days to about 3, now fresh data weekly for whole planet, and around 35 hours when emergency is declared.
Very unglamorous engineering, and it is what actually made buildings traced in Tasking Manager reach people standing in the rubble.
Also worth to say: you can help with this part from home. During activation the tracing is done from satellite imagery, local knowledge is not required.
indianwashlets
KotMapps, the let-me-konstantly-fiddle-with-our-UI, by Kotstantin from a past bin.
Some pointers:
- CoMaps is a fork of Organic Maps, which forked long time ago from Maps.me - OsmAnd is similar. It has more features but is slower and clunkier - If you see errors/missing stuff on OpenStreetMap, fix them. You need a free account for this. There are various tools to help out, such as the editor on Osm.org. Beginner-friendly editors are https://MapComplete.org (which has thematic maps; disclaimer: I'm the main dev) and https://streetcomplete.app
Just to clarify: OsmAnd has more features, CoMaps and Organic Maps are much faster.
(Aside: I'm using CoMaps myself. The main missing features are tracking (I use OpenTracks for that) and public transportation (I use a website for that). End of aside.)
Revolutionary! Finally I don't have to look on a map to find all stations in walking/cycling/driving distance and then route to/from every possible combination of start and end station manually to see what busses and trains run there. And repeat the process with each schedule change in each involved country. Every other transport app that I know of will try to keep you within a few hundred metres of a bus stop or train station at all times and say "there exists no route" before telling you to cycle 10 minutes or from which station you have the shortest remaining distance by taxi or whatever
I just discovered cartes.app can do this too!
You will often forget the details if your GPX are old. E.g. was it really possible to use a bicycle on that path, did those two actually connect or was it me running 150m through the Forrest as a short cut.
So it takes work to get right.
Also, to get "basic non-tech regular people" involved in improving the maps, it's too complicated (i.e. even the simplest street or sidewalk has a lot of tags with arcane names, which need to be set to exact values according to very deeply buried and confusing documentation).
For street level small maintenance level enhancements, I would envision (and need) an app that would consist of:
- See the point/lines/area that make up the map at the place where I stand
- Add a new point/line/area or drag existing ones to change their shape
- Answer some simple questions about what you added or edited (i.e. for an area: "is this grass?" or "is this parking space?", for a line "is this paved?" or "can a car drive here?")
- Optionally, either directly publish the changes or add them to some review queue where an expert can asynchronously review and catch the most basic mistakes or abuse
Although I do need to say that despite this app not existing, OSM is often the most detailed and up to date map in my area. I think it heavily depends on if your neighborhood has an OSM enthusiast or not.
GoMap!! also exists for Apple devices
I'm working on cartes.app, we've designed a very simple opening hours editor, but we're missing lots of other edition features.
We should also mention Everydoor or of course osm.org, the main one.
In the end, you can modify way more things yourself on OSM than Google Maps, but through a complexe ecosystem that you have to understand first, and most are missing place reviews and simple image uploading.
Both cartes.app and mapcomplete enable these, through two different databases. Mapcomplete enable Mangrove reviews and Panoramax image uploads.
Cartes enables ATProto place reviews, with pictures, and soon Panoramax upload too.
One awesome feature was being able to find "drinking water" while we were walking around. I did come across a tap that was shut off/unavailable, but only once. Again, this is more of an OSM data thing than CoMaps, but I generally found the app pleasant to use.
There sometimes feels like there is something slightly off with the "Route To/From" UX that I can't put my finger on, but no complaints.
I've been using CoMaps for a few months and only just discovered that if you choose another location on the map once you've got an initial route and select Route To/From, it then updates the current routing.
Yeah this is an oft-asked question at least for OsmAnd, but I was recently corrected on this myself: so long as you don't press 'start' on the route, you can always change the from position freely and it won't flip back to your current location. You can close the navigation window (back button, swipe it away, or tap on the map) to get the map view back in full-screen for further browsing and selecting another point that you want as departure point, waypoint, or (subsequent) destination. Rinse and repeat until you have the route figured out with all the waypoints :)
I use this a lot for planning mapping routes. Another protip is to go into the waypoints view and on the top right you can do traveling salesman sorting to get the shortest way that visits all waypoints
CoMaps/OrganicMaps I don't know; I'm one of those who grew up with OsmAnd and got used to having all those features
Reporting from within CoMaps generates note that will sometimes wait years for verification.
First there was Osmand. AKA OSMAnd or officially OsmAnd.
It was was powerful but complicated. Normies had never heard of it and preferred Maps.me, a user-friendly alternative with an opaque business model. Then something at Maps.me turned sour and the more privacy-minded normies turned to Organic Maps. Then something at Organic Maps turned sour and some of them moved to CoMaps.
During all this time (literally 15 years), Osmand improved steadily and became more powerful than ever. Even the UX got (a bit) better. It is by far the best mapping app, either FOSS or commercial. And yet somehow it continues to languish in relative obscurity.
CoMaps' mission is to be an accessible usable privacy-first FOSS map app for the entire world (average people) and so we always have our eye on the typical expected user experience and what obstacles remain between them and uninstalling those non-FOSS privacy-invading apps, but we're not going down the rabbit hole of adding all sorts of niche powerful features: OsmAnd already does that very well, and the world doesn't need two OsmAnds.
I used OsmAnd for a long time, and it's a great app that I learned how to use well. And while I do miss some features (most notably the Wikivoyage integration for offline travel guides), ultimately the simplicity of CoMaps makes it much more pleasant to use for the thing I mostly use it for: getting around cities.
[1] https://osmand.net/blog/eclipse-explorer/
[2] https://osmand.net/blog/nautical-maps
In a way both provide answers to the question, what is that light?
Performance is the main reason to prefer CoMaps but they've gotten a lot better at it (and inevitably you have to sacrifice some speed for customisability)
However, I would not recommend OsmAnd to a normie. My family members, especially the older ones, all use CoMaps because it is much more friendly to them.
Powerful, but very not straightforward.
CoMaps also makes it quite easy to edit information about businesses etc, so if you spot something that isn't right you can correct it right there.
Also, for long walks/hikes, OSM is excellent. Most people tend think think of OSM as "Google Maps but worse" but IMO it is clearly superior for this use case (at least, for reasonably popular routes). It will display a lot of paths that Google Maps won't and also has far more granular detail, so you can use it to find nearby water fountains, picnic benches, even bins and so on.
for less popular areas it may be worse, but Google Maps often will be degraded even more
I have yet to find case where for hiking/cycling Google was better (I am kind of cheating as I edit on OpenStreetMap and fix problems if found)
I recently started tinkering with CoMaps to make it more useful for bikepacking, since I do quite a bit of it. I don’t plan to turn this fork into a product, it’s mostly something I’m building for my own needs ; but I figured it might be interesting to share:
https://github.com/r0xsh/CoBike
It beats using IP based Geocoding.
In case you have a second device where you'd like location, or ever don't have the USB GNSS receiver on you or something :)
https://github.com/deepin-community/geoclue-2.0/blob/master/...
Using a cheap USB GPS receiver you can get to meters level resolution, could use it mobile as a navigation device, and NTP timing too if you want.
Most of the project cited here will be presented.
https://2026.stateofthemap.org/
https://gurumaps.app/
Very unglamorous engineering, and it is what actually made buildings traced in Tasking Manager reach people standing in the rubble.
Also worth to say: you can help with this part from home. During activation the tracing is done from satellite imagery, local knowledge is not required.