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Why do maps apps have essentially no caching?
20 points by arcza 5 months ago | hide | past | favorite | 41 comments
I live in the UK. A very simple 2D vector costing a few bytes could show the UK as a right angled triangle at minimum zoom. But no, got no 4G? Sucks to be you. You just see a grid. Why is there zero caching of any sorts in Maps apps, which presumably consume millions of gigabytes of bandwidth every day in traffic, and countless amounts of energy polling the same imagery twice?

Apple Maps has high-level view capability, and also the option to download areas for offline viewing/directions. When you zoom out, it'll show you the borders of the offline-available area.

Obviously satellite imagery and traffic data doesn't work, but viewing the map, and getting directions within the offline-capable mode do work.

Furthermore, with data turned off, cities and highways for places outside nominated areas work too.

For example, I have no offline maps for anywhere in Europe, but I can see a map of UK to a scale where the little distance gauge shows 100km, and it shows cities (and highways between) such as London, Leeds, Sheffield, Liverpool, Guilford, Cardiff, etc.

Google maps has offline maps where you can pre-download a region

I use that all the time in areas with no cell service

Organic Maps is offline until it needs to download updated map information from Open Maps data.


Search just finds whatever matches sorted by distance so it may not fit one's needs.

Except when it decides to not work when you are on a trail 200 miles from the closest town lol. I hate Google.

I always take a few screenshots just in case

I downloaded the entire state of Rhode Island so I never really need to use data when traveling. It's fantastic.

Yeah but it’s Rhode Island so that’s like 6K

So does Apple Maps.

No search in Apple Maps when you're offline, so it's limited.

You definitely can search in offline mode.

No you can't. Put your iPhone in airplane mode and try.

I did just that before posting that comment, to confirm that it works as I understood it (ie searching for "restaurants" rather than just searching for a contact name which has an address).

In airplane mode the search prompt in maps even changes to "Search Offline Maps".

It's not possible to type into the search prompt of Apple Maps when in airplane mode.

It is possible, but it does depend on region though.

I can't search with an offline map in Thailand, but it works fine for an offline map in Australia: https://imgur.com/a/DA803mj

Mystery solved! Then we're both right.

A lot of the comments rightly point out that you can manually download offline maps.

But why don’t these apps automatically cache a map at some coarse resolution?

Google Maps automatically caches areas around your common saved locations (e.g. Home and Work). Outside that, what's the value? It's a bit niche to open your map for a cached rough outline of the planet.

I do wish the apps were a bit less stingy about letting you choose to fully offline large areas more easily though. The detailed road information is helpful when you don't have signal and if you travel for work it's often outside what a single box will capture. E.g. Google Maps lets you offline as much as you want (as far as I can practically tell) but you have to do it in many about-indiana-sized-rectangles instead of just saying "save these states" or being able to zoom out farther to a region directly.

Are you sure it doesn't? Google Maps on Android does, for me.

Zoom into some location you've never looked up before, in some country you haven't been to. Turn on airplane mode. You can pan around and the nearby areas will still be there. Zoom out, and previously cached tiles will still be available. Go to some other part of the world, and a coarse resolution version of their polygons should still be visible.

I think as of a few years ago, it also auto-caches tiles along a navigation route, but I can't find the announcement stating that anymore :(

I would think there are may reasons Google might do this; One may be if you have to download the data, they get to collect that data for use. Data for them is a commodity and being able to know who/when/where specific map data is being downloaded might be valuable. All hypothetical of course..

Apple Maps at least, seems to have coarse resolution without needing to actively browse the area first.

Apple Maps does this. I just confirmed it last week when I was international. I was honestly surprised at the detail in areas I had not marked for download.

What is the benefit of a map cached at a coarse resolution, though? does it let you navigate?

They do? Like there's Google Maps which has offline maps, you can select an area or multiple areas to download and keeps it up to date when you are connected to Wifi

Why is there absolutely nothing cached by default? How many times does the topology of the Atlantic Ocean change every day that an outline cannot even be shown? I get not caching high zoom levels, but there is literally zero optimisation here done.

If there's changes, you want the most up to date version. The vast majority of the map doesn't change in any given interval, but you don't know what areas did change, unless you want to send down a changelog stream.

That said, if you don't like what Google Maps does, there's lots of other choices. Here maps (from the Navteq/Nokia lineage) had pretty reasonable downloading options when I was using it on WP and is available on platforms that lived.

What is the utility of a map of all of Great Britain if you don’t also have the detailed data at a city and road level? It would be a lot of data if the apps were to try to cache it all the way down to the lowest zoom level. Should the apps always cache everything? If not what would be the cutoff? If you don’t have all the data, what benefit is the outline of the island?

Having a clear setting would be great. Casche for 1 day, 1 wee or 1 month? I would like to choose.

I think I would go for 1 month cache. Balance the possibility of change with the likelyhood of no change.

Have you tried Organic Maps?


Organic Maps has a low resolution world view, so it answers the question.

There was a feature for Google Maps, on Android; where you could tell it to download and keep a local copy of some small area so it could work without net.

As I recall it worked fairly poorly (still tried to load live urls) and wanted to re-download the cache once a day or more. It was not useful for the purpose.

I always took it to be "make as many people happy with the least effort," why continue to polish a product in ways like this that few will use or ever even notice is available?

Much better to spend effort inserting local businesses into peoples driving directions. They might've wanted to stop for coffee even if they told you a different destination.

I still use this feature all the time (we live in a rural area with many pockets of no reception). Yes, it will still try to fetch live data if you have a connection, but if you're out of LTE/5G range it won't. Or you can just turn on airplane mode and it'll always use the offline data.

In recent versions, it will also auto-cache tiles along the way if you navigate somewhere far away, even if you don't explicitly tell it to.

Both features have saved me from getting lost many times...

Offline maps? That still exists.

Yeah, those Maps ads... that's just going to be a feature technology historians will cringe over in 50 years

Both Google Maps and Apple Maps have support for offline maps. They both work very well.

I do not have an internet connection on my phone yet I am as dependent on navigation systems as anyone else!

might be off-topic but I'm interested in your internet-less phone situation. Is this your choice, i.e a dumb phone? Or perhaps connectivity is bad where you are?

I’ve got an iPhone. It’s for moral and epistemological reasons that I don’t want be reduced to a servomechanism of a global information system.

At least not 24/7. I’m happy to submit myself to silly nonsense for a paycheck, which is pretty close to the definition of having a job!

I’m also a songwriter and I need to be observing the real world and not the mediated representation. It’s my job to create the mediated representation! And with killer guitar solos!

Try this may give you much better control. https://organicmaps.app

No ads, no tracking, unbelievable. Just downloaded. Thanks

OsmAnd lets you download offline maps. Not sure atm if it can overlay realtime traffic data on top though.

I just enabled airplane mode, opened Google Maps and I can see everything in detail (no satellite imagery though) using Offline Maps.

You mean it should automatically cache everything you ever look up including satellite imagery?

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