How to cache Google map fragments for offline use?

Question

Just as Nokia OVI cards can be used offline, there must also be some way to cache Google maps. Any clues?

Answer 1

Unfortunately, I found this link, which apparently indicates that we cannot cache them locally, so this question is a moot point.

http://support.google.com/enterprise/doc/gme/terms/maps_purchase_agreement.html

4.4 Cache Limitations. The Client cannot pre-retrieve, retrieve, cache , index or store any Content or part of the Services , except that the Client can store limited amounts of Content solely to increase the customer’s sales performance due to network delays and only if the Client does this temporarily, reliably and in such a way that (a) does not allow the use of Content outside the Services; (b) is only session (after closing the browser, any additional storage is prohibited); (c) does not manipulate or aggregate any Content or part of the Services; (d) does not prevent Google from accurately tracking page views; and (e) does not alter or correct attribution in any way.

Therefore, we are unable to legally use Google graphics fragments offline.

Answer 2

If you try to cache tiles served by Google, this may be a violation of the Google Terms of Service (if, under certain circumstances, if you bought your corporate Google Maps API). This is why gmapcatcher crossed out their list. See http://code.google.com/p/gmapcatcher/issues/detail?id=210 .

In the gmapcatcher URL above, you will also find a shell script that can load fragments (or, according to the author).

There are other projects that are trying to make Google Maps available offline:

http://code.google.com/p/ogmaps/

http://code.google.com/p/gmapoffline/

Finally, if Google Earth can meet your needs, you can use this. Standalone use of Google Earth requires a Google Earth Enterprise license under http://www.google.com/permissions/geoguidelines.html .

Please note that the previous page also says: "You cannot clear or otherwise export Content from Google Maps or Earth or save it for offline use." Therefore, if you try to cache tiles, it will almost certainly be considered (in any case, Google) a violation of the Terms of Service.

Answer 3

update:

I found Google Maps terms of use:

Section 10.5

No caching or storage. You will not pre-select, cache, index or store any content that will be used outside the Service, except that you can store a limited amount of Content solely for the purpose of improving the performance of the implementation of the API Maps due to network latency (and not to prevent accurate tracking by Google use), and only if such storage: is temporary (and in no case more than 30 calendar days); safe Does not manipulate or aggregate any part of the Content or Services; and does not change the attribution in any way.

This means that we can cache for a limited time.

Answer 4

Http://www.google.com/earth/media/licensing.html has a Mobile section that contains:

As in our online terms, if you use our APIs or your own version of Google Maps for mobile devices (for example, on a phone with an Android phone or iPhone), special permissions are not required, but you should always keep your Google name visible. Offline caching of our content is never allowed.

Answer 5

You want to use the spatial index. This reduces 2d complexity to 1d complexity and is used in many mapping applications. You can download my php class hilbert curve at phpclasses.org. Much simpler is the z-curve. Translate the x and y coordinate into binary, and then combine both values. The upper bound is the most significant bits. Then use the boxes to structure the folders on the disk, for example: 1/2/3 // 4 - the path to the fragments of the first level.

Answer 6

You can use Open Street Map: you will find dozens of different layers and types of maps, and it is absolutely free. You can download all the necessary map fragments. And, of course, since anyone can improve a map, it displays more information than Google maps. If you need help, you can ask a community that is also very active.

Answer 7

On Android platforms, Oruxmaps ( http://www.oruxmaps.com ) does a great job caching all WMS sources. It is available in the game store. I use it daily in remote areas without any connection, it works like a charm.