iPhone and NOAA BSB, USGS DRG and custom maps

Published on Sep 04, 2008

iPhone supports displaying of Google Maps tiles very well by standard Maps.app application. A man can zoom and look around just by finger gestures.

Behind the user interface the Maps.app is loading tiles from Google server and storing them in to SQLite cache file. Some people proved that you can prepare your own SQLite cache with custom maps and let it use by Maps.app on iPhone.

Then you have a map of your choice and this map is even available off-line, so your iPhone don’t need to use internet connection to get the tiles as they are stored in the disk of the phone already.

Such approach was documented for Google Sky tiles for example: http://www.dailyack.com/2007_12_01_archive.html

Nowadays there is even a GUI application for iPhone allowing you to switch prepared maps: http://code.google.com/p/iphoneofflinemap/

Unfortunatelly the maps are usually prepared in advance on a computer from half legal map sources by software like Global Map Download Tool.

But I don’t see a problem to prepare tiles from legally owned maps like NOAA BSB navy charts or USGS DRG topo maps.

Jerry Morrison from Google Inc. in his presentation “Scaling Google Maps from the Big Screen Down to Mobile Phones” mentioned that iPhone uses tiles with size 64x64px, MapTiler should be able to generate such tiles quite well.

I was thinking maybe somebody can push my MapTiler application to generates tiles directly into the SQLite cache database for simple upload into iPhone. Anybody interested?

P.S. There is now way how to design a 100% web-based map application with iPhone Web Touch API.

Petr Pridal

CEO, Software architect
Published on Sep 04, 2008