Mapping India – Mobile, GPS and more
I have been using Google maps on my E61. It works great, both with and without GPS (using Cell-id). However, there`s one missing feature – offline usage, and I especially miss it when there is no connectivity (GPRS is way slow and highly unreliable here). I tried Nokia maps but not as detailed as Google maps.
I recently came across MGMaps and instantly fall in love with it. It’s an awesome application which support maps from multiple sources like Google (not officially), Yahoo, Yahoo-India, MSN, OpenStreet maps etc. The best thing about MGMaps is ability to use offline maps. It can even show you a real-time compass with speed etc. Try it out if you haven’t. If you like to know more, here is a fantastic blog post. You can find some information about offline fetching here and here.
For N800, I use Maemo Mapper. It works great and much better that Nokia’s default map application.
I use both E61 and N800 in coupled with Holux GPSSlim 240. It is a very small GPS (claimed to be smallest GPS so far) based on SiRF III low power chipset. It can track upto 20 satellite channels. It is really quick in acquiring lock in open space. There is a minor sensitivity issue in-house due to its tiny patch antenna but works great outside. Once it acquires lock, I can even put it in my pocket.
By default, the only way to connect GPSSlim 240 unit to your laptop is using Bluetooth. To connect using USB, a special cable is required (needs to be purchased separately). However, you can make this cable really quick from other mobile cables like DCU-11 which has USB to serial converter (3.3v) such as Prolific PLC-2303. Simply, replace mobile-end connector with a mini USB type-B connector. It only took me 15 minutes to convert a DCU-11 clone cable to the one which can work with GPSSlim 240. Here are the steps:
- Open the connector and carefully note down the TXD (to PC) and GND cables. In case of DCU-11 (DCU-11 link), those are the cables which connects to pin 5 (TXD) and pin 10 (DGND). This website is handy to find pinout of mobile connector.
- Desolder connector.
- Solder TXD cable to pin 3 and DGND cable to pin 4 of mini USB connector.
- Optionally, solder RXD cable to pin 2 of mini USB connector for sending commands to GPS (Hot-start, cold-start, warm-start, factory reset)
- Optionally, solder VCC cable for charging.
That’s all, your special USB cable is ready to be used with GPSSlim 240. To test your cable, connect it with your laptop, start serial console (minicom or HyperTerminal) and turn GPS ON. GPS will start emitting the NMEA sentences which you can see on serial console. Connect it with Google Earth and start exploring!!!
Real-time tracking with Google earth
Google earth free version does not support GPS and requires $20 per year Plus subscription to use GPS. Even after subscription, GPS support is limited and only supports Garmin and Magellan devices.
However, Google kept the API to control Google earth open and there are couples of free and donation-ware apps which uses this API to interface Google earth with GPS. These apps read position from the GPS and uses API to control Google earth. I just wonder, since Google kept the API open, why can’t it include GPS support in free version too. Anyway, here are two recommended apps to use GPS with free version of Google earth:
Do comment if you know better options. Enjoy exploring!!!