To find Location name using lat/long coordinates without internet.

Can I get the location name using lat/long coordinates without the internet? ?? I am now involved in a project called kids tracker in which I should be able to track exact location name.
I am using atmega8 microcontroller along with GPS and GSM modules in which I am able to get coordinates.
Please help me how to get Name of the location using coordinates .
Thanks in advance

Dear picachu sir,
Please tell me the name of that project


Thanks in advance.

Could this be similar to pet locating devices? There are various types. There is the device which detects direction of a radio transmitter on a collar.

There is a service which tracks a pet collar. The method might be triangulation, or by cell tower, or by gps. They charge a fee.

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Can I get the location name using lat/long coordinates without the internet?

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For this you'll need an enormous database, similar to the gps device that says 'turn right at the next street' while you're driving.

You'll probably require coordinates as precise as one second. However your database may not list anything at pinpoint locations. Therefore you'll need to put some thought into how to search your database, in terms of town, street, building. Perhaps even altitude.

Dear bradtheread sir,
Can I get entire database of India map in a text file or any other format???
I will then store it in a SD card and reas it through microcontroller and can send that location name through GSM unit.

Punith R Puni said:

Dear bradtheread sir,
Can I get entire database of India map in a text file or any other format???
I will then store it in a SD card and reas it through microcontroller and can send that location name through GSM unit.

Click to expand...

If anyone has made such a database, I expect they charge money for it. If you're lucky there is a database for your locale, available through the municipal map-making department.

Consider the size of database your SD card can store.
One degree of latitude is 70 miles.
One minute is 1.17 mile.
One second is 100 feet.

Instead of a text database, could it be more practical to have a map on your SD card, labelled with latitude and longitude?

Why not send lat and long thru GSM and do the lookup on the other end of the link? The device on the other end of the link might be a smartphone or something rather less resource constrained then the tracking transmitter (And it might have internet access, in which case leaveraging google earth becomes possible).

GIS databases are almost never flat text, some sort of space partitioning tree structure is just far more useful.

Regards, Dan.

Dear bradtheread,
How can I read if I store entire map in my SD card. What is the format of it.
How can I read it from a microcontroller.

Please help me out.
Thanks in advance.

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Dear bradtheread,
How can I read if I store entire map in my SD card. What is the format of it.
How can I read it from a microcontroller.

Please help me out.
Thanks in advance.

You design a suitable data structure and (probably) use a PC to convert the map data to whatever structure you have decided to use, then store on the SD card.

I would suggest using a simple FAT file system on the card as that makes access from a PC really easy, and FAT file system implementations for small micros are commonplace, but the details of how best to do the GIS data is down to you.

A 2D BSP or Quadtree structure might be appropriate?

I still think that doing the map thing at the client rather then the tracking transmitter makes better sense however.

Regards, Dan.

Dear Dan Mills Sir,
I somehow got the entire india database in a text file which shows latitude longitude and location name of every possible location.
It has around 5lakh lines of data and its size is 27MB.
Can i be able to search for the location in this big file using microcontroller??
I am attaching the screenshot of the text file.
Please help.

Do you have a rapid memory search routine built in? If I had to write a routine, this is how I would do it. Suppose you have lat= 25.4567.

1) Search for a carriage return (ascii 13), or line feed (ascii 10). (Whichever is compatible with your format.)

2) Look at the next byte. Does it contain 2? If not then go to next line of data.
If so then look at the next byte. Does it contain 5? If not then go to next line of data.

3) If the bytes contain 25, then look at the entire number. Does it match latitude (within a margin of error)? If not then go to next line of data.

4) If so then look at the number for longitude. Does it match (within a margin of error)? If not then go to next line of data.
If so then print the entire line.

This is only a simple way. Some details can be added to make the search go faster.