display map on Pocket PC

[ephemera]

I have a city map file which is size of 1.7 M ...I wanna display the map on PocketPC whose main memory is 32M...i try to use memory-mapped file but it is slow to load the whole map.
who guy has a better method to handle this problem?
thx in advance!

[ephemera]

noone know about the problem?

[nelo]

Do you want to keep the map on the pocket pc permantly? Or do you just need to display it for a moment? Is the map supposed to be edited on the device? Where is the map coming from?

[gstercken]

It also depends on the format of the map - is it a bitmap, or vector graphics? In any case, you'll probably need to organize the map data as a database, so you'll be able to load individual tiles or detail levels as they are needed.

[ephemera]

Originally posted by gstercken
It also depends on the format of the map - is it a bitmap, or vector graphics? In any case, you'll probably need to organize the map data as a database, so you'll be able to load individual tiles or detail levels as they are needed.

Thx for your reply.
The map is vector graphics which include roads ,rivers,administration regions etc. The map is divided with longitude and latitude grids.The file of the map is organized by the different geographic data.The program loaded the memory-mapped file of the map file,but it is too slowly in pocket PC.Does the better mothed of loading the map file exit?
thx in advance

[ephemera]

Originally posted by nelo
Do you want to keep the map on the pocket pc permantly? Or do you just need to display it for a moment? Is the map supposed to be edited on the device? Where is the map coming from?

thx for your reply
The map is just for navigation so it is only used when required.The map is not used for edit. The map is not general format such as MapInfo or ArcoInfo format.It is defined individually.
Do you know better method than loaded map using memory-mapped file?
thanks in advance

[gstercken]

Originally posted by ephemera
Does the better mothed of loading the map file exit?

Well, as already said: Store your map data in a database, in a way that allows you to selectively load the required information, not the entire file. A good starting point for indexing the records would possibly be the long/lat grid.

[ephemera]

Originally posted by gstercken
Store your map data in a database, in a way that allows you to selectively load the required information, not the entire file. A good starting point for indexing the records would possibly be the long/lat grid.

Thank your reply
How would I organize the map file in a database?
which database would I choose?
I recently learned something about spatial index such as KD-Tree,R-Tree R+-Tree... Should I divide the entire map file according to the property of the geographic objects into different files?Should I organize the map files by using my own format?
database or map files organized by spatial index by my own format,which is better?

I consider two reasons resulting in loading map slowly.One reason is the way that the map is organized and another is the method that the map is loaded in the memory.

The method that I used memory-mapped file to loading the map files has most efficient performance,does it?
thank in advance