Version 3.0 of Bit Map requires users of previous versions to reinstall all of their maps.  This is a significant inconvenience for people with a large collection of installed maps, so some explanation is in order.  This page explains why this is necessary.

Bit Map's Goal

The original goal of Bit Map was for iPhone (and iPod Touch and iPad) users to be able to install any map image easily on their device, for a wide variety of common image file formats.  Bit Map has been remarkably successful in achieving this goal.  However, the simplicity of this concept, meant that a lot of complicated work had to be done by Bit Map to make it work.  The iPhone had to do a huge amount of image processing during the installation of each image in order to split it into many smaller images optimised for display, because the iPhone has limited amount of RAM and cannot manage very large images (and most map images are very large).

The Problems

This splitting and optimising of images takes a lot of time, a lot of battery power, and most significantly, a lot of RAM (memory) and for a significant number of users this RAM usage was more than the iOS would allow, so the operating system would kill Bit Map for using up too much memory (Bit Map disappears back to the home screen, like a crash).

With the advent of iOS 4 and applications left running in the background, there is even less RAM available to Bit Map to use for the process of splitting and optimising images, and this problem has become more critical for more users.

The Solution

In order resolve this problem, it has been decided that the image processing (splitting and optimising of images) should be done before the images are installed into Bit Map.  Ie, this processing should be done on the desktop or laptop computer.  In this way, the once-off hard CPU/RAM/Power intensive work of image processing need never be done on the iPhone itself, and installation of the files will be very quick.

For this solution to be palatable to users who enjoyed the simplicity of installing any old image file into Bit Map with older versions, it was decided that the desktop/laptop tool to do this job needs to meet the following criteria:

• output a single image file for each raw image file fed into it (and not a series of image tiles)
• run on both Mac OS X and Windows operating systems (and preferably others)
• free to download

The file format produced by this tool must meet the following criteria:

• individual portions of the image can be read from it without having to read the entire file into memory first
• bonus:  File format already in common use by users of digital mapping and navigation software.

A file format has been determined which meets all of these criteria, and work is under way to integrate this into Bit Map 3.0.

Advantages

In Bit Map 3.0, the new image file format will have the following advantages:

• Eliminate the apparent crashes when installing new maps due to excessive memory use
• Much, MUCH, quicker installation times for new maps
• Much less battery power used when installing new maps
• Simpler code in Bit Map means easier maintenance of the application which means fewer bugs

Disadvantages

There are a small number of minor disadvantages to this solution, however we believe that the advantages makes it well worthwhile.  The disadvantages are:

• Most common image file formats will require processing on the desktop/laptop before being installed into Bit Map, and can no longer be installed directly.
• Requires additional (but free) software to be installed on the desktop/laptop, and for this to be available.  Many users have this software already, but others will need to download and install it.