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Img2ozf

The Img2ozf program converts Image files to the OZF and OZF2 image file formats.

What are the OZF and OZF2 Image Formats

These formats have been developed for use in OziExplorer and OziExplorerCE.

OZF

The OZF format stores the image in scanlines. Each scanline is the full width of the image and is manipulated as a unit.

Advantages

• Small files (if compression option used) which can be paged from the disk.

• Fast Initial Loading

• Small RAM requirement when loaded.

Disadvantages

• For OziExplorerCE the format cannot be used with compression as CE devices do not have enough power to uncompress the image page (screen view) required in real time.

• 75% zoom is not available.

OZF2

The OZF2 format stores the image in tiles, each tile is 64x64 Bytes, each tile can be manipulated as a single unit. Because of this layout zoom levels below 100% cannot be created "on the fly" in real time. To overcome this the zoom levels are created when the image is saved and all the selected zoom levels are stored in the same file.

Advantages

• Contains a separate image for each zoom level which produces images almost as good as the original for each zoom level

• Fast Initial Loading

• Small RAM requirement when loaded

• Each page of the image (the screen view) loads much quicker than the OZF format and can also be buffered, this allows the OZF2 format to be used with compression on CE devices.

Disadvantages

• Zoom levels below 100% cannot be created "on the fly" and must be stored within the format.

• Larger file size because of the extra images required for zooming

Recommendations

Use the OZF2 format for both the PC and CE devices.

The PC can handle the larger file sizes and the nice looking zooms are great.

For CE devices you must use the OZF format without compression or the OZF2 format with compression. The OZF2 format with compression can be actually smaller then the OZF file without compression even though it contains multiple map images.

Do not use the 75% zoom option when creating OZF2 files for CE devices unless you have enough space for the larger file sizes.

Relative File sizes

The demo map. The demo map is a self scanned map with many color variations and does not compress well

• demo1.bmp  937,790

• demo1.ozf  939,354

• demo1.ozf2  1,419,639 (zooms = 75,50,33,20,10,5,2.5)

• demo1.ozf2  1,012,619 (zooms = 50,33,20,10,5,2.5)

• demo1.ozf2  766,756 (zooms = 33,20,10,5,2.5)

Another map. This is a USGS DRG map which is professionally scanned and compresses well.

• o410785b5.tif  3,995,890 (the original maps was reduced to half size)

• o410785b5.ozf  8,470,797

• o410785b5.ozf2  3,933,249  (zooms = 50,33,20,10,5,2.5)

As can be seen by the file sizes the compressed OZF2 file is smaller than the uncompressed OSF file.

Why not just use MrSID or the ECW formats which offer high compression and paging ?

I thought I had better answer this question because someone is sure to ask it.

The ECW format will be supported in OziExplorer in the immediate future.

However the OZF and OZF2 formats were developed for use in OziExplorerCE as well as OziExplorer and there are no Software Development Kits to allow MrSID or ECW to be used in the Windows CE environment. I also doubt that CE devices will have the power to use these formats in the foreseeable future.

Using the Img2Ozf Software

Fields

Source Image Folder - Use the button on the right hand end of the field to select the folder where the image(s) to be converted are located.

Destination Folder - The folder where the converted images are saved. The button with the blue Up arrow will make the folder the same as the Source folder.

Temp File Folder - The conversion process may need to create some temporary files, this specifies the folder where the temporary files are placed.

Compress - Tick this box if you want compression. For use on a PC compression should be used for both the OZF and the OZF2 formats. For CE devices compression should not be used for OZF files but should be used for OZF2 files.

Image Type - Specify if you want to create an OZF2 or OZF file.

Zooms - For OZF2 files only, specify the zoom levels you want in the file. Note the larger zoom levels 75% and 50% will greatly increase the size of the image file and also increase the amount of RAM required to convert and the time needed to convert the image. Only choose the 75% zoom level for smaller files.

Image File List - The list of files which can be converted, you can select as many files in the list as required.

Buttons

Process Image Files to OZF Files - Processes the images.

Abort - Aborts the process. The abort may not be immediate as some parts of the process cannot be interrupted. It is probably better to Kill the process using Windows.

Help - The help is contained in the OziExplorer help file so the OziExplorer help file must be available. Img2ozf.exe should be kept in the oziexplorer folder.

Close - Closes the program.

Notes

If using Windows 95/98 you may have problems converting large files to OZF2, you need as much RAM and free disk space for virtual memory as you can get. Due to the limitations of windows 95/98 even this may not help.

If using NT4 or WIN2000 you need to set up a large amount of virtual memory. The size depends on the size of the file being converted, if the conversion fails make the virtual drive larger. NT usually just keeps going and eventually produces the OZF2 file provided it has enough virtual memory.

If you are having problems converting try without the 75% or 50% zooms ticked.

Conversion of large files can take considerable time.

Image Files Supported

Most of the image file formats used in OziExplorer can be converted.

Color Formats Supported

24Bit color images are not supported, use software like Paint Shop Pro (www.jasc.com) to convert the images to 8bit color mode.

For the OZF2 format any BMP files converted should be in 8bit color mode. All other image formats are automatically converted to 256 color OZF2 files. With compressed OZF2 files there is little to be gained from using 2 color source image files, 2 color files produces zoom level images which are not usable.

For the OZF format 2 color BMP files can be converted to 2 color OZF files. All other image formats are converted to 256 color OZF files.

Therefore to create 2 or 16 color OZF files to make the OZF file smaller you must use 2 or 16 color BMP files as the source files for the conversion.

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