I was asked in another forum how to improove the picture quality of some maps created from online sources.
The user had OSM maps which are basically completely white in the background and most tracks/roads were shown in pastell colors, making it really hard to see on a sunny day in the car.
So I try to make it as easy as possible for everyone
First we need to talk about some basics:
It is not possible to directly edit a OZFX map, you can only edit the image used to create the acual map!
One thing you'll notice when using aps from Google or other sources like Nearmap is that you end up with many tiles - depending on the zoom level and area it might be more than a few hundred.
With only Ozi and the Ozi tools at hand you will be a bit lost in terms of editing.
To overcome this I use Global Mapper and Photoshop CS5, both in the 64bit version for good reason.
Some might have downloaded one of my maps for the Grampians, so I use them to explain.
In zoom level 15 there are already about 5000 tiles to consider, in level 17 over 50.000 or about 1.6GB !!
I use Global mapper to combine the single tiles into one big PNG map, saving the projection and other vital info as well.
As a necessary step for later use I also export the map into the ECW format, again with all world and projection files - you will know later why I did this extra step!
After that the image is opened in Photshop and necessary adjustments are made.
Depending on the quality you need you could now save the image in JPG to save some space, but I would stick to PNG.
There is no need to re-calibrate the image, you only needto copy the word- and projection file with the same name as the new image!
Or of course you keep the same filename and work with a backup of the PNG map - your choice
Now the intersting part: you can not directly import a PNG map into Ozi.
So how the hell to we avoid searching for the map details and to calibrate it all again in Ozi if there is no .map file?
Simple Both maps we created with Global Mapper in the step before are identical, except for the type of image and how the RAM is used.
So we imoprt the ECW map into Ozi, resulting in a .map file for the use with the ECW map.
Open this .map with an editor file and change the filename in Line 3 to the PNG map.
E.g.: the PNG map was named "testmap1.png" and the ECW file "testmap2.ecw", you will change the line 3 in the .map file from "####testmap2.ecw" to "testmap1.png".
You should also change the .map filename to the same so it is easier to find corresponding files in your collection.
The #### is the path to the file as generated by Ozi - you can remove that and only keep the actual filename - this way Ozi looks in the same folder for the map and not inside the folder specified.
Don't even bother to load a big PNG map now into OZI!! You are likely to wait for ages or encouter a crash if your machine has not enough RAM to handle the file.
Now use Img2ozf to generate the OZFX map from the PNG map.
Depending on the size this step can take quite a while.
It helps if can reduce the colors to 48 in the earlier steps with Photoshop as the resulting file will be much smaller.
Img2ozf will do it for you too, but I found the results from Photshop much better in terms of quality.
If you are happy with the result you can delete the source files after you confirmed the map is properly calibrated.