01 How do I support with symbol tables?

Of course we are glad about help – especially concerning the numerous symbol tables. But there are some things to keep in mind regarding this.

  • sources/license information – licence.file
  • symbol files
  • logo file
  • filenames
  • special features of file names – config.file
  • meta data – metadata.file

which I will describe in more detail below.

Finally, put all the files into a ZIP archive file and send it to us, for example to geocache.wizard [at] gmail.com.

For the pros, there is also the option to directly add the symbol table to the app via github and use it to make all changes. This is described here: https://blog.gcwizard.net/manual/uncategorized/04-how-do-i-add-symbol-tables-directly-to-the-gc-wizard-codebase-via-github/

Sources for the symbol tables

The sources for the symbols should be freely available or there must be explicit permission to use these symbols. The best source for this is Wikipedia or its media repository, Wikimedia Commons. Furthermore, we have permission to use the old myGEOtools tables. There are certainly a number more possible sources.

NO source is kryptografie.de, where we unfortunately got an explicit refusal to cooperate!

Please write the source information in a text file licence.file, which saves with the symbols. The most important information are:

  • Name of the author
  • Link to the source
  • Type of license – e.g. GPL, CC-BY-SA 3.0, CC BY-NC-SA 4.0, Personal Use, non commercial , SIL OPEN FONT LICENSE Version 1.1, Apache License Version 2.0, etc.


  • The images are saved as PNG files.
  • The images are optimally 150×150 pixels in size. In any case, it is important that the height is maintained. If the original source does not provide this resolution, there is nothing you can do, of course. The choice of colors is also important. If black and white is sufficient, you should leave it at that. This saves storage space.
  • Please make sure that the symbols are aligned evenly, so that they look orderly in the overall picture – and not one symbol sticks to the right edge and the next one to the top, etc.
  • If you have the symbols as TrueType fonts, there is an elegant solution to export this font to PNG files. This is described here: https://blog.gcwizard.net/manual/uncategorized/03-how-do-i-convert-truetype-fonts-to-symbols/
  • It would also be nice if the images had a transparent background. This would make it easier to change the design later, when the icons should be highlighted with a different color. But this is not planned at the moment. That’s why it’s not a problem if you provide the symbol images with a white background. Graphically inexperienced people often have a hard time with this step and then shy away from all the work. So please don’t let this discourage you, this is a nice-to-have. However, you can simplify this work with Irfan View. This is described here: https://blog.gcwizard.net/manual/uncategorized/02-how-do-i-optimize-the-file-size-and-color-depth-of-symbols-with-irfanview/

Logo file

So that the symbol table can also be recognized, each symbol table needs a logo. Please choose a meaningful symbol file and copy it and rename it to logo.png.

File name

The filename should indicate what the symbol represents.

  • For lower case letters an “_” is set in front of the letter.
  • For special characters, the corresponding English name is used. E.g. ampersand, degree, percent, …The current list of directly supported special characters is available on github.
    So A.png, _x.png, _ch.png, SCH.png, 0.png, 1000.png, percent.png, UE_umlaut, U_circumflex.png, etc.
  • If you need new file names or other special features, another file is required: config.file

Special features of the file names – config.file

The config.file – a plain text file – describes special actions that are required for a correct display of the symbol table. These actions are

special_mappingsThe symbol file name is associated with a special character.
"special_mappings" : {
"add_h" : "+H"
translateThe name of the symbol file is to be translated.
"translate" : [
translation_prefixIf translations already exist, the appropriate prefix can be specified here.
"case_sensitive" : false,
"translation_prefix "common_color_
"translate" : [
case_sensitiveSymbols are case-sensitive when displayed.
"case_sensitive" : true

Meta data – metadata.file

In this text file further data should be provided to the symbol table. This includes e.g.

  • title/name
  • Description
  • Keywords for the search