## Units

### What is a unit?

Meter, centimeter, millimeter, micrometer, light year, etc are units of the category length for example. If you want to add, change or delete untis, edit the textfiles `Installationdirectory/data/units/*.list`

### Description of a file containing units

The "`.list`" files are used to specify units and factors. Empty lines and lines with a leading hash (#) are ignored by the program. The sequence in the GUI appears as you defined them in the "`.list`" files.

### Format of a line

Each token is separated by a colon. Each line must have at least two tokens: "`Name`" and "`Value`". This is the full format:
`Name:Value:Countrycode:Validity:Selection`

### Description of the tokens

`Name`

The name appears in the combo box.

`Value`

The factor of the unit. Basic units like meter, second, watt, kilogramm, etc. should have the factor 1. Here are some examples to show the syntax of valid values:
`1 = 1.0`
`2.45 = 2.45`
`1e-4 = 0.0001`
`2.45e3 = 2450`
`1/2 = 0.5`
`1e-4/9 = 0.00001111...`

`Countrycode`

What countries are using the unit? A little flag shows the country or the countries which are using the unit.
The NC find flags in the file "`lib/flags30x15iso3166.jar`", their code is defined in the ISO 3166 standard. The country code has to be specified in lowercase characters ("de" for Germany). Self created flags can be found in "`installationdirecotry/data/images/flags/Countrycode.png".` Only png is supported.

`Validity`

Set the value of this token to "false", if the unit is old, obsolete, unusual or not valid anymore. The unit will be displayed with a grey textcolor in the combo box. Otherwise a black textcolor is shown. Valid values for the Validity are "true" and "false".

`Selection`

This token will be evaluated if the category will change. Valid values are:
source = unit will be used as source
target = unit will be used as target
source,target = unit will be used as source and target