For more advanced users, that want to use Locus also for some specific tasks, like surveyors and others, Locus allow to use custom coordinate system for coordinate transformations.

Currently these systems are used only for display/edit of coordinates, not for map projections. So it's not possible to re-project map to different coordinate system.

For coordinate definition is used configuration file stored in Locus root directory and called config_projections.cfg.

• Description of this file is below: (copy of file header)

config.cfg

#   Configuration file (advanced settings) for Locus application
# allow to specify map projections, based on EPSG code. If you need some
# more specific projection, contact us
# 
# every line should contain syntax and values have to be separated by '|' char
# 
# 'type of definition' | 'EPSG code' | 'name' | 'description' | 'country'
# 
# where 
#   'type of definition' is currently 1
#   'EPSG code' - known code from (eg.) http://spatialreference.org/
#   'name' - visible name
#   'description' - visible description in list
#   'country' - country of usage for sorting in list
# ----------------------------------------------------------------

• So every line must contain only one definition based on EPSG code for now.

Example of file is

# header from above

1|2391|Finland zone 1|EPSG:2391|Finland
1|2392|Finland zone 2|EPSG:2392|Finland
1|2393|Finland Uniform Coordinate System|EPSG:2393|Finland
1|2394|Finland zone 4|EPSG:2394|Finland
1|3067|TM35FIN|EPSG:3067, UTM35 / GRS80|Finland
1|3857|Pseudo-Mercator|EPSG:3857,900913, WGS84 / Sphere|World
1|31467|3-degree Gauss-Kruger zone 3||Germany

• Save file and start Locus
• Set new coordinate system in Menu > Settings > Language & Units > Coordinates type