Albion 6 GIS User Guide > Appendix > APPENDIX A: Scripting in Albion GIS

The following samples demonstrate how to write freeform scripts in Lua. Such scripts are typically used to manipulate data tables.

Format

All of the samples assume that the script is operating on a database record with the following fields and values:

distribution_zone	original_diameter	diameter	material	code
983	0.200	0.150	PVC	HC203

Examples

Copy distribution_zone to original_diameter:

record.original_diameter = record.distribution_zone

original_diameter: 0.200 -> 983

Make diameter 3x original_diameter:

record.diameter = 3 * record.original_diameter

diameter: 0.150 -> 0.600

Combine code and diameter into distribution_zone, formatting diameter to 4 decimal digits

record.distribution_zone = record.code .. string.format( " -- %.4f", record.diameter )

distribution_zone: 983 -> HC203 -- 0.1500

If original_diameter is null, then make diameter -99, otherwise make it original_diameter

if record.original_diameter == nil then record.diameter = -99

else record.diameter = record.original_diameter

end

diameter: 0.150 -> 0.200

Lookup record in foreign database

-- Retrieve a handle to the table named 'othertable', which resides in the database named 'otherdb'

local tab = adb.table( 'otherdb.othertable' )

-- Find the first record in 'othertable' that has its 'material' field value equal to our record's 'material field value.

local mat_record = tab:find_first( 'material', record.material )

-- If such a record exists, then lookup the value of its 'diameter_factor' field.

if mat_record ~= nil then record.diameter = record.original_diameter * mat_record.diameter_factor

else record.diameter = record.original_diameter

end

diameter: 0.150 -> 0.200 (assuming the foreign database existed)

Sample Lua Freeform Scripts