I've got some GIS data with many data fields for each feature. I'm using Mapshaper to simplify it into a light, lean topojson file.
I want the ID fields of these features in the output to be a modified composite of different fields, for example:
I've tried putting an expression in the export option:
"drop table" "id-field=fieldA+'_'+fieldB"
...but it didn't work. I can't immediately see anything in the command reference to do what I want to do.
For bonus points I'd also like to run an expression over the field to modify it in other ways, for example, one of my fields is a 3-digit number with preceding zeros (e.g.
092) and if possible I'd like to remove these while creating the topojson, e.g. taking
someName and outputting the ID field as
92_someName. If this isn't possible in Mapshaper I can work around it.