Did you want to do this on the field or at home?
Look up QuantumGIS (QGIS) or GRASS for a free app, otherwise ArcGIS is more or less the industry standard for map editing.
Note, there is a pretty high learning curve with these apps but if you're just inserting blocks/symbols into a premade map it shouldn't be too hard.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE