While mapping you will come across features that need to be verified from reliable sources. Following are some useful resource:
Official road network of Bangladesh:
Roads and Highway Department Maps: http://www.rhd.gov.bd/RHDMaps/Index.asp
District and Upazila maps of Bangladesh:
Local Government Engineering Department Maps: http://www.lged.gov.bd/ViewMap.aspx
Everything about Bangladesh including reference maps:
National Encyclopedia of Bangladesh: http://www.banglapedia.org/
Bangladesh Post Codes
Bangladesh Post Office: http://www.bangladeshpost.gov.bd/PostCode.asp
Directorate of Secondary and Higher Education: http://www.dshe.gov.bd/
Lists of all Government Health facilities and Institutes can be found from Directorate General of Health Services (DGHS)
Online encyclopedia
District Portals: