Colleagues of mine suggested the following:

François Jacquesson writes: "Si ton correspondant cherche des cartes anciennes ou modernes, il peut trouver à :
https://www.davidrumsey.com/view ; https://zenodo.org/records/3596441#.XsjDX0QzaUl
Il est difficile de dire des choses plus précises parce que la question posée est vaste, mais il peut contacter des géographes spécialistes de l'Himalaya : Olivia Aubriot (https://himalaya.cnrs.fr/spip3/spip.php?article117), Joelle Smadja (https://himalaya.cnrs.fr/spip3/spip.php?article123)."

Felix de Montéty suggests to contact Philip Jagessar (https://www.kcl.ac.uk/people/philip-jagessar), "a geographer who researched the modern and contemporary cartography of India and could certainly help you navigate through the extensive bibliography or get in touch with more specialised colleagues."

Best wishes,
Agnes

Dear all,

Can anyone point out detailed studies on northeastern Indian geography?

More specifically I am looking for studies on

Longitudinal Division of Eastern Himalaya

Barail range

the Brahmaputra alluvial plain

the Karbi-Anglong plateau

the Meghalaya plateau 

Barak plain

Tripura plain

With my best wishes,

Paolo

--

Paolo E. Rosati

PhD in Asian and African Studies

https://uniroma1.academia.edu/paoloerosati/

paoloe.rosati@gmail.com

Mobile/Whatsapp: (+39) 338 73 83 472

-- 
Agnes Korn, PhD habil.
CNRS ; UMR 8041 Centre de recherche sur le monde iranien (CeRMI)
7 rue Guy Môquet
94800 Villejuif
France

agnes.korn@cnrs.fr
https://cermi.cnrs.fr/membres/korn-agnes/