For sites and databases relevant to Southeast Asian and environmental history
(with a bias towards what I usually read)
Digital Archives and Databases
Cornell University Library Southeast Asia Collections - includes some digitised collections of materials from US Southeast Asian professors at Cornell and also useful as a portal for other Southeast Asia online databases
Delpher - Digitized Dutch books, newspapers and journals including those covering 19th century Dutch East Indies
Digital Islamic Humanities Project - at Brown University
Malay Concordance Project - Digitized Malay manuscripts, including a word search function
National Library of Singapore BookSG - for Singapore and Southeast Asian digitised books, including early surveys of the region and Malay manuscripts from the British Library, and Berlin Library. For early Singapore and Malaya newspapers, check out NewspaperSG
National Library of Indonesia (Perpusnas) - e-resources available to members only
Climate DataBases and Proxy Records
Ways to do climate history, how climate change affects social structures, and more..
Data sets on historical recovery on meteorological data and marine global weather observations
Data Sets for Ice core records, pollen, historical fires and more
Dendrochronology - There is an old world drought atlas, based on data from tree rings.
Past Global Changes - including a global charcoal database (trace evidence of forest clearings through fire, among others), an open access magazine focusing on historical land use and a list of people to contact if you need paleoclimate data
Palynology - pollen analysis helps in the reconstruction of past vegetation cover. Unfortunately, there has not been much sampling done in Southeast Asia, specifically, the best bibliography for the outcome of such research that I can find is here.
Mapping Projects and Digital Tools
Dataquest - Free place to learn basics of Python and R!
Dutch Royal Tropical Institute Digital Map Collection - especially useful for colonial-era maps
KITLV map collection - still under construction and mostly 19th to 20th century Dutch East and West Indies, the Dutch Antilles and parts of Southeast Asia
Open Source Software:
and GEPHI for network analysis
Stanford Digital Humanities Project, including a great one on mapping vice in early 20th century Philippines for Southeast Asianist
Do some environmental good through online mapping here!