This is a list of intelligence gathering disciplines.
Human intelligence—gathered from a person on the ground.
Geospatial intelligence—gathered from satellite, aerial photography, mapping/terrain data
Measurement and signature intelligence:
Open-source intelligence—gathered from open sources.
Can be further segmented by source type; Internet/General, Scientific/Technical and various HUMINT specialties (e.g. trade shows, association meetings, interviews, etc.)
Signals intelligence—gathered from interception of signals
Technical intelligence—gathered from analysis of weapons and equipment used by the armed forces of foreign nations, or environmental conditions.
Cyber Intelligence/Digital Network Intelligence—gathered from cyberspace
Financial intelligence—gathered from analysis of monetary transactions