Also, much public information in a nation may be unavailable from outside the country.
This is why most intelligence services attach members to foreign service offices.
Ordinary facts like the lunar phase on particular days or the ballistic range of common military weapons are also very valuable to planning, and are habitually collected in an intelligence library.
A great deal of useful intelligence can be gathered from photointerpretation of detailed high-altitude pictures of a country.
In response to the information requirements, analysts examine existing information, identifying gaps in the available knowledge.Operational tier is below strategic level of leadership and refers to the design of practical manifestation.Tactical intelligence is focused on support to operations at the tactical level and would be attached to the battlegroup.To provide an analysis, the commander's information requirements are first identified, which are then incorporated into intelligence collection, analysis, and dissemination.Areas of study may include the operational environment, hostile, friendly and neutral forces, the civilian population in an area of combat operations, and other broader areas of interest.