Military Geography is a sub-field of geography. In order to understand why it falls under this category, it is important to have a clear understanding of what military geography entails and how it relates to other branches of geography.

1. Definition and Scope of Military Geography:
- Military geography is the study of the spatial aspects of military activities, including the analysis of how geography impacts military operations, strategies, and logistics.
- It involves examining the physical environment, terrain, climate, and other geographical factors that influence military decision-making.
- Military geography also considers the spatial distribution of military assets, such as bases, ports, and supply routes, as well as the geopolitical implications of military actions.

2. Relationship with Major Field of Geography:
- Geography as a major field encompasses various sub-disciplines, such as physical geography, human geography, and environmental geography.
- Military geography is a specialized sub-field that focuses specifically on the spatial aspects of military activities.
- It draws upon the principles and methodologies of these major fields, particularly physical geography (e.g., landforms, weather patterns) and human geography (e.g., population distribution, urban planning).

3. Distinction from Minor Field of Geography:
- A minor field of geography refers to a narrower area of study within a sub-discipline.
- Military geography, although specialized, is considered a sub-field due to its relatively broader scope compared to a minor field.
- While minor fields may focus on specific topics within military geography (e.g., military cartography, military intelligence), military geography itself encompasses a wider range of subjects.

4. Importance and Applications of Military Geography:
- Military geography plays a crucial role in military planning, intelligence gathering, and operational decision-making.
- It helps identify and assess the geographical advantages and challenges of a particular area, influencing the selection of military strategies and tactics.
- Military geography also contributes to understanding the geopolitical dynamics of conflicts and the impact of military activities on the environment.

In conclusion, military geography falls under the category of sub-field in geography due to its specialized focus on the spatial aspects of military activities. While it draws upon the principles of major fields like physical and human geography, its scope is broader than a minor field. Military geography is crucial in military planning and decision-making, as well as in understanding the geopolitical implications of military actions.