Understanding Urban Terrain

1. UnderstandingUrban Terrain

2. Six Fundamental Differences Decentralized Control Communications are frequently restricted and intermittent Requires centralized planning and focus Presence of a civilian population Is always a factor Uneven ambient light Glaring lights and harsh shadows Many surfaces are highly reflective Night vision nearly impossible • Defensive Advantage • Defender enjoys cover and concealment • Avenues of approach are highly predictable • Three-Dimensional • Buildings are hollow and multi-story • Some buildings have intrinsic value • Vertical avenues of approach and escape • Short-range engagements • Typical engagement is less than seven yards • Targets are fleeting and line of sight is restricted

3. 0100 0200 0300 0400 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 Urban Activity Levels Level of activity is somewhat predictable by time of day Number of Events 2200-2400 0500-0700 Time

4. Understanding Urban TerrainPublic Land Survey System • Originated by Thomas Jefferson in 1785 • Includes private land that has been sold • >1.5 billion acres have been surveyed • Used to divide public lands into rectangles • Townships—6 square miles • Sections—1 square mile(640 acres) • Subdivisions—anything less than a section • Half section, quarter section, quarter-quarter section, etc. 1 Mile(640 Acres)

5. Understanding Urban TerrainCity Streets Range line • Conventions • Street numbers • Odd—north and west • Even—south and east • Base line • Central or Center • Main • Midway • Range line • Meridian • Principal 100N→ Base line ←100S ←100W 100E→ 200E→ ~1/8th Mile

6. Sociological Influences • Age • The 100 year old house is an anomaly. The "lifespan" for houses is ~73 years • 43+% have been built since 1970 and about 70% of the 110 million houses in the USA will be around at least another twenty years • Family • Size and idea offamily has impactedsize and construction • Societal shifts • Agriculture to industryto information • Crime, congestion, safety(reversed floor plans)

7. Technological Influences • Construction materials • Plywood, trusses, metal reinforcements, drywall, pre-hung doors, plastic pipes, zero clearance fireplaces, central air conditioning, manufactured housing • Accessories • Fiber optics, HD TV, intercoms, dishwashers, trash compactors, wireless internet, multiple phones, whole house audio, etc. • Multiple bathrooms and home office now common • Anti-intrusion systems • Floor plans changedto accommodate newtechnologies and life styles

8. Economical Influences • House is single most expensive lifetime investment • House representsperson's "worth" • Great Depression • Smaller houses,row houses andtract housing • Post World War II Boom • Converted row houses, large scale tracts, mass-produced housing • Similar, even identical floor plans • Today • Cottage industries, telecommuting, electronic access • Home offices now becoming a norm

9. Political Influences • Building Codes • First appeared in 1922 • Governs types of construction • Planning and Zoning Ordinances • Four major zones • Residential, industrial,commercial and agricultural • Divided still further into types of each • Results in clusters oftypes of buildings • Adjacent attributes oftenapply to target

10. Environmental Influences • Every house is a "mini-environment" (climate) • Conditioned air, water storage and drainage, protection from elements, etc. • Fire • Protection is paramount • Primary impetus for building codes • Water • Protection from precipitation • Protection from ground water • Water kept inside for drinkingwashing, eating, cooking, etc. • Wind • Affects building codes and design • Gravity • The ubiquitous force to which all buildings eventually succumb • Strongly influences construction and provides reliable clues for floor plans— especially weight over distance (span)

11. Single Story Multi-Story Front side is “1 Side” “Rear Five” “Front Five” Number System E 1 2 3 D 1 2 3 3 1 2 3 C 2 4 1 2 3 B 1 2 3 A 4 1 1 Left to RightBottom to Top Immediate Deployments

12. NAVIGATION • Cardinal Directions (most well known) • Awkward in city, compasses affected by magnetic fields and steel objects • Shift from a known point (common) • Uses prominent terrain features as steering marks • Requires prior knowledge or detailed directions • Grid System (MGRS, Thomas Guide and others) • Effective over distance but requires map and ineffective for micro-terrain • Numbering System (Common tactical “work around”) • Highly effective for micro-terrain, inappropriate for longer distances

13. Questions?