UnderstandingUrban Terrain

Six Fundamental Differences1. Defensive Advantage• Defender enjoys cover and

concealment• Avenues of approach are highly

predictable

2. Three-Dimensional• Buildings are hollow and multi-story• Some buildings have intrinsic value• Vertical avenues of approach and

escape

3. Short-range engagements• Typical engagement is less than seven

yards• Targets are fleeting and line of sight is

restricted

4. Decentralized Control• Communications are frequently

restricted and intermittent• Requires centralized planning and

focus

5. Presence of a civilian population

• Is always a factor

6. Uneven ambient light• Glaring lights and harsh shadows• Many surfaces are highly reflective• Night vision nearly impossible

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)

Understanding Urban TerrainCity Streets

~1/8th Mile

Base line

Rang

e lin

e

Conventions• Street numbers

• Odd—north and west• Even—south and east

• Base line• Central or Center• Main• Midway

• Range line• Meridian• Principal

100E→←100W

100N

→←

100S

200E→

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 of

family has impactedsize and construction

• Societal shifts• Agriculture to industry

to information• Crime, congestion, safety

(reversed floor plans)

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

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

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

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 drinking

washing, 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)

Multi-Story

Number System

2

3

4

Front side is “1 Side”Front side is “1 Side”

Single Story

41

A

B

C

D

E

1 2 3

1 2 3

1 2 3

1 2 3

1 2 3

Left to RightBottom to Top

Immediate Deployments

“Rear Five”

“Front Five”

1

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 marksRequires 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

NAVIGATION

Questions?