On Some Fundamental Geographical Concepts

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On Some Fundamental Geographical Concepts

• 176B Lecture 3

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Nystuen, J. D. (1963) Identification of some
fundamental spatial concepts

• Search for a common geographical terminology to
  eliminate redundancy
• Basics Distance, pattern, relative position,
  site and accessibility
• Advantages of abstract models and assumptions,
  e.g. isotropic surface

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The mosque floor
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Geographic primitives

• G g (x, y, z, s, A, t)
• x, y, z f(l, f, d)
• Geography also highly dependent upon model

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UCSBLat 34.4087 Lon -119.8447
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Projection, datum etc. for a 7.5 min quad
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GIS basic geometric functions

• A GIS package must be able to move between
• map projections
• coordinate systems
• datums
• Ellipsoids
• A GIS must be able to GEORECTIFY
• Not always a simple task!

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Orthorectification
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Georegistration Control
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Georectification
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Conflation
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Address matching
2123 South Main St. Anywhere CA 93901
4,312,205mN 623,864mE 15N
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Geographic information fundamentals

1. Volume
2. Dimensionality
3. Continuity

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Volume

• 1 meter pixel
• 24 bit depth (8 bit R, 8 bit G, 8 bit B)
• California 3rd largest State A158,706 square
  miles
• A 411,046,653,039 square meters
• N9.865x1010 bytes
• 98 gigabyte image

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Volume Issues Tiles and Pyramids
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Dimensionality

• Simple geographic features can be used to build
  more complex ones.
• Areas are made up of lines which are made up of
  points represented by their coordinates.
• Areas Lines Points

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Areas are lines are points are coordinates
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Continuity

• Attributes of the earth fall into different
  spatial behaviors over space and time
• Many phenomena are best treated as continuous
  fields
• E.g. air temperature, atmospheric pressure,
  population density
• Others have distinct spatial extent or edges
• E.g. census tracts, buildings, roads

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Field vs. Feature (object)
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Fields are often rasters
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Air Photos
1929
Discontinuous irregular rasters resampling
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Features are often vectors
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Properties of Features

• Size
• Distribution/density
• Shape
• Scale
• Orientation

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Size Resolution and Extent
10cm, 25cm, 50cm, 1m
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Resels Non-uniform Support
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Data structure conversion
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Distribution
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Geographical Clustering
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Clusters on points/networks
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Shape
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Shape vs. Support
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Shape measures/analysis
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Scale RF vs. Detail
Santa Barbara
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Scaling behavior
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Orientation Objects Frame
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Toblers First Law of Geography

• Everything is related to everything else but
  near things are more related than distant things
  (Tobler, 1970)
• Variation of (x1 x0)2
• Spatial autocorrelation
• Violates assumptions of statistics

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Geographical relations

• Among features
• Contains/overlaps/intersects
• Contiguity/Adjacency
• Proximity
• Trajectory
• Within fields
• Neighborhood relation
• Pattern
• Process

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Vector polygon overlay

O
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Raster overlay
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1


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Buffering
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Pattern
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Pattern (Fourier) Analysis
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Contiguity
http//www.clearproject.net/chapter10fig5.JPG
(Clear Lake, Iowa)
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Semivariogram
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Most important, process

• G g (x, y, z, s, A, t)

t0
t1
t2
t3
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Strands
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Time-Space dynamics
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Dynamics
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Geography

• The study of the earth and its features and of
  the distribution of life on the earth, including
  human life and the effects of human activity.