on some fundamental geographical concepts
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On Some Fundamental Geographical Concepts. 176B Lecture 3. 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 - PowerPoint PPT PresentationTRANSCRIPT
On Some Fundamental Geographical Concepts
176B Lecture 3
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
The mosque floor
Geographic primitives
• G = g (x, y, z, s, A, t)
• [x, y, z] = f(d• Geography also highly
dependent upon model
UCSBUCSBLat: 34.4087 Lon: -119.8447Lat: 34.4087 Lon: -119.8447
Projection, datum etc. for a 7.5 min quad
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!
Orthorectification
Georegistration: Control
Georectification
Conflation
Address matching
2123 South Main St.AnywhereCA 93901
4,312,205mN623,864mE
15N
Geographic information fundamentals
1. Volume
2. Dimensionality
3. Continuity
Volume
• 1 meter pixel
• 24 bit depth (8 bit R, 8 bit G, 8 bit B)
• California 3rd largest State A=158,706 square miles
• A= 411,046,653,039 square meters
• N=9.865x10^10 bytes
• 98 gigabyte image
Volume Issues: Tiles and Pyramids
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}
Areas are lines are points are coordinates
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
Field vs. Feature (object)
Fields are often rasters
Air Photos
Discontinuous irregular rasters: resampling
1929
Features are often vectors
Properties of Features
• Size
• Distribution/density
• Shape
• Scale
• Orientation
Size: Resolution and Extent
10cm, 25cm, 50cm, 1m
Resels: Non-uniform Support
Data structure conversion
Distribution
Geographical Clustering
Clusters on points/networks
Shape
Shape vs. Support
Shape measures/analysis
Scale: RF vs. Detail
Santa Barbara
Scaling behavior
Orientation: Objects & Frame
Tobler’s 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
Geographical relations
• Among features– Contains/overlaps/intersects
– Contiguity/Adjacency
– Proximity
– Trajectory
• Within fields– Neighborhood relation
– Pattern
– Process
Vector polygon overlay
O =
Raster overlay
01
& =
Buffering
Pattern
Pattern (Fourier) Analysis
Contiguity
http://www.clearproject.net/chapter10fig5.JPG (Clear Lake, Iowa)
Semivariogram
Most important, process…
•G = g (x, y, z, s, A, t)
t0 t1 t2 t3
Strands
Time-Space dynamics
Dynamics
1930 1950 1970 1980 1990
FROM
TO
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.