Introduction to Spatial Information Technologies in the Earth Sciences Miles Logsdon [email protected]http:// faculty.washington.edu/~mlog Or http://sal.ocean.washington.edu/people OR What is GIS/RS and what can it do for me? OR Why is Miles on the faculty in this College?
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Introduction to Spatial Information Technologies
in the Earth Sciences
Miles [email protected]://faculty.washington.edu/~mlog Or http://sal.ocean.washington.edu/people
What are “spatial information technologies? What is the difference between GIS, Spatial
Analysis, and Spatial Data Analysis? What is the difference between a Spatial
model and a Spatial Explicit Model What is a theoretical basis for the application
of GIS and spatial data analysis in Ecological Studies?
What research “methods” or “tools” directly apply between the two fields?
My agenda
• Show you pretty pictures
• Talk about myself• Justify our time
together• Stop talking - Sooner
or laterSpatial
InformationTechnologies
GIS - GPS – Remote Sensing
Spatial Information Technologies
• Geographic Information Systems – GIS• Global Positioning System – GPS• Remote Sensing and Image Processing - RS
Technologies to help answer:• What is “here”? … give a position • What is “next” to “this”? … given some description• Where are all of the “???” … detecting or finding• What is the spatial pattern of “???”• When “X” occurs here, does “Y” also occur?
GISGeographic Information System
GIS - A system of hardware, software, data, people, organizations and institutional arrangements for collecting, storing, analyzing, and disseminating information about areas of the earth. (Dueker and Kjerne 1989, pp. 7-8)
GIS - The organized activity by which people •Measure aspects of geographic phenomena and processes; •Represent these measurements, usually in a computer database;•Operate upon these representations; and •Transform these representations. (Adapted from Chrisman, 1997)
A KEY POINT: Geo-referenced Data
Suggested Reading
• Chrisman, Nicholas, 1997, “Exploring Geographic Information Systems”, John Wiley & Sons,
• Burrough, P. A., 1986, “Principles of Geographical Information Systems for Land Resources Assessment”, Monographs on Soil and Resources Servey #12, Oxford Science Publications
• Miller, Roberta Balstad, 1996, "Information Technology for Public Policy", in GIS and Environmental Modeling: Progress and Research Issues, editors, Michael F. Goodchild, Louis T. Steyaert, Bradley O. Parks, Carol Johnston, David Maidment, Michael Crane, and Sandi Glendinning, GIS World Books.
• Goodchild, Michael F., "The Spatial Data Infrastructure of Environmental Modeling", in GIS and Environmental Modeling: (see above).
• Faber, G. Brenda, William W. Wallace, Raymond M. P. Miller, "Collaborative Modeling for Environmental Decision Making", proceedings of the GIS'96 Tenth Annual Symposium on Geographic Information Systems, Vancouver, B.C., March 1996.
The larger context
(Chrisman, 1997)
Concept of Spatial Objects
• POINTS
• LINES
• AREA
0 00
00 0 0
01
POINT
1
0
1
11
0 0
00
0
5 5 3
3311 2
LINE
AREA
Raster Data Encoding
Vector Data Encoding
Vector - TopologyObject Spatial Descriptive
1
2 3
45
15
1211
10
123
x1,y1x2,y2x3,y3
123
12
12
12
12
VAR1 VAR2
VAR1 VAR2
VAR1 VAR2
Fnode Tnode x1y1, x2y2
1 2 xxyy, xxyy2 3 xxyy,xxyy
10, 11, 12, 1510, …….
1
2 3
1
2
Vector - TopologyData Relationships are invariant to translation and rotation
Map AlgebraRaster topology
In a raster GIS, cartographic modelingis also named Map Algebra.
Mathematical combinations of raster layers several types of functions: • Local functions – do not consult the 8 neighbors• Focal functions – function on the “kernel” of neighboring cells• Zonal functions – function on cells that test true in a different layer• Global functions – based upon the distribution of “all” cells
Functions can be applied to one or multiple layers
Focal Function: Examples
2 0 1 1
2 3 0 4
2 1 1 2
2 3 3 2
2 0 1 1
2 3 0 4
4 2 2 3
1 1 3 2
•Focal Sum (sum all values in a neighborhood)
=
=
•Focal Mean (moving average all values in a neighborhood)
1.8 1.3 1.5 1.5
2.2 2.0 1.8 1.8
2.2 2.0 2.2 2.3
2.0 2.2 2.3 2.5
(3x3)
(3x3)16 13
17 19
Spatial Data Analysis
The accurate description of data related to a process operating in space, the exploration of patterns and relationships in such data, and the search for explanation of such patterns and relationships
Spatial Analysis vs. Spatial Data Analysis
Spatial Analysis = what is here, and where are all the X’s ???
Spatial Data Analysis = observation data for a process operating in space and methods are used to describe or explain the behavior, and/or relationship with other phenomena.
GPS – Finding distance by measuring
time
X
A B
u
4:00 p.m. >> << 7/100 of a secondafter 4:00
G J K E T Y U O W V W T D H K …
G J K E T Y U O W ...
Receiver:Satellite:
• The precise location is determined by the intersection of 4 spheres of “time”
GPS SV
Satellite Remote Sensing
June 27, 2001
A “zonal” function between 3 raster layers
SeaWifs, April 24, 1999
Thanks to Seelye Martion
PATTERN: (Landscape Ecology)
• Structure = the spatial relationships among the distinctive ecosystems or “elements”
• Function = the interactions among the spatial elements
• Change = the alteration in the structure and function of the ecological mosaic over time
Landscape Structure Physiognomy / Pattern
• Composition = The presence and amount of each element type without spatially explicit measures.– Proportion, richness, evenness, diversity
• Configuration = The physical distribution in space and spatial character of elements.– Isolation, placement, adjacency
• ** some metrics do both **
Types of Metrics
• Area Metrics• Patch Density, Size and Variability• Edge Metrics• Shape Metrics• Core Area Metrics• Nearest-Neighbor Metrics• Diversity Metrics• Contagion and Interspersion Metrics
Represent the Represent the DataData
Explore the DataExplore the Data
Fit a ModelFit a Model
Perform Perform DiagnosticsDiagnostics
Compare the Compare the ModelsModels
Structured Process in Structured Process in GeostatisticsGeostatistics
Introduction to GeostatisticsZ(s)
D • D is the spatial domain or area of interest
• s contains the spatial coordinates
• Z is a value located at the spatial coordinates
{Z(s): s D}Geostatistics: Z random; D fixed, infinite, continuousLattice Models: Z random; D fixed, finite, (ir)regular gridPoint Patterns: Z 1; D random, finite
Merge Bathymetry & Topography
Thanks to David Finlayson
Puget Sound DEM: Resolving Coast Geomorphology
Thanks to David Finlayson
Dec. 1998
June, 1981Classified “land surface” response
Apr May Jun
Jul Aug Sep
Ocean Remote Sensing:
SeaWifs, 1999, 1km monthly mean chlorophyll-a estimates