introduction to spatial information technologies in the earth sciences miles logsdon...

Introduction to Spatial Information Technologies

in the Earth Sciences

Miles Logsdonmlog@u.washington.eduhttp://faculty.washington.edu/~mlog Or http://sal.ocean.washington.edu/people

ORWhat is GIS/RS and what can it do for me?

OR

Why is Miles on the faculty in this College?

“Our” agenda today

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

Our collectionPacific Northeast, Apr – Sep, 1999 - 2002

Flying