GIS for Environmental Science ENSC 3603 Class 7 2/03/09

Today's Objectives Quiz GIS Data GeoStor Quick Start Guide NRCS Web Soil Survey Vector Data ArcGis, ArcCatalog

GIS Data GeoStor 5 quick start guide NRCS Web Soil Survey http://www.geostor.arkansas.gov/Portal/ptk?command=quickstarthelp.jsp NRCS Web Soil Survey http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

Data Thematic Layers A GIS stores information about the world as a collection of thematic layers that can be linked together by geography.

Data Geographic data record the locations and characteristics of natural features or human activities that occur on or near the Earths surface. Data Types: Vector Raster Surface

Vector Data Vector Data: A conceptual representation of geographic features. Vector Data Model: Object based approach to represent discrete objects. Vector Data Model Concepts use graphical elements: Points Lines or arcs Polygons or areas These are also known as Feature Classes

Reality as Vector Data Points (Man-holes) Lines (Roads, Sewer lines) Real-World entities are abstracted into three basic shapes Points (Man-holes) Lines (Roads, Sewer lines) Polygons (Wetlands, Fields, Buildings)

Vector Data Point, Line and Polygon entities.

Vector Data Points: Chicken houses in Washington County

Vector Data Line: Washington County Roads

Vector Data Polygon: Washington County Soil Series

Vector Data Converted to Vector data Structure Raster data Structure

Vector Data Feature classes pertain to a particular theme such as vegetation, land parcels, drainage and transportation etc. Feature classes are organized into layers Layers only have one type of graphical element.

Vector Data Representing vector data differently at different scales: Cartographic generalization – line and area objects are represented by more coordinates at a large scale than at a small scale. Cartographic symbolization – Vector data are represented by different symbols that visually distinguish them from one another

Vector Data Topology: Spatial relationships Adjacency: neighborhood Containment: Inclusion of one spatial object within another Connectivity: Linkages among spatial objects

Vector Data Topology: Spatial relationships Adjacency: neighborhood Polygon C is Adjacent to Polygons B and D

Vector Data Topology: Spatial relationships Containment: Inclusion of one spatial object within another. Polygon A is Contained within Polygon B

Vector Data Topology: Spatial relationships Connectivity: Linkages among spatial objects. Point A is Connected to Point B A B

Vector Data Vector-based GIS Data-Processing: Input Analysis Output

Vector Data Input functions Digitizing tables Image scanning Importing data

Vector Data Data input functions: Acquisition by digitizing, purchasing, collecting new data by GPS, surveying or photogrammetric and remote sensing methods Editing to clean and inspect data. Formatting or translating to convert data to a specific physical database format. Linking graphical data to associated attribute data.

Vector Data Analysis functions: Nontopological Analysis: Attribute database query Structured Query Language (SQL) Address geocoding Or Address matching, TIGER files Area Calculation Statistical computation Mean, max, min and standard deviation computed for items in attribute tables.

Attribute database query, Structured Query Language (SQL)

Attribute database query, Structured Query Language (SQL) Map Result

Geocoding Database of address used to Map locations on a map.                                                                                                             Database of address used to Map locations on a map. Mapquest uses Geocoding to find locations.

Statistical computation, Mean, max, min and standard deviation computed for items in attribute tables Field F1 Soil pH

Vector Data Topological Analysis Layer-based Analysis Reclassification Aims to reduce categories of attribute data Layer-based Overlay analysis Topological Overlay Operators for polygon on polygon UNION: Keeps all area in both layers INTERSECT: Keeps only parts of the first layer falling within the second layer IDENTITY: keeps all layer features CLIP: Cuts out a piece of the first layer based on the second ERASECOV: erase part of first layer based on the second SPLIT: divides the first layer based on the second Network analysis

Vector Data Network analysis Linear features that are interconnected Examples, highways, railways, rivers transit routes utility distribution systems. Example problem: Find shortest route between two points. Line segments and junctions can have resistance.

Vector Data River Network

Vector Data Feature-based analysis A Buffer is a zone with a specified width that surrounds a spatial feature. Buffering Used for neighborhood analysis Feature-based overlay analysis Example, point in polygon

Vector Data Buffering around a point Buffering around lines

Vector Data Overlay analysis Represents the world in layers Combines human/social with environmental Data must be measured, generalized, and quantified Both visual and analytical analysis Types Visual, Boolean, Arithmetic

Vector Data Output Functions Vector map Composition Graduated Symbols Graduated Colors Charts Contour Lines 3-D Perspective Views Vector-raster conversion

Class Project A 200 word statement describing a problem to be addressed by the project. Include an: Introduction Objectives Methods – Data, Software, Analysis References Example found at: http://www.uark.edu/depts/agronomy/farm/GISFES09/GISFES09.HTML

For Next time Chapter 5 in Lo (2007) Project proposal due February 5th ESRI Module 2 due

"Focus not on the commotion around you, but the opportunity ahead of you." - Arnold Palmer "Achievement is largely the product of steadily raising one's levels of aspiration and expectation." - Jack Nicklaus