Basic Spatial Analysis Tools Queries Spatial Joins Map

Basic Spatial Analysis Tools Queries Spatial Joins Map Overlays Buffers © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 1

Queries § Attribute Queries v Select spatial features based on attribute information. Ø e. g. Find all the Canadian cities with over 1 million inhabitants. § Spatial Queries v Select spatial features based on their location relationships. Ø © J. M. Piwowar e. g. Find all the Canadian cities within 100 km of the U. S. border. Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 2

Spatial Queries § Spatial queries in Arc. GIS: v intersect … v are within a distance of … v completely contain … v are completely within … v have their centre in … v share a line segment with … v touch the boundary of … v are identical to … v are crossed by the outline of … v contain … v are contained by … © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 3

Spatial Joins § Joins spatial features based on their relative locations. v Attributes from the source layer are processed and added to the destination layer. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 4

Spatial Joins § Simple Joins v An object in the source layer corresponds to one (or more) objects in the destination layer. v All the attributes from the source layer are appended to the destination layer. v e. g. To help understand the incidence of crime in a city, we might join the crime locations (points) to neighbourhoods (areas). © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 5

Spatial Joins v Identifies the closest object in the source layer to selected object(s) in the destination layer. v All the attributes from the closest object, plus a distance field to show close they are, are transferred to the selected object(s) in the destination layer. v e. g. Join the nearest prairie dog town to the Frenchman River. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 6 Davis, B. E. , 2001. GIS: A Visual Approach (2 nd ed. ). Albany, NY: On. Word Press. § Distance Joins

Spatial Joins v Identifies the closest object(s) in the source layer to selected object(s) in the destination layer. v The numeric attributes from the closest object(s) are summarized and transferred to the selected object(s) in the destination layer. Ø maximum, minimum, mean, standard deviation, average, etc. v e. g. What is the average population of the prairie dog towns within 1 km of the Frenchman River? © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 7 Davis, B. E. , 2001. GIS: A Visual Approach (2 nd ed. ). Albany, NY: On. Word Press. § Summarized Joins

§ Combines spatially coincident features from different layers to create new features. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 8 Chrisman, 1997. Exploring Geographic Information Systems. New York : Wiley. Map Overlays

Map Overlay v A resort is interested in buying new forest areas to extend the scenic forest drive. "Where are the forest areas OR areas within the resort? " © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 9 Heywood et al. , 1998. An Introduction to Geographical Information Systems. Prentice Hall § Union Overlay

Map Overlay v Where are the areas of forest within the resort area? © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 10 Heywood et al. , 1998. An Introduction to Geographical Information Systems. Prentice Hall § Intersect Overlay

Map Overlay v What is the percentage of the resort area covered by forest? You need to first trim the forest cover to the polygon of the resort. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 11 Heywood et al. , 1998. An Introduction to Geographical Information Systems. Prentice Hall § Clip Overlay

Map Overlay § Arc. GIS Help: v Overlay analysis © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 12

§ Creates areas by extending outward (or inward) a specified distance from point, line, or polygon features. © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 13 Davis, B. E. , 2001. GIS: A Visual Approach (2 nd ed. ). Albany, NY: On. Word Press. Buffers

Buffers § Arc. GIS Help: v Buffer (Analysis) © J. M. Piwowar Geog 409: Advanced Spatial Analysis & Modelling Basic Spatial Analysis Tools 14