Regions
This presentation is the property of its rightful owner.
Sponsored Links
1 / 17

Regions PowerPoint PPT Presentation


  • 110 Views
  • Uploaded on
  • Presentation posted in: General

Regions. Chapter 15. Introduction. Regions are higher level objects built on tip of simple arcs and polygons. Regions are organized into region layers or subclasses. Region consists of polygons that may or may not be connected spatially. Regions of different subclasses may overlap,.

Download Presentation

Regions

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Regions

Regions

Chapter 15


Introduction

Introduction

  • Regions are higher level objects built on tip of simple arcs and polygons.

  • Regions are organized into region layers or subclasses.

  • Region consists of polygons that may or may not be connected spatially.

  • Regions of different subclasses may overlap,


Introduction1

Introduction

  • Corresponds to concept of geographic regions

  • Ethnic, linguistic, ecologic regions.

  • May overlap and include spatially joint or disjoint areas.

  • Vector data!


Geographic regions

Geographic Regions

  • Uniform regions are a geographic area with similar characteristics.

  • Example, uniform landform regions or uniform vegetation, etc.

  • Uniform regions defined by multiple themes

  • Omernik’s ecoregions: land use, potential natural vegetation, land surface form, soils and other supporting data.


Hierarchical regions

Hierarchical Regions

  • Hierarchical regions represent different spatial scales of a hierarchy.

  • Census data compiled by state, county, census tract, block group, and block.

  • USGS hydrologic units organized in nested hierarchy: regions, sub-regions, accounting units, and cataloging units.


Hierarchical regions1

Hierarchical Regions

  • Ecological units are more complex examples of hierarchical regions: ecoregion, subregion, landscape, and land unit.

    • Climate and landform define ecoregion and subregion boundaries.

    • Relief, geologic parent materials, and potential natural communities + climate and landform define landscape boundaries.

    • Topography, soil characteristics, and plant associations + landscape define land units.

  • Canadian ecological land classification


Applications of the regions data model

Applications of the Regions Data Model

  • Building geographic regions

    • Either polygons or regions

    • Use maps of ecological units to create region subclasses for integrated coverage.

  • Advantages

    • Nested, overlapped and disjoint

    • Simple management

    • More efficient query and analysis


Applications of the regions data model1

Applications of the Regions Data Model

Disadvantages

  • Requires large storage and extra processing time

  • More difficult to revise or update (must rebuild entire integrated coverage

  • More difficult to manipulate (errors in clip, erase, etc)


Incorporating spatial scales into gis analysis

Incorporating Spatial Scales into GIS Analysis

  • Spatial scale is not same as maps scale, rather size relationship.

  • Studies of Ecosystems

    • places where life forms and environment interact

    • structure and function affected by environmental and biological factors including climate, geology, soils and flora


Incorporating spatial scales into gis analysis1

Incorporating Spatial Scales into GIS Analysis

  • Studies of Ecosystems

    • hierarchy theory in ecology has emphasized that ecosystems and their underlying biophysical environments occur in a spatial hierarchy, with smaller ecosystems embedded in larger ones

    • conditions or processes of larger ecosystems can affect or constrain smaller ecosystems


Incorporating spatial scales into gis analysis2

Incorporating Spatial Scales into GIS Analysis

  • Studies of Ecosystems

    • For example, logging operations on upper slopes of an ecological unit will likely affect streams and riparian habitats in downslope smaller units.

    • At the same time pins in a snow-pine forest landscape convert solar radiation into sensible heat, which moves to the snow cover and melts it faster than would happen in a wholly snow covered or wholly forested basin.


Modifiable area unit problem

Modifiable Area Unit Problem

  • Modifiable Area Unit Problem (MAUP) addresses the ‘modifiable’ nature of area units used in spatial analysis and the influence it has on the analysis and modeling results.

    • aggregation is usually stronger correlation, but unpredictable

    • better to report at different levels


Create regions

Create Regions

  • Similar to polygon shapefiles in ArcView

  • Created in several ways

    • from existing arcs or polygons

    • data conversion methods

    • related table

    • regions-based commands


Create regions1

Create Regions

  • Use polygons, not arcs if possible due to common boundaries.

  • Can be noncontiguous or contiguous

  • Both function the same but fewer records for noncontiguous

  • Select polygons and MAKEREGION

  • Vector Product Format (VPF) imported to ARC/INFO are example of data conversion method.


Create regions2

Create Regions

  • Create regions by using a related table

  • Requires subclass in table

  • REGIONJOIN

  • Region-based commands

    • DROPFEATURES, REGIONPOLY

  • Attribute management

    • separate, relatable

    • all.patveg


Regions based query and overlay

Regions-Based Query and Overlay

  • Will not detail

  • Commands which can perform overlay, query and creation of region subclasses.

  • Differences in region-based operations

    • limited to polygon coverages

    • use logical operations (AND, OR, XOR, and NOT) rather than UNION, INTERSECT, and IDENTIFY

    • ability to weight influence for snapping


  • Login