Land cover trends in Metro Vancouver, Canada over 45 years: … · Land cover trends in Metro Vancouver, Canada over 45 years: mapping, analysis, and visualization Scott M. Shupe,

Land cover trends in Metro Vancouver, Canada over 45 years: mapping, analysis, and visualization

Scott M. Shupe, PhDDept of GeographyUniversity of the Fraser ValleyAbbotsford, British Columbia

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Location and Context

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• Presentation Outline

• Location and characteristics of area

• Previous land cover mapping

• Ongoing land cover mapping

• Why land cover maps are needed and howthey are used in research

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• In 45 years (1966 – 2011) population morethan doubled (now > 2.3 million)

- 52% English not mother tongue

• Rapid urban expansion beyond city core- forested slopes of mountains- flatter agricultural plains

• Urbanization impacts water quality, but:- cities are different (urban observatory)- study characteristics of Vancouver LC on

water quality over time

• Shupe (2013) – mapping LC on watershed basis from 1976 - 2000



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• Shupe (2013) – mapping LC on watershed basis from 1976 – 2000. Related LC to historical water quality data



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Name of site

Map of site?

Highlight specific research points and/or impacts, areas of interest, pollution sources, etc.

Historical Watershed Level Analysis of Stream Water across Metro Vancouver

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Research Context

Current and Future LC impact on water quality in Metro Vancouver

• HSBC Water Programme Key Cities

• Working with Earthwatch Institute as part of a global 4 year Freshwater Research program funded by HSBC Bank

• Training HSBC Bank Citizen Scientists to Collect basic water data which will be used with Landsat derived LC data in Vancouver

• Contribute data and knowledge to the global Freshwater Research Program led by Steven Loiselle (Earthwatch, UK.)

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Research Context

Interim map showing current CSL water quality monitoring sites

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Research Context

Why 45 years from 1966 – 2011?

Goals

• Expand the existing 1976 – 2000 land cover trend database

- Use 1966 Canada Land Use Monitoring Program (CLUMP) data from the pioneeringCanada Geographic Information System (CGIS).

- In 2012 created a high quality 2011 Landsat LC data set to be used to back classify (or “improve”) old classifications and help forward classify future maps

• Map and visualize trends in land cover change in additional parts of Metro Van

• Highlight where sensitive ecosystems are being impacted

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Mapping Methods

Mapping

• Reconstruct historical CLUMP datasets (1966-86)

• Create or modify more recent data sets (1993 – 2011)

• Edit the digital maps to create consistent classes over the time period

Analysis

• Land change directions and amounts, particularly in watersheds

• Spatial analysis of land cover and topography (with respect to water issues)

Visualization

• 2-D -> 3-D visualization from different angles to provide info to better understandLC changes

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Mapping MethodologiesInconsistent, ambiguous, or missing data: 1966

OutdoorRecreation:

Urban:Lack of detail Ambiguous

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Mapping MethodologiesInconsistent, ambiguous, or missing data: 2006

• 2006 15 m data provided bygovernment (via contractor)contains ambiguity

HighlyReflective:

Ambiguous

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Mapping MethodologiesInconsistent, ambiguous, or historical data: mixed pixels always a problem

Use spectral classification followed by geospatial data modeling and editing

Simple 1986 example:

1)1986 CLUMP data that does not include detail of urban greenness

2)Classify urban structures in 1986 Landsat

3) Overlay 1) and 2) and maintain only common urban

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Mapping Methodologies

Backclassification

• Can also “improve” 1976 CLUMP data using Landsat MSS imagery (but coarser 60 m resolution data)

• 1966 CLUMP data is more problematic because no satellite data- assume that urbanization is linear and can thus we can “grow” missing green areas in urban areas in 1966 map based upon 1976 data.

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Mapping MethodologiesGood reference data essential: leveraging high resolution imagery backdrop in GIS

2011 Landsat Classification:

1)Unsupervised classification

2)Model with Tasseled Cap greenness & other derivatives

3) Edit using Bing imagery

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Caveat: need to be aware of date of base layer imageryand how licensing agreementsmay affect image availability

2011 Landsat urban classification overlay on Bing imagery in GIS

Use of available high resolution imagery:

- accuracy assessment

- updating 2011 map

- then update older maps where possible

e.g. remove urban in

2000 not present

in 2011

Mapping MethodologiesGood reference data essential: leveraging high resolution imagery

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Analysis and VisualizationWe need to monitor changes in LC with changes in water quality over time:

2000 snapshot of urbanization in selected watersheds

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45 years of urban increase at expense of forest and agriculture

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45 years of urban increase at expense of forest and agriculture

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Analysis and VisualizationMetro Vancouver is undergoing continuous urbanization and land cover change

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Analysis and VisualizationMetro Vancouver is undergoing continuous urbanization and land cover change

1966 Urban Surface

2011 Urban Surface

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SummaryMetro Vancouver is undergoing continuous urbanization and land cover change

Land cover maps over a 45 year period provide essential data that can be related to water quality data from sampling programs

Satellite data essential to land cover mapping

Relatively simple mapping methods: most complexity related to creating consistent land cover classes over time.

Current plans are to map Vancouver land cover for 2013 using new Landsat 8 data and update land cover maps into the future using change mapping techniques.

Acknowledgement: Robert Auffray’s time editing land cover maps in a GIS!

Documents

Land cover trends in Metro Vancouver, Canada over 45 years: … · Land cover trends in Metro Vancouver, Canada over 45 years: mapping, analysis, and visualization Scott M. Shupe,