© Phil Hurvitz, 2001 1

Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish

Farming by

Phil HurvitzGIS Specialist, UW-College of Forest Resources

Principal, Northwest Geospatial, LLP

presented at

55th Annual ConferencePacific Coast Shellfish Growers Association

with the National Shellfisheries Association -

Pacific Coast Section

West Coast Silverdale Hotel Silverdale, WashingtonSeptember 20-22, 2001

© Phil Hurvitz, 2001 2

Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Overview

• Introduction to GIS technology

• Example of GIS analysis for geoduck biomass estimation on a commercial farm

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Introduction to GIS technology

• What is GIS

• What can GIS do

• What are the essential parts of a GIS

• GIS data & data models

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What is GIS

• GIS is an integrated system for• capture• storage• management• analysis• display

of spatially referenced data

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What is GIS

• Spatially referencing and integrated spatial database for storage of spatial data

• Relational database management system for storage of tabular information about spatial features

• Spatial analysis engine

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What is GIS

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What is GIS

Q: Why should this be important to shellfish growers?

A: All shellfish growing activities are ultimately tied to a location.

GIS links information to specific locations.

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What can GIS do

• Capture, store and manage spatial features• Shellfish bed locations• Biological sampling locations

• Transects• Plots

• Bathymetry• Aquatic vegetation patches• Any other mapped or mapable features

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What can GIS do

• Store and manage spatially referenced data• Shellfish bed types (species, year of planting,

etc.)• Biological sampling measurements

• Biomass, shell length, density, etc.

• Aquatic vegetation type (species, etc.)• Any other measurable data tied to location

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What can GIS do

• Analyze spatially referenced data• Determine areas of treatment• Calculate overlap of areas of mixed treatment• Predict spatial/environmental processes• Integrate and model vast amounts of

information from different sources

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS data models

• Vector data• Point (discrete point features)• Line (linear features or events)• Polygon (bounded areas)

• Raster data• Digital orthophoto; satellite imagery• Digital elevation model

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Raster: scanned & georeferenced image

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Raster: scanned & georeferenced image

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Vector: polygon (geoduck bed boundaries)

bed boundaries

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Vector: polygon (bed boundaries)

information(planting year)tied tolocation

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Vector: line (sampling transects)

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Vector: point (GPS locations)

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Vector: point (biological sampling locations)

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Spatial data tied to location

this point

has these data

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

ArcView GIS demonstration

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

A working GIS integrates five key components:

• methods

• people, and

• data,

• software,

• hardware,

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Example of GIS analysis for geoduck biomass estimation on a commercial farm

• Compare “traditional” method of biomass against spatially explicit method

• Interpolation/prediction of measurements across space

• 3-dimensional visualization of measurements

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Traditional line transect method

• Transects laid out

• 1 m2 plots established at regular interval

• Expansion factor calculated to estimate biomass of entire bed

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Problems with line transect method

• Transects may not capture enough spatial heterogeneity of bed

• Plot arrangement may not be conducive to spatial extrapolation

• Result: underestimation or overestimation of biomass

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Typical transect layout

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS-generated scattered grid layout

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Geoduck counts for 1 m2 plots

Forged* (scattered plots)

Samples: 30 points

• Mean: 23

• Maximum: 47

• Minimum: 3

• Range: 44

• Variance: 178

• Standard Deviation: 13

* random counts {0, 47}

Actual (line transect)

Samples: 30 points

• Mean: 25

• Maximum: 47

• Minimum: 0

• Range: 47

• Variance: 225

• Standard Deviation: 15

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Expanded counts from 1 m2 plots

Area of polygon: 7118 m2

Line transect• Mean count: 25 clams/m2 • 7118 m2 * 25 clams/m2 = 177950 clams on bed

Grid • Mean count: 23 clams/m2 • 7118 m2 * 23 clams/m2 = 163714 clams on bed

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS surface generation technique

• Values are taken from point samples

• Interpolates a surface between points

• Surface indicates trends between and beyond actual samples

• Predicts values where measurements have not been taken

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS surface generation technique

• Values of count of clams per plot

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS surface generation technique

• “Spline” analysis

• Creates a continuous surface based on field measurements

• 1 m2 cell size

• Models variation between measurements

• Assigns interpolated count per cell

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

GIS surface generation technique

• Estimated value per cell is summed

• Estimated count based on surface analysis:160460 clams in entire bed

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Comparison of calculated counts

160460

163714

177950

Estimated Count

Surface

Scattered

Transect

Method

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

What is the benefit of GIS in this example?

• Interpolated surface can tell much more about spatial heterogeneity

• Possible to estimate biomass at location that was not sampled

• Possible to gain integrated understanding of site

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

3D Modeling of Site

• Visualization of biomass across site

• Where are values high and where are values low?

• Why does the variation exist?

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

3D Modeling of Site

• Other contributing environmental effects?

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Introduction to Geographic Information Systems and their Potential Uses as Management Tools in Commercial Shellfish Farming

Questions?

• Contact Phil Hurvitz

phil@nwgeospatial.com