Department of Geography and Urban Studies, Temple University GUS 02650465 Applications in GISGeograp

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Department of Geography and Urban Studies, Temple
UniversityGUS 0265/0465Applications in
GIS/Geographic Data Analysis
Lecture 7 Case Study Interpolation of Glacier
Elevation and Analysis of Glacier Area and Volume
Change
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Purpose

• To create a spatio-temporal glacier database to
  support glacier change analysis
• To integrate various historic and contemporary
  data sources on glaciers
• Issues
• Representation of 2-D and 3-D glacier geometry
• Representation of glaciers at different times
• Support for multi-path data retrieval (by
  glacier, location, time)
• Integration of data with varying scales and data
  quality

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Pilot Study Mount Rainier, Washington
Mount Rainier National Park
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Spatial Data Layers
Glacier Extent
Debris Extent
Original Contour
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Spatial Data Layers
Appended Contour
Elevation Points
Glacier Surface
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Spatial Data Layers
Glacier Slope
Glacier Hillshade
Glacier Aspect
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Spatial Data Layers
Terminus Position (detail)
Terminus Position
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Interpolation Trend vs. IDW
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Interpolation Kriging vs. Spline
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Interpolation Spline Weighting
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Managing the Temporal Component of the Spatial
Data
The Snapshot Approach
tn
t1
Time
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Managing the Temporal Component of the Attribute
Data

• The time-normalization approach to representing
  time in the relational data model (Navathe and
  Ahmed, 1993)
• Define three types of attribute data
• Feature-based data
• Glacier-based, time-dependent data
• Glacier-Based, time-independent data

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Feature Based Data

• Data that describe the properties of a single
  feature (i.e. individual polygon) of a glacier at
  a given time of record

Carbon Glacier, 1913
Carbon Glacier, 1913 Polygon Attribute Table
ZONE
M_ELEV
METAKEY
LENGTH
ablation
2038
1814
1020201913
accum.
2809
2683
1020201913
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Glacier Based, Time Dependent Data

• Data that describe the properties of an entire,
  individual glacier that vary over time

Carbon Glacier, 1913
Morphology Table
ELA
AAR
WGMS
METAKEY
NAME
YEAR
2136
0.68
1020271913
102027
Nisqually
1913
2251
0.46
1020201913
102020 13
Carbon
1913
2059
0.55
1020201971
102020
Carbon
1971
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Glacier Based, Time Independent Data

• Data that describe the properties of an entire,
  individual glacier that remain invariant over time

Carbon Glacier, all times
Location Table
STATE
RANGE
WGMS
MOUNT
NAME
WA
Cascade
Mt. Rainier
102027
Tahoma
WA
Cascade
Mt. Rainier
102020
Carbon
WA
Cascade
Mt. Rainier
102025
Cowlitz
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Relational Schema
Carbon Glacier, 1913 Polygon Attribute Table
ZONE
M_ELEV
METAKEY
LENGTH
ablation
2038
1814
1020201913
accum.
2809
2683
1020201913
Morphology Table
ELA
AAR
WGMS
METAKEY
NAME
YEAR
2136
0.68
1020271913
102027
Nisqually
1913
2251
0.46
1020201913
102020 13
Carbon
1913
2059
0.55
1020201971
102020
Carbon
1971
Location Table
STATE
RANGE
WGMS
MOUNT
NAME
WA
Cascade
Mt. Rainier
102027
Tahoma
WA
Cascade
Mt. Rainier
102020
Carbon
WA
Cascade
Mt. Rainier
102025
Cowlitz
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Glacier Area Change 1913 1971
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Calculating Glacier Volume
Glacier Surface Layer
Basal Topography Layer
Glacier Isopach Layer
--

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Calculating Glacier Volume
Carbon Glacier, 1971 Glacier Isopach Data Layer
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Calculating Glacier Volume
Grid Attribute Table for a Glacier Isopach Layer
K
? Tj Aj Cj
V
j 1
COUNT
THICKNESS
Where V is the glacier volume K is the total
number of records in the grid attribute table T
is the THICKNESS value of record j A is the
area of a grid cell (400 m2) C is the COUNT
value of record j.
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10
17
14
12
17
36
20
23
21
56
33
45
34
14
37
67
39
34
42
59
45

K
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Glacier Area and Volume Change, 1913 - 1971
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Data Quality A Comparison
Our 1971 Area and Volume Calculation Results
Versus Driedger and Kennard (1986)
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Data Quality Area Measurements
Surveying Errors
Digitizing Consistency Errors
Registration Errors
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Data Quality Volume Measurements
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Data Quality Volume Measurements
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Data Quality Volume Measurements
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Data Quality Metadata

• Buyer Beware!
• Maintain metadata table (Glacier Based, Time
  Dependent)
• Map Quality
• Survey Date
• Person Digitizing
• Date of Data Digitization