Transcript Wild Rice Mapping Rice Lake NWR

Josh Knopik, WRS
Jessica Campbell, MGIS
FR 5262
Outline
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Background and Objectives
Data and Materials
Methods
Results
Discussion
Background and Objectives
• USFWS has been monitoring wild rice and
other aquatic vegetative species at Rice Lake
NWR since 1983.
• Wild rice has a cultural significance to local
Native American tribes for harvesting.
• Previous studies have calculated area of wild
rice present on lake.
Background and Objectives (cont.)
• Objective was to conduct an assessment of wild
rice present on lake in 2010.
• Previous assessment was done in 2004.
• Goal was to classify into three classes; mostly
wild rice, open water, and mostly other
vegetative species.
Data and Materials
• Aerial photographs were taken in the summer of
2010, orthorectified, and mosaicked to form a
“complete” picture of the lake.
• Photos were captured in CIR film with three bands;
Red/NIR 850-1100 nm, Green/Red 600-720 nm,
and Blue/Green 500-600 nm and a 0.1m pixel
resolution.
• In late August 2010, 76 reference plots were
collected and in early October, another 24 were
gathered as well.
Data and Materials (cont.)
• Used ERDAS 2010 and ArcGIS 9.3.1 for
classification.
• Took over 200 photos and a half dozen videos
along with reference data plots.
• Report from study in 2004 to compare methods
and remain consistent with previous practices.
Methods
• Unsupervised
Classification
– RGB Clustering
• Layer Stack
Methods (cont.)
• Unsupervised (cont.)
– Image Segmentation
• Convert Feature to Polygon
– In ArcGIS 9.3.1
• Zonal Attributes
Methods (cont.)
• Assessed Means from
Segmented Feature Classes
– Compared each stacked layer and
verify with training data collected
• Supervised Classification
–
Wrote SQL queries to pull polygon
segments that satisfied mean ranges for a
given class.
Methods (cont.)
• Supervised Classification
(cont.)
– Manually reclassified
polygons based off
query results, training
area values, and various
elements of image
interpretation.
– Performed this for all 24
sections of the lake and
then merged features
based on class.
Results
2010
Class
Area %
Acres
Area (m2)
Mostly
Rice
32.9
1,195
4,836,047.8
Mostly
Water
21.5
779
3,154,189.3
Mostly
Other
45.6
1,655
6,696,502.8
²
2010 Analysis
1 Mostly Wild Rice
2 Mostly Water
0
0.25
0.5
1 Mile
3 Mostly Other
Projected in UTM Zone 15N
Results (cont.)
Rice Lake Vegetation
2500
2000
1500
Acres
Rice
Water
Other
1000
500
0
1980
1985
1990
1995
2000
2005
2010
2015
Discussion
• Challenges
– Image Segmentation
– Species with similar spectral signatures
• Accuracy Assessment
– Unable to conduct at this time; no ground data
– Could conduct “expert interpreter” assessment
• Continuing Project…
– Short Term: Texture tool in ERDAS 2010
– Long Term: LiDAR?
Questions?