Rangelands are an important resource to Alberta. Due to their size, mapping
rangeland features is difficult. However, the use of aerial and satellite data for mapping
has increased the area that can be studied at one time. The recent success in applying
hyperspectral data to vegetation mapping has shown promise in rangeland classification.
However, classification mapping of hyperspectral data requires existing data for input
into classification algorithms. The research reported in this thesis focused on acquiring a
seasonal inventory of in-situ reflectance spectra of rangeland plant species (endmembers)
and comparing them to evaluate their separability as an indicator of their suitability for
hyperspectral image classification analysis. The goals of this research also included
determining the separability of species endmembers at different times of the growing
season.
In 2008, reflectance spectra were collected for three shrub species (Artemisia
cana, Symphoricarpos occidentalis, and Rosa acicularis), five rangeland grass species
native to southern Alberta (Koeleria gracilis, Stipa comata, Bouteloua gracilis,
Agropyron smithii, Festuca idahoensis) and one invasive grass species (Agropyron
cristatum). A spectral library, built using the SPECCHIO spectral database software,
was populated using these spectroradiometric measurements with a focus on vegetation
spectra.
Average endmembers of plant spectra acquired during the peak of sample
greenness were compared using three separability measures – normalized Euclidean
distance (NED), correlation separability measure (CSM) and Modified Spectral Angle
Mapper (MSAM) – to establish the degree to which the species were separable. Results
were normalized to values between 0 and 1 and values above the established thresholds
indicate that the species were not separable . The endmembers for Agropyron cristatum,
Agropyron smithii, and Rosa acicularis were not separable using CSM (threshold =
0.992) or MSAM (threshold = 0.970). NED (threshold = 0.950) was best able to separate
species endmembers.
Using reflectance data collected throughout the summer and fall, species
endmembers obtained within two-week periods were analyzed using NED to plot their
separability. As expected, separability of sample species changed as they progressed
through their individual phenological patterns. Spectra collected during different solar
zenith angles were compared to see if they affected the separability measures. Sample
species endmembers were generally separable using NED during the periods in which
they were measured and compared. However, Koeleria gracilis and Festuca idahoensis
endmembers were inseparable from June to mid-August when measurements were taken
at solar zenith angles between 25° – 30° and 45° – 60°. However, between 30° and 45°,
Bouteloua gracilis and Festuca idahoensis endmembers, normally separable during other
solar zenith angles, became spectrally similar during the same sampling period.
Findings suggest that the choice of separability measures is an important factor
when analyzing hyperspectral data. The differences observed in the separability results
over time also suggest that the consideration of phenological patterns in planning data
acquisition for rangeland classification mapping has a high level of importance. / xii, 93 leaves : ill. (some col.) ; 29 cm
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:ALU.w.uleth.ca/dspace#10133/2527 |
| Date | January 2010 |
| Creators | Rolfson, David, University of Lethbridge. Faculty of Arts and Science |
| Contributors | Staenz, Karl, Coburn, Craig |
| Publisher | Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, 2010, Arts and Science, Department of Geography |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | Thesis (University of Lethbridge. Faculty of Arts and Science) |
Page generated in 0.0021 seconds