Tamarisk (Tamarix spp., saltcedar) is a well-known invasive phreatophyte introduced from Asia to North America in the 1800s. This report compares the efficacy of Landsat 5 Thematic Mapper (TM5), QuickBird (QB) and EO-1 Hyperion data in discriminating tamarisk populations near De Beque, Colorado, USA. As a result of highly correlated reflectance among the spectral bands provided by each sensor, relatively standard image analysis methods were employed. Multispectral data at high spatial resolution (QB, 2.5 m Ground Spatial Distance or GSD) proved more effective in tamarisk delineation than either multispectral (TM5) or hyperspectral (Hyperion) data at moderate spatial resolution (30 m GSD).
Fi gure 1. M ap of t he M i ssi ssi ppi barri er i sl ands, nort hern G ul f of M exi co. The red st ar i ndi cat es t he l ocat i on of t he U SM G ul f C oast G eospat i al C ent er. Fi gure 2. Seagrass m aps devel oped f rom m osai cs of 1940 and 2007 vert i cal aeri al i m agery. Vari ous t ypes of i m age dat a w ere used i n t he st udy, rangi ng f rom di gi t i zed bl ackandw hi t e phot ographs (e. g. , 1940) t o hyperspect ral i m agery (2007 dat a, C ASI 570 nm band). W here spect ral dat a w ere avai l abl e, seagrass m appi ng w as based sol el y on t he use of greenband dat a (Peneva et al. , 2008). Fi gure 4. R el at i onshi p of seagrass bed areal coverage w i t h t he t ot al l and area of Pet i t Boi s I sl and, 19402007. Fi gure 3. D ecadal changes i n seagrass coverage on t he M i ssi ssi ppi barri er i sl ands. Sam pl i ng error (bars) w as est i m at ed t o be 5%. Island Land Area (ha)
Fi gure 1. M ap of t he M i ssi ssi ppi barri er i sl ands, nort hern G ul f of M exi co. The red st ar i ndi cat es t he l ocat i on of t he U SM G ul f C oast G eospat i al C ent er.
Fi gure 2. Seagrass m aps devel oped f rom m osai cs of 1940 and 2007 vert i cal aeri al i m agery. Vari ous t ypes of i m age dat a w ere used i n t he st udy, rangi ng f rom di gi t i zed bl ackandw hi t e phot ographs (e. g. , 1940) t o hyperspect ral i m agery (2007 dat a, C ASI 570 nm band). W here spect ral dat a w ere avai l abl e, seagrass m appi ng w as based sol el y on t he use of greenband dat a (Peneva et al . , 2008).
Fi gure 4. R el at i onshi p of seagrass bed areal coverage w i t h t he t ot al l and area of Pet i t Boi s I sl and, 19402007.
Fi gure 3. D ecadal changes i n seagrass coverage on t he M i ssi ssi ppi barri er i sl ands. Sam pl i ng error (bars) w as est i m at ed t o be 5% .Island Land Area (ha)
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