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MEMO -TASK 89.1 <br />The Normalized Difference Vegetation Index (NDVI) has been in use for many years to measure and <br />monitor plant growth (vigor), vegetation cover, and biomass production from multi-spectral satellite data <br />(Jackson and Huete 1991, Jensen 1996, Lillesand and Kiefer 2000). NDVI is derived from the difference <br />between the near-infrared region of the electromagnetic spectrum (e.g. Landsat TM Band 4), and the <br />visible red region (e.g. Landsat TM Band 3) using the following equation: <br />NDVI = <br />TM4 -TM3 <br />TM4 +TM3 <br />A multi-temporal NDVI image produced by the composition of individual date NDVI will be used to <br />provide additional information for the manual photo interpretation of field boundaries on DOQQs as well <br />as in subsequent processing for crop classification (Figure 3). Figure 4 shows the multi-temporal NDVI <br />composite produced from the Landsat imagery. The NDVI-composite/DOQQ resolution merge is <br />presented in Figure 5. <br />May Scene <br />Band TM4 May NDVI <br />Band TM3 TM4-TM3 <br />TM4+TM3 <br />July Scene Multi-Temporal <br />Band TM4 July NDVI NDVI Composite <br />Merged <br />Multi-Temporal <br />~ NDVI/DOOO <br />Composite <br />Band TM3 TM4-TM3 Stack Layers <br />TM4+TM3 r~~ ~~ <br />September Scene Overlay <br />Band TM4 September NDVI <br />High-Resolution <br />DOOOs <br />Band TM3 TM4-TM3 <br />TM4+TM3 <br />Figure 3: Multi-temporal NDVI and overlay with high-resolution DOQQs for <br />interpretation and mapping of irrigated field boundaries. <br />The Tasseled Cap transformation is a technique for compressing spectral data into a few bands (i.e., <br />brightness, greenness, wetness) associated with physical scene characteristics (Grist and Cicone 1984). It <br />was originally constructed for understanding important phenomena of crop development in spectral space <br />(Kauth and Thomas 1976). In this project, an assessment of multi-temporal Tasseled Cap will be made as <br />an additional source of information for discriminating irrigated vs. non-irrigated cover types. <br />Page 8 of 13 ~-~~versfde TecAnafagy, lnc. <br />W:rler Resources Frr~mec.•rng ,end L'nr+surlrn2 <br />