Laserfiche WebLink
<br /> <br />000051 <br /> <br />status of lands within their division. Each office reviews the maps for its <br />area and assigns a unique ID to each field, based upon the township, range, <br />and section number. For many of the fields, crop type information is also <br />specified. A minimum of 15% of the fields on each map must be validated. <br />Many of the maps are 100% field-checked. <br /> <br />When review by the State Engineer's Office has been completed, the <br />maps are returned to D-3744. Based upon this new information, the <br />ARC/INFO database is corrected and any additional data added. Final plots <br />'are prepared and sent to the State Eilgineer's Office. This completes the <br />ARC/lNFO vector database development. <br /> <br />IMAGE PROCESSING STEPS <br /> <br />AlthoughsignificantlYll1ore cQstIy thall MSS(multi-spectral scanner) <br />data, "[M(thematic" mapper} was chosen as the ll1osta,ppropriate data <br />'availablefotthis projecl. Numerous studies have demonstrated. that <br />;:substantially more land cover information can be derived from TM data <br />than fromMSS data (Hopkins et.al.; 1990; Prout and Sutton, 1986; Anuta <br />et.al., 1984). This is primarily attributable to the increased number of <br />:spec:tral bands and increased radiometric sensitivity of TM. As a result of <br />the greater dimensionality of the TM data, the number of separable classes <br />produced is twice that of MSSdata (Anuta et.al., 1984). Imageprocessing <br />steps for. the Upper Colorado Irrigated Lands project are as follows: <br /> <br />1) download TM data from9-track tape <br />2) extract AOI (area of interest) <br />3) edge enhance <br />4) apply Tassel.ed Cap transform <br />5) classify image data <br />()}evaluate signatures <br /> <br />Edge Enhancement <br /> <br />Once the image data have been downloaded and the particular ADI <br />.ef'~:~ct~i"'..;tbe~~taareedgeelll:t~c~d. Leean.d. Pri<;e (l9Q3J h~ve, <br /> <br />~-~~~- <br /> <br />enh~~C~r$~.eKerl1els .(j,~e..wtndioWs)\th'at eff~ctiv~IYJn~rease...the spatial. <br />frequencY' of the data. In doing so, the . edges betWeenhoritogelious groups <br />of pixels are amplified. A low pass 3x3 box filter (Figure 1) was selected for <br />useln this study. This filter produces a "sharper" image with minimal data <br />modification. Unlike edge detectors (zero-sum kernels) however, the edge <br /> <br />5 <br />