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<br />I <br /> <br />030042 <br /> <br />INTRODuctION <br /> <br />The primary objective of this study is to construct a regional GIS <br />(geographic information system) database, at 1:24,000 scale, delineating all <br />irrigated fields and open water surfaces within the Upper Colorado River <br />Basin~ The acreage figures and crop type information can then be used to <br />derive more accurate consumptive water use estimates. In developing the <br />methodology for this project, efforts were made to gather and incorporate <br />previous work, such as existing maps and aerial photography. Cooperative <br />. ventures have been established to effectively utilize state-level initiatives <br />and knowledge of field personnel. Satellite image processing'techniques <br />are being employed to provide field inventory information for areas where <br />ancillary data are limited. <br /> <br />Thedeyelopm.ent of.this regi9nal GIS database involves three primary <br />phases: 1) vector database development, 2) satellite image processing, and <br />3) in'tegratiOhcofthevector and raster d{lta. to produce acreages and crop <br />typeinf()rmation. These'three phases will be discussed in: this report. <br /> <br />VECTOR DATABASE DEVELOPMENT <br /> <br />\ <br /> <br />Reclamation has been implementing GIS and Remote Sensing <br />technologies to facilitate' development of the Consumptive Uses and Losses <br />Report. Due to land use differences between the Upper and Lower Coloradi:): <br />River Basins, thes.e technologies have been applied differently in the two <br />regions.' . . <br /> <br /> <br />Analysis of Landsat TM (Thematic Mapper) imagery from the (LC) <br />Lower Colorado River Region states is relatively straightforward. To <br />differentiate irrigated crop land from the surrounding desert is not a <br />difficult tas}<. For this reason, the LC office began using remote sensing <br />.technology with only minimal use of GIS. The resolution of the TM imagery <br />(25 meter pixels) coupled With the l"()llfidingertOl"sinherent ina raster <br />environment, produced inaccurate acreage estimates. In order to overcome <br />this problem, LC has used SPOT panchromatic imagery (10 meter pixels) to <br />. .'tJ1~ .~ld':l:>o qat.es. The field boupgaries are being digitized <br />.... .......'... ....... ........)~~~$ -':ff i11l'agery,~i'-iba~~~:~ Tn~ pd1l.U1nT dtfff61lty <br /> <br />~4~'1~r~~:,~#ftll'.2>r.l;~,~~:~.,~e;::ii~~e~jj~; . <br />region require multFdate imagery toaccu.rately.deterinine crop types <br />throughout an entire year. ' <br /> <br /> <br />In the (UC) Upper Colorado River Region, the primary problem is <br /> <br />1 <br />