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SPDSS Memorandum <br />To: Ray Alvarado, Ray Bennett <br />From: Riverside Technology, inc., Timothy Martin and Nils Babel <br />Subject: SPDSS Spatial System Integration Component, Subtask 90.1 -Obtain and Process Data <br />(Image Base Map) <br />Date: 9 February 2004 <br />1. Introduction <br />This memorandum summarizes the procedures and results of the Image Base Map prepared under Task <br />90--Image Base Map and Irrigated Field Boundaries, Subtask 90.1-Obtain and Process Data. These <br />activities are described in RTi's Scope of Work for SPDSS Phase 1 and 2 Spatial System Integration <br />Component. As described in the Scope of Work (page 4) the objective of Task 90 includes the following: <br />Develop a digital, seamless image base map for the entire South Platte and North Platte River <br />basins... . <br />The deliverable for this Subtask 90.1 is described in the Scope of Work (page 5), Deliverable 90.1. This <br />memo accompanies a set of work products including: <br />• The image base map in MrSID compressed format; <br />• An image boundary shapefile with the boundaries and sources of the various imagery used to <br />produce the base map; <br />• A the boundary shapefile showing the extent of the 23 tiles making up the seamless database; <br />• A series of 62 hardcopy maps at a scale of 1:40,000 for the entire study area. <br />The above products and this memo were initially provided to the State in draft on October 30, 2003. The <br />products have been revised as final deliverables, incorporating comments and suggestions by the State. <br />A portion of the data within the seamless orthoimage database was provided by Weld County per <br />agreement with CWCB, dated 5 March 2003. This agreement specifies that the Weld County data cannot <br />be distributed without written permission of the County. Subsequently, Weld County gave their approval <br />to distribute these data to other state agencies in an email dated 20 November 2003. To accommodate all <br />potential users, we have prepared two versions of the database. The primary version contains the Weld <br />County data and is not distributable outside of state agencies without written permission from Weld <br />County. The second database version is fully distributable and does not contain any of the Weld County <br />proprietary data. In its place, as described in further detail below, we have inserted older USGS data <br />where available and for some areas, typically outside of the irrigated regions, there is no data. <br />2. Approaches and Method <br />The black and white, digitally compressed, seamless image base map was created using USGS Digital <br />Orthophoto Quarter Quadrangles (DOQQs), orthophotography from Weld County, Indian Remote <br />Sensing satellite imagery, and Landsat panchromatic imagery. Most of the image base map is made up of <br />USGS DOQQs with a horizontal ground resolution of lm by lm. An example of these data is shown in <br />Figure 1. DOQQ imagery from the USGS was chosen for its high resolution and for its spatial accuracy, <br />which provide a superior base for mapping irrigated parcels and related characteristics. <br />In addition to the 1418 USGS DOQQs acquired for this project, CWCB shared the cost with USGS for <br />updating another 340 DOQQs. For these areas, the previously available USGS digital orthophotos from <br />Page 1 of 8 ~l~lverslde Technology, lnc. <br />4N:rfer Resources Fnyrneerrng urnd Curzsurtrnq <br />