Laserfiche WebLink
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 90.2 -Determine Field Polygon <br />Boundaries <br />Date: 9 February 2004 <br />1. Introduction <br />This memorandum summarizes the first draft delivery of the irrigated parcel mapping prepared under <br />Task 90 -- Image Base Map and Irrigated Field Boundaries, Subtask 90.2 -Determine Field Polygon <br />Boundaries. These activities are described in RTi's Scope of Work for SPDSS Phase 1 and 2 Spatial <br />System Integration Component. Per the Scope of Work, (page 4) the objective of Task 90 includes the <br />following: <br />Delineate field boundaries for all irrigated parcels. <br />Also described in the Scope of Work (page 5) is the approach for this Subtask that includes: <br />The Contractor will digitize field boundaries on the DOQQ and IRS satellite image base maps <br />using as a reference the multispectral Landsat imagery described in Task 89.2. <br />With this memo, irrigated field parcels are being delivered as a first draft and, for Districts 1, 2, 3, and 64, <br />will be delivered in final format by November 30, 2004. Irrigated parcels for the remaining districts will <br />be delivered in final format at the end of Phase 3 of SPDSS. Editing and revision of these draft products <br />will be conducted under Subtasks 91.3 and 91.4. <br />2. Approach <br />Irrigated field parcels for the 2001 irrigation season were developed from interpretation of Landsat <br />imagery, an orthophoto image base map, and irrigated parcel data from NCWCD and CSU. The CSU <br />data were coverages of irrigation center pivots and the NCWCD data were interpretations of irrigated <br />lands in 1997. Both of these data sources used satellite imagery as their basis for interpretation. These <br />parcel data were used as a reference in our mapping along with the orthophotos, Landsat imagery from <br />2001, and other information. <br />The 2001 multi-date Landsat imagery were combined into a composite Normalized Difference Vegetation <br />Index (NDVI) as described in the memo for Subtask 89.1 -Finalize Methods and Order Imagery. The <br />image base map was derived from high-resolution digital orthophotographs as described in the draft <br />memo for Subtask 90.1 -Image Base Map. <br />As shown in Figure 1, the approach to mapping irrigated parcels involved five steps: printing maps; <br />interpreting maps and drawing boundaries; quality assurance and quality control (QAQC) of field <br />boundary drawings; digitizing boundaries; and, QAQC of the digitized field boundaries. <br />Page 1 of 6 ~l~lverslde Technology, lnc. <br />Gr:HS•: Rx:soarcc~s En;:ncer~nc.~~ad cuns.nrmc <br />