This map is designated as Final.

Land-Use Data Quality Control

Every published digital survey is designated as either ‘Final’, or ‘Provisional’, depending upon its status in a peer review process.

Final surveys are peer reviewed with extensive quality control methods to confirm that field attributes reflect the most detailed and specific land-use classification available, following the standard DWR Land Use Legendspecific to the survey year. Data sets are considered ‘final’ following the reconciliation of peer review comments and confirmation by the originating Regional Office. During final review, individual polygons are evaluated using a combination of aerial photointerpretation, satellite image multi-spectral data and time series analysis, comparison with other sources of land use data, and general knowledge of land use patterns at the local level.

Provisional datasets have been reviewed for conformance with DWR’s published data record format, and for general agreement with other sources of land use trends. Comments based on peer review findings may not be reconciled, and no significant edits or changes are made to the original survey data.

The 2006 Kern County land use survey data was developed by the State of California, Department of Water Resources (DWR) through its Division of Planning and Local Assistance (DPLA). Digitized land use boundaries and associated attributes were gathered by staff from DWR’s San Joaquin District (SJD), using extensive field visits and aerial photography. Land use polygons in agricultural areas were mapped in greater detail than areas of urban or native vegetation. Prior to the summer field survey by SJD, DPLA staff analyzed Landsat 5 imagery to identify fields likely to have winter crops. The combined land use data went through standard quality control procedures before final processing. Quality control procedures were performed jointly by staff at DWR’s DPLA Land Use Unit and SJD. This data was developed to aid DWR’s ongoing efforts to monitor land use for the main purpose of determining current and projected water uses. The associated data are considered DWR enterprise GIS data, which meet all appropriate requirements of the DWR Spatial Data Standards, specifically the DWR Spatial Data Standards version 2.1, dated March 9, 2016. DWR makes no warranties or guarantees - either expressed or implied - as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. Comments, problems, improvements, updates, or suggestions should be forwarded to gis@water.ca.gov. This data represents a land use survey of Kern County conducted by DWR, SJD staff, under the leadership of David Scruggs, Senior Land and Water Use Supervisor. The field work for this survey was conducted during the summer of 2006. SJD staff physically visited each delineated field, noting the crops grown at each location. Field survey boundary data was developed using: 1. The county was surveyed with a combination of 2005 one meter and 2006 two meter NAIP imagery. 2. The 2005 images were used in the spring of 2006 to develop the land use field boundary lines that would be used for the summer survey. The 2006 imagery was used for identification in the field and to edit any boundary line changes from the 2005 imagery. 3. These images and land use boundaries were copied onto laptop computers that were used as the field collection tools. The staff took these laptops in the field and virtually all areas were visited to positively identify the land use. The site visits occurred from June through September 2006 (approx.). Land use codes were digitized directly into the laptop computers using AUTOCAD (and a standardized digitizing process) any land use boundaries changes were noted and corrected back in the office. 4. After quality control/assurance procedures were completed on each file (DWG), the data was finalized for the summer survey. The primary focus of this land use survey is mapping agricultural fields. Urban residences and other urban areas were delineated using aerial photo interpretation. Some urban areas may have been missed, especially in forested areas. Rural residential land use was delineated by drawing polygons to surround houses and other buildings along with some of the surrounding land. These footprint areas do not represent the entire footprint of urban land. Sources of irrigation water were identified for general areas and occasionally supplemented by information obtained from landowners. Water source information was not collected for each field in the survey, so the water source listed for a specific agricultural field may not be accurate. Before final processing, standard quality control procedures were performed jointly by staff at DWR's SJD, and at DSIWM headquarters under the leadership of Jean Woods, Senior Land and Water Use Supervisor. After quality control procedures were completed, the data was finalized. The positional accuracy of the digital line work, which is based upon the orthorectified NAIP imagery, is approximately 6 meters. The land use attribute accuracy for agricultural fields is high, because almost every delineated field was visited by a surveyor. The accuracy is 95 percent because some errors may have occurred. Possible sources of attribute errors are: a) Human error in the identification of crop types, b) Data entry errors.