This data set is a mosaic made from aerial photographs acquired from the Modoc National Forest with photo dates throughout the summer of 1946. The 126 original photographs were scanned and orthorectified in December 2002. The aerial photographs were scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, using PCI Ortho software in December 2002. The mosaic was created in September 2004. Additional mosaic reformatting was done in 2005 and 2020 by the California Department of Fish and Wildlife.

The Geographical Information Center (GIC) at California State University, Chico, completed a vegetation map of the Proposed Tehachapi Pass High-Speed Rail Corridor (HSRC), covering 199,493 acres. The project was funded by the Strategic Growth Council to support routing and mitigation planning for the high-speed rail system. The map was produced using heads-up digitizing based on 2012 National Agricultural Imagery Program (NAIP) imagery. The minimum mapping unit (MMU) is one acre for most vegetation types, with a smaller MMU for wetlands. Although the primary purpose of the map is to document vegetation communities, it provides additional structural data such as herbaceous, shrub, and tree cover, and information about the level of disturbance within the vegetation stand. The overall accuracy of the map exceeded the state standard of 80 percent.

This is a layer of aerial photos acquired from the Modoc National Forest with photo dates throughout the summer of 1994, scanned and orthorectified by the Geographical Information Center, California State Univ., Chico, with later processing by the California Department of Fish and Wildlife.It documents the location of aspen stands. It also provides the visual background for the display of polygons and the visual comparison of similar and more recent data sets. This is one of five data sets for a study investigating change in the size of aspen stands since 1946. Other available data sets are a 1946 aerial photo mosiac, interpreted polygons of individual aspen stands from 1946 and 1994, and a sample of aspen stand characteristics in 98 stands from 2002. Geographic extent of the imagery: The study area is the Warner Mountains south of State Highway 299.

CSU Chicos Geographical Information Center (GIC), with assistance from CDFWs Vegetation Classification and Mapping Program (VegCAMP) created a fine-scale vegetation and land use map of portions of the Modoc Plateau in California. The map follows the National Vegetation Mapping Classification standards as well A Manual of California Vegetation and covers the eco-region subsections Devils Garden and Adin Mountains. This map covers approximately 855,998 acres in Lassen and Modoc Counties. It was produced using a base of true-color 2018 one-meter National Agricultural Imagery Program (NAIP) imagery. Polygons were assessed for vegetation types, percent covers, clearing disturbance, invasive plant cover and other attributes. Overall fuzzy map accuracy was 81.6%, but individual vegetation types varied in their accuracy. Please see the mapping report and the contingency tables for details to determine confidence in individual types.For detailed information please refer to the following reports: Boul, R., T. Keeler-Wolf, J. Ratchford, T. Haynes, D. Hickson, R. Yacoub, B. Harbert, J. Evens. 2021. Classification of the Vegetation of Modoc and Lassen Counties, California. Vegetation Classification and Mapping Program, California Department of Fish and Wildlife, Sacramento, CA ; https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=183030Kreb, Brian and Geographical Information Center, California State University, Chico. Mapping Standards, Field Data Collection, and Accuracy Assessment for Vegetation Mapping in Modoc and Lassen Counties, California. Califoria Department of Fish and Wildlife; 2/1/2021. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=189051

This line feature class represents levee centerlines for 93 Levee Maintenance Agencies/Reclamation Districts in the Sacramento-San Joaquin Delta. The centerline features contain levee geometry classification that indicates whether a levee segment meets the FEMA’s Hazard Mitigation Plan (HMP) or USACE’s Public Law 84-99 (PL8499) Delta levee standards. There are four categories used in the classification of the centerlines: HMP, Below HMP, Minimally Below HMP, and PL84-99. The classification and other data associated with these centerlines were produced as results of the Levee Geometry Assessment analysis performed by the California Department of Water Resources Delta Levees and Environmental Engineering Branch in 2012. The centerlines used in this analysis are part of the dataset produced from the Delta Levee Anatomy Mapping Project in 2011 through a contract between DWR and the Geographic Information Center at California State University, Chico.