Under contract to the Natural Communities Coalition (NCC), Aerial Information Systems (AIS) created an updated fine-scale vegetation map of portions of Orange County originally mapped in 2012-2015. AIS conducted field reconnaissance for this project in June 2023, and field verification in May 2024. California Native Plant Society (CNPS) under a separate contract with NCC was tasked to conduct the Accuracy Assessment.
The mapping study area, consists of approximately 86,000 acres of open space and adjacent urban and agricultural lands, including habitat located in both the Central and Coastal Subregions of Orange County. Work was performed on the project between 2022 and 2025. The primary purpose of the project was to provide a good basis for trend analyses for long-term land management and conservation within the remaining natural lands of Orange County.
CNPS under separate contract and in collaboration with CDFW VegCAMP developed the floristic vegetation classification used for the project. The floristic classification follows protocols compliant with the Federal Geographic Data Committee (FGDC) and National Vegetation Classification Standards (NVCS). The 2022 vegetation update used the same mapping classification as the 2012 project and is based on the floristic classification (AECOM, 2013), Manual of California Vegetation Second Edition (Sawyer et al., 2009), and the updated project floristic vegetation key (Buck-Diaz et al., 2025).
The updated vegetation map was produced applying heads-up digitizing techniques using a baseline 1-meter resolution natural color digital image created in 2022 by the National Agricultural Imagery Program (NAIP), in conjunction with ancillary data and imagery sources. Map polygons are assessed for Vegetation Type, Percent Cover, Exotics, Development Disturbance, and other attributes. The minimum mapping unit (MMU) is 1 acre for upland types and 0.5 acres for wetlands and other special types.
Field reconnaissance and accuracy assessment enhanced map quality. There was a total of 100 mapping classes. The overall Accuracy Assessment score for the final vegetation map,at the Alliance and Group levels, is 85 percent. More information can be found in the project report, which is bundled with the vegetation map published for BIOS here: https://filelib.wildlife.ca.gov/Public/BDB/GIS/BIOS/Public_Datasets/3200_3299/ds3214.zip
References:
AECOM. 2013. Vegetation Classification Report for Orange County. Unpublished report prepared for the Nature Reserve of Orange County. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=65188
Aerial Information Systems, Inc (AIS). 2025. Orange County Vegetation Mapping Update 2025, Final Vegetation Mapping Report. March 2025. Aerial Information Systems, Inc. Redlands, California. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=233168
Buck-Diaz, J., T. Reyes, L. Breidenthal, B. King, and J.M. Evens. 2025. Change Detection and Accuracy Assessment for the 2022 Orange County Vegetation ReMap. Report to the Natural Communities Coalition. California Native Plant Society, Vegetation Program. Sacramento, CA.
CNPS. 2025. A Manual of California Vegetation, Online Edition. http://www.cnps.org/cnps/vegetation/; California Native Plant Society, Sacramento, CA.
Federal Geographic Data Committee (FGDC). 2008. National Vegetation Classification Standard, Version 2 FGDC-STD-005-2008 (version 2). Vegetation Subcommittee, Federal Geographic Data Committee, FGDC Secretariat, U.S. Geological Survey. Reston, VA. 55 pp. and Appendices.
Sawyer, J.O., T. Keeler-Wolf, and J. Evens. 2009. A Manual of California Vegetation. California Native Plant Society, Sacramento, CA.
