Article Posted by Michael Byrne, Geospatial Information Officer (GIO)
The Bureau of Reclamation’s Central Valley Habitat Monitoring Program (CVHM) released its final dataset this winter. The program was initiated in 2000 and a comprehensive mapping plan for the Central Valley Project (CVP) service area was developed. This monitoring and mapping program was designed to identify changes within habitats and land cover that have occurred within CVP service area. This program operated on a 5 year cycle with new monitoring beginning in 2005.
This spatial is now posted on Cal-Atlas and available to all state and local agencies, and the private sector. This latest dataset contains land cover data for 2000 and 2005 and identifies areas of change by means of a table that codes the land cover types from the two dates. Specific change can be identified such as agricultural to grassland or can be simplified down to Agriculture to Natural, Natural to Urban and so forth. This allows the user to visually identify areas of natural habitat and agricultural gain or loss.
These data contain 33 habitat classifications based on California Wildlife Habitat Relationships (CWHR) and can be generalized down to eight basic classifications.
Updates and revisions have been made to the 2000 habitat layer since its prior release in 2004. Most of these revisions occurred around the urban fringes.
In addition to identifying land cover type with NAIP 1 meter imagery, various sources were used to develop the land cover set. These sources are as follows:
- The California Department of Conservation Farmland Mapping Program for the year 2004
- Crop information from the U.S.D.A. Farm Services Agency for 2006 where available.
- Hydrologic mapping or water boundaries from USGS National Hydrography Dataset (NHD).
- U.S. Census information for 2000
The identification of rural residential areas is an addition to the 2005 monitoring cycle. In brief, rural residential data was collected for the CVHM 2005 monitoring cycle using segmentation processes and census 2000 data by weighting the imagery and thematic layer to identify rural residential areas. Polygons within the identified areas were classed as Rural Residential.
The downloadable GIS file contains land cover features that represent habitat in 2000 and 2005, rural residential areas for 2005, habitat change table, land cover code table, raster land cover format, layer files, style sheet and metadata.
CVHM data between the years 1993 and 2000 can also be found at this site along with USFS 2000 land cover data.
This data can be found on the CalAtlas site. Go to http://atlas.ca.gov/ >> Download >> Imagery, Base Maps, Land Cover >> LandCover >> Central Valley Land Cover (at the bottom of the list)
For more detailed description please read the full metadata located on CalAtlas.