This existing vegetation tile is a recently completed CALVEG (Classification and Assessment with LANDSAT of Visible Ecological Groupings) map product at a scale primarily of 1:100,000 within CALVEG Zone 5 (Central Valley). The CALVEG classification system was used for vegetation typing and crosswalked to other classification systems in this database. Mapping standards meet requirements of the USDA Forest Service as defined by the FS GIS data dictionary, FGDC Vegetation standards and the FS Existing Vegetation Classification and Mapping Technical Guide. Regional add-ons are retained for crosswalking to the California Wildlife Habitat Relationship System.
For more information refer to the GIS layer description, Existing Vegetation Mid Level Map by the USDA Forest Service, Pacific Southwest Region, at http://www.fs.fed.us/r5/rsl/projects/frdb/layers/ev_mid.html.
For example - EvegTile06A_03_04_24k_v2:
<06A>_03_04_24k_v2 - Tile number (see tile index called Calveg Tiles_Ecoregions at http://www.fs.fed.us/r5/rsl/clearinghouse/gis-download.shtml)
06A_<03_04> - source year(s) of data i.e. 2002, 2003
06A_03_04_<24k> - map scale standard i.e. 1:24,000 (or <100k> for 1:100,000)
06A_04_24k_<v2>- version number
3/11/2010 (cclark, GD)
Minor overlaps corrected
PROJECT NAME: Geobook - Central Valley
PROJECT DATE: 1/2009 - 7/2009
PHASE 1 -
(tlindemann, hgordon, rjwarbington)
Data was obtained from multiple sources, at various map and temporal scales, for areas outside US Forest Service lands and crosswalked to the CALVEG classification system. One source (Suisun Marsh) was especially detailed and displayed a one-to-many relationship with CALVEG in which the most appropriate Regional Dominance Type was chosen for this project. Other sources had greater generality than that of CALVEG, such as Land Cover geospatial databases.
For each source featureclass, a frequency was run on pertinent fields in order to determine the number of unique combinations that occurred. RSL staff reviewed, edited and cross-walked each agency's vegetation dataset into the CALVEG classification system. The following fields of the standard Existing Vegetation template were populated via customized cross-walks:
For areas where no data was found (holes), multi-resolution segmentation was applied to 10-m Spot imagery to achieve delineations of vegetation polygons. These features were then photo-interpreted using the 2005 NAIP imagery.
For forested only lands (non-urban and non-agricultural) that were identified, NLCD Continuous Tree Cover was integrated using mean percentage in order to update structure values. Low estimates of tree cover values were used to identify shrubs and the higher percentages were used to populate TOTAL_TREE_CFA (cover from above), HDW_CFA and CON_CFA. A size classification raster was created and regionalized by majority to populate the OS_TREE_DIAM1. Photo interpretation with NAIP imagery was used to fill in areas with missing structural attributes or where errors were highly probable.
For the non-forested lands, the USDA Cropland layer was integrated. Photo interpreted data was not overwritten. Cross-walks were created to refine the USGS_ANDERSON2, REGIONAL_DOMINANCE_TYPE 1 & 2, COVERTYPE and WHRTYPE of the non-forested lands.
The forested and non-forested areas were integrated and topology errors corrected.
The feature class was subset into CALVEG tiles, populating ECOREGION DOMAIN, DIVISION, SECTION, SUBSECTION, TILE and CALVEGZONE fields in the process.
WHRLIFEFORM was populated based on a WHRTYPE crosswalk values. WHRSIZE was populated using another crosswalk from OS_TREE_DIAM1.
PROD (productivity) field was crosswalked based on the CALVEG_FOREST_TYPE_XWALK table, linking to REGIONAL_DOMINANCE_TYPE_1.
The final phase incorporated waterbodies (lakes, rivers, reservoirs) where missing and the coding was changed on existing polygons from "Water (General)" to more detailed coding. Where water polygons were missing or spatially inaccurate based on photo interpretation, NHD (National Hydrography Dataset) polygons were "burned" in and coded to CALVEG standards. Polygons over 2 1/2 acres not brought over from NHD and still coded as "Water (General)" were photo interpreted and coded. Remaining polygons under 2 1/2 acres (MMU) were eliminated.
DATA SOURCES (see Sourcecoverage field):
Land cover 1993 and change in land cover 2000 of the Central Valley, CA [ESRI geodatabase]. 2003. Sacramento, CA: U.S. Bureau of Reclamation, Mid Pacific Region, U.S. Fish and Wildlife Service. [April 2009]
Sacramento River Riparian Vegetation [ESRI geodatabase]. 1998. Chico, CA: CA State University, Geospatial Information Center. [April 2009]
Delta Vegetation and Land Use. 2005. [ESRI geodatabase] Sacramento, CA: CA Dept of Forestry & Fire Protection. [April 2009]
Suisun Marsh vegetation in June 2006 and change since June 2003 [ESRI geodatabase]. Sacramento, CA: CA Dept of Fish and Game. [April 2009]
National Agriculture Imagery Program (NAIP), Compressed county mosaic aerial photography. 2005 [LizardTech Mr Sid]. Salt Lake City, UT: USDA Farm Service Agency [April 2009]
Existing Vegetation. 1998-2002. [ESRI geodatabase] McClellan, CA: USDA Forest Service, Remote Sensing Lab [April 2009]
California Cropland Data Layer (CDL). [ESRI raster]. 2007. Portland, OR: USDA National Agricultural Statistics Service [April 2009]
National Hydrography Dataset (NHD) [ESRI geodatabase]. 2009. Reston, VA: U.S. Geological Survey (USGS). Available FTP: http://nhd.usgs.gov/index.html [March 2009]
Structure attributing -
National Land Cover Database (NLCD) [ESRI geodatabase]. 2001. Sioux Falls, SD: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center. Available FTP: http://www.mrlc.gov/nlcd_multizone_map.php [November 2008]