Map Layer Notes

We distinguish two types of map layers in the REDI system. The first type, the thematic layers, are the main data layers for the map. Only one thematic layer can be active at any time.

The second type is the reference layer. These are layers that help orient the viewer geographically. All, none, or any combination of them may be active at any given time.

Because of their inherent detail and complexity, some map layers will not display until a scale threshold is gained. The traffic volume reference layer, for example, would display as a useless jumble of number boxes if viewed at a regional scale. So even though a REDI user may have the traffic volume checkbox on, the layer won't actually display until the map is zoomed to 1" = 10,000' (look in the lower left corner of the map panel for current map scale). When layers are "out of scale" in this manner, they are shown in red on the map panel. In the discussion of each layer below, we specify zoom thresholds if one exists for the layer.

Thematic layers

There are three main map themes in the REDI application: public land ownership, existing land use, and planned land use. The employment lands thematic layer, which shows the status of land designated for industrial development, will be included in a future release of REDI. When no thematic layer is desired, perhaps to isolate one or more reference layers, the “None” option may be selected.

  Existing Land Use. Land use information was collected for use in the 2030 Regional Growth Forecast to distribute projected growth for the San Diego region to suitable subareas in the region. Color infra-red satellite images, black and white digital orthophotography, the SanGIS landbase, the County Assessor’s Master Property Records file, and other ancillary information were used to identify land use types. The land use information was reviewed by each of the local jurisdictions and the County of San Diego to ensure its accuracy. Land use information falls into eight categories:
  • Residential
  • Commercial
  • Industrial
  • Parks and recreation
  • Public land
  • Agriculture
  • Water
  • Not in use
Source: Color Infrared satellite imagery, black and white digital orthophoto quads, SanGIS landbase (registration) and miscellaneous sources.
Date: January 2007.
  Planned Land Use. This layer was updated from information first collected in 1990 and reflects the current land use designations of each local jurisdiction’s General Plan, and the City and County of San Diego Community Plans. Planned land use information is portrayed in eight categories:
  • Residential
  • Commercial
  • Industrial
  • Parks and recreation
  • Public land
  • Agriculture
  • Water
  • Indian reservations
Source: Local City and County General and Community Plan Land Use Elements.
Date: Summer 2005.
  Public Land Ownership. This layer excludes privately held land. Numerous public agencies were contacted to obtain information on their land holdings. These include, but are not limited to Cleveland National Forest, State Parks, BLM, California Department of Fish and Game, U.S. Fish and Wildlife Service, San Diego Unified Port District, San Diego County Office of Education, and local special districts. The SanGIS landbase, and the County Assessor’s Master Property Records File was also used as source for identifying public lands in the San Diego region. In addition, the land ownership information was reviewed by each of the local jurisdictions and the County of San Diego to ensure its accuracy. Users should be aware that this data may be too generalized for some local planning projects. There are four types of publicly-owned lands:
  • Local
  • State
  • Federal
  • Military
Source: County Assessor’s Master Property Records file, Cleveland National Forest, Bureau of Land Management (BLM), State Parks, other public agency contacts, SanGIS landbase (registration) and local agency review.
Date: January 2007.
 

Reference layers

In addition to the main thematic layers, you may find it useful to add one or more reference layers to your maps. Check any appropriate boxes to select as many reference layers as you like. Some reference layers, because of their complexity and detail, will not appear on your map until a scale threshold is reached. Where applicable, we discuss scale threshold information in the reference layer list below.


  Airports. All commercial, military, and general aviation airport runways.
Source: SANDAG.
Date: current.
  Cities. Boundaries of the 18 incorporated cities in San Diego County.
Source: SanGIS.
Date: January 2007.
  Community Plan Areas. Both the City of San Diego and the County of San Diego maintain Community Plan Areas for local planning efforts. There are two reference layers, City CPA and County CPA, used to display both jurisdictions' plan areas.
Source: County of SD Dept of Public Works Mapping Section, City of SD Community and Economic Development Dept/SanGIS.
Date: 2000.
  Elevation. The USGS 7.5 minute contour data were created by San Diego State University using procedures and standards provided by the USGS. The contour lines were scanned. This raster data was then edited, vectorized, and attribute tagged. This regional coverage is not ‘clipped’ to the regional boundary, but contains information in quad areas that go outside the San Diego region. The individual 7.5 minute quad data was only ‘visually’ edgematched before merging to create a regional coverage (therefore you will see over/under shoots along the 7.5 minute quad boundaries when zooming in to very large scales). There are two reference layers used to show elevation at a 40’or 200' contour interval.

The Elevation Contours 200 layer only appears at scales larger than 1"=20,000’.

The Elevation Contours 40 layer only appears at scales larger than 1"=4,000’.
Source: San Diego State University, USGS.
Date: Varies.
  Flood plains. 100 year and 500 year floodways and floodplains. FEMA data supplemented by County of San Diego floodplain maps to fill in areas not covered by FEMA.
Source: Federal Emergency Management Agency, SanGIS, County of San Diego.
Date: 1993, 1973 (County).
  Parcels. These data are processed by SanGIS, who receives periodic updates from the County Assessor’s office. We will update the information on a regular basis, This layer only appears at scales larger than 1"=24,000’.
Source: SanGIS, County Assessor.
Date: April 2008.
  Photo. The digital ortho photo base is made possible by a partnership of San Diego area agencies. Pixel resolution is two feet. Photo compression was performed by the Management and Information Services division of the City of Chula Vista using LizardTech's compression and storage software, MrSID. This layer only appears at scales larger than 1"=6,000’.
Source: SANDAG.
Date: Summer 2000.
  Railroads. Light-rail transit, commuter rail, and selected freight rail lines.
Source: Digital Ortho-Photos.
Date: 2008.
  Re-use. Lands designated for redevelopment or infill. These lands could potentially serve as employment land in the region.
Source: SANDAG
Date: January 2005.
  Roads. Existing major-roads and freeways maintained in SANDAG’s regional transportation database. The detailed road layer is maintained by SanGIS.
Source: SanGIS centerline road file; General Plan circulation elements of the local jurisdictions in the San Diego region; Caltrans State highway inventory (FUNC coverage); SANDAG Regional Transportation Improvement Program and Regional Transportation Plan.
Date: January 2008.
 

Terrain. Ten meter terrain grids were generated from the 1:24,000 scale USGS 7.5 minute quad elevation contour lines (at 20’ and 40’ contour intervals). Hillshading applied by SANDAG. Lighting source is from the northwest.

Source: San Diego State University, Dept. of Geography; SANDAG.
Date: Mid 1970s.
  Traffic volume. Data in this layer represent average weekday traffic volumes on significant roadways in the region. All number are given in thousands. This layer only appears at scales larger than 1"=10,000’.
Source: Caltrans, SANDAG member agencies.
Date: 2004.
  Transit. Transit routes for the region’s two transit operators are shown in this layer. The route information is categorized by local, express, and rail service. This layer only appears at scales larger than 1”=250,000’.
Source: SANDAG.
Date: March 2007.
  Tribal Lands. This layer shows the 18 reservations.
Source: SANDAG.
Date: 2004.
  Water features. Significant streams, lakes, and lagoons.
Source: SanGIS LandBase, 1994/1995 Panchromatic Digital OrthoPhoto Quarter Quads.
Date: 2006.
  Watersheds. Watersheds correspond to the hydrologic units of the hydrologic basins coverage created by Tierra Data Systems for the California Department of Forestry under specifications provided by the California Department of Water Resources.
Source: California Department of Forestry.
Date: 1999.