This map page grid was designed and implemented by the Los Angeles County Fire Department, Information Management Division, and Geographic Information Systems Section. Wholly based on the United States National Grid (USNG), it aims to be the Los Angeles County regional grid because of its ease of use and extensive coverage.

Each block measures 2,000 meters by 2,000 meters and are comprised of four 1,000 meter/1 kilometer USNG blocks. i.e. 11SLT4771, 11SLT4871, 11SLT4770 and 11SLT4870; left to right and up to down. For ease of use each 2,000 meter block is designated by a page number from 1 to 9,750, and it is inferred that the 1,000 meter divisions of each page are designated A, B, C or D; left to right and up to down. Therefore, each 1,000 meter block within this regional grid has a unique descriptor of 4 numerals and 1 letter.

The region covered by the grid includes Los Angeles County completely and 2 of the islands in the Channel Islands archipelago that fall into the Los Angeles County jurisdiction. It also covers close to 100% of Orange County, 50% of Ventura County, and the Los Angeles County adjacent portions of Kern County, San Bernardino County and Riverside County, and a portion of Marine Corps Base Camp Pendleton in Northwest San Diego County.

PAGE = Grid Number

Reference Date: 2016

Contact Information:

Los Angeles County Fire Department Geographic Information Systems Section LACoFDGIS@fire.lacounty.gov

ALERT stands for Automated Local Evaluation in Real Time, a method of using remote sensors to transmit data to a central computer in real time. This standard was developed in the 1970s by the National Weather Service and has been used by organizations of all levels such as the National Weather Service, Army Corps of Engineers and Bureau of Reclamation.Orange County initiated its ALERT System in 1983 to provide additional quantitative weather information to support storm operations personnel. Sensors were initially installed along the Santa Ana River and in four South County Channels: San Juan Creek, Arroyo Trabuco Creek, Oso Creek, and Aliso Creek. The system has subsequently been expanded to monitor other flood control channels and retarding basins.The Orange County ALERT System consists of three computer base stations and three radio repeaters. The radio repeater located on Santiago Peak receives and re-transmits telemetry from field sensors located in Los Angeles, San Bernardino, and Orange Counties. One of the two receiver base stations located at the OC Public Works yard on Glassell Street in Orange is a server connected to the OC Public Works Department Intranet, providing access to Department personnel from their workstations. In response to extreme weather conditions the OC Public Works - Department Operations Center (DOC) opens to coordinate monitoring and response to threats of flooding, mudslides, and debris flows. During these periods, the ALERT System provides crucial continuous information to the DOC.

Land boundaries for Orange County, cities, and unincorporated areas (based on the five supervisorial districts). Contains additional geodemographic data on population and housing from the US Census 2021 American Community Survey (ACS).

California State Lands Commission Offshore Oil Leases in the vicinity of Santa Barbara, Ventura, and Orange County.The polygons in this layer show the position of Offshore Oil Leases as documented by former State Lands Senior Boundary Determination Officer, Cris N. Perez and as reviewed and updated by GIS and Boundary staff.Background: This layer represents active offshore oil and gas agreements in California waters, which are what remain of the more than 60 originally issued. These leases were issued prior to the catastrophic 1969 oil spill from Platform A in federal waters off Santa Barbara County, and some predate the formation of the Commission. Between 2010 and 2014, the bulk of the approximately $300 million generated annually for the state's General Fund from oil and gas agreements was from these offshore leases.In 1921, the Legislature created the first tidelands oil and gas leasing program. Between 1921 and 1929, approximately 100 permits and leases were issued and over 850 wells were drilled in Santa Barbara and Ventura Counties. In 1929, the Legislature prohibited any new leases or permits. In 1933, however, the prohibition was partially lifted in response to an alleged theft of tidelands oil in Huntington Beach. It wasn't until 1938, and again in 1955, that the Legislature would allow new offshore oil and gas leasing. Except for limited circumstances, the Legislature has consistently placed limits on the areas that the Commission may offer for lease and in 1994, placed the entirety of California's coast off-limits to new oil and gas leases. Layer Creation Process:In 1997 Cris N. Perez, Senior Boundary Determination Officer of the Southern California Section of the State Lands Division, prepared a report on the Commission’s Offshore Oil Leases to:A. Show the position of Offshore Oil Leases. B. Produce a hard copy of 1927 NAD Coordinates for each lease. C. Discuss any problems evident after plotting the leases.Below are some of the details Cris included in the report:I have plotted the leases that were supplied to me by the Long Beach Office and computed 1927 NAD California Coordinates for each one. Where the Mean High Tide Line (MHTL) was called for and not described in the deed, I have plotted the California State Lands Commission CB Map Coordinates, from the actual field surveys of the Mean High Water Line and referenced them wherever used. Where the MHTL was called for and not described in the deed and no California State Lands Coordinates were available, I digitized the maps entitled, “Map of the Offshore Ownership Boundary of the State of California Drawn pursuant to the Supplemental Decree of the U.S. Supreme Court in the U.S. V. California, 382 U.S. 448 (1966), Scale 1:10000 Sheets 1-161.” The shore line depicted on these maps is the Mean Lower Low Water (MLLW) Line as shown on the Hydrographic or Topographic Sheets for the coastline. If a better fit is needed, a field survey to position this line will need to be done.The coordinates listed in Cris’ report were retrieved through Optical Character Recognition (OCR) and used to produce GIS polygons using Esri ArcGIS software. Coordinates were checked after the OCR process when producing the polygons in ArcMap to ensure accuracy. Original Coordinate systems (NAD 1927 California State Plane Zones 5 and 6) were used initially, with each zone being reprojected to NAD 83 Teale Albers Meters and merged after the review process.While Cris’ expertise and documentation were relied upon to produce this GIS Layer, certain polygons were reviewed further for any potential updates since Cris’ document and for any unusual geometry. Boundary Determination Officers addressed these issues and plotted leases currently listed as active, but not originally in Cris’ report. On December 24, 2014, the SLA boundary offshore of California was fixed (permanently immobilized) by a decree issued by the U.S. Supreme Court United States v. California, 135 S. Ct. 563 (2014). Offshore leases were clipped so as not to exceed the limits of this fixed boundary. Lease Notes:PRC 1482The “lease area” for this lease is based on the Compensatory Royalty Agreement dated 1-21-1955 as found on the CSLC Insider. The document spells out the distinction between “leased lands” and “state lands”. The leased lands are between two private companies and the agreement only makes a claim to the State’s interest as those lands as identified and surveyed per the map Tract 893, Bk 27 Pg 24. The map shows the State’s interest as being confined to the meanders of three sloughs, one of which is severed from the bay (Anaheim) by a Tideland sale. It should be noted that the actual sovereign tide and or submerged lands for this area is all those historic tide and submerged lands minus and valid tide land sales patents. The three parcels identified were also compared to what the Orange County GIS land records system has for their parcels. Shapefiles were downloaded from that site as well as two centerline monuments for 2 roads covered by the Tract 893. It corresponded well, so their GIS linework was held and clipped or extended to make a parcel.MJF Boundary Determination Officer 12/19/16PRC 3455The “lease area” for this lease is based on the Tract No. 2 Agreement, Long Beach Unit, Wilmington Oil Field, CA dated 4/01/1965 and found on the CSLC insider (also recorded March 12, 1965 in Book M 1799, Page 801).Unit Operating Agreement, Long Beach Unit recorded March 12, 1965 in Book M 1799 page 599.“City’s Portion of the Offshore Area” shall mean the undeveloped portion of the Long Beach tidelands as defined in Section 1(f) of Chapter 138, and includes Tract No. 1”“State’s Portion of the Offshore Area” shall mean that portion of the Alamitos Beach Park Lands, as defined in Chapter 138, included within the Unit Area and includes Tract No. 2.”“Alamitos Beach Park Lands” means those tidelands and submerged lands, whether filled or unfilled, described in that certain Judgment After Remittitur in The People of the State of California v. City of Long Beach, Case No. 683824 in the Superior Court of the State of California for the County of Los Angeles, dated May 8, 1962, and entered on May 15, 1962 in Judgment Book 4481, at Page 76, of the Official Records of the above entitled court”*The description for Tract 2 has an EXCEPTING (statement) “therefrom that portion lying Southerly of the Southerly line of the Boundary of Subsidence Area, as shown on Long Beach Harbor Department {LBHD} Drawing No. D-98. This map could not be found in records nor via a PRA request to the LBHD directly. Some maps were located that show the extents of subsidence in this area being approximately 700 feet waterward of the MHTL as determined by SCC 683824. Although the “EXCEPTING” statement appears to exclude most of what would seem like the offshore area (out to 3 nautical miles from the MHTL which is different than the actual CA offshore boundary measured from MLLW) the 1964, ch 138 grant (pg25) seems to reference the lands lying seaward of that MHTL and ”westerly of the easterly boundary of the undeveloped portion of the Long Beach tidelands, the latter of which is the same boundary (NW) of tract 2. This appears to then indicate that the “EXCEPTING” area is not part of the Lands Granted to City of Long Beach and appears to indicate that this portion might be then the “State’s Portion of the Offshore Area” as referenced in the Grant and the Unit Operating Agreement. Section “f” in the CSLC insider document (pg 9) defines the Contract Lands: means Tract No. 2 as described in Exhibit “A” to the Unit Agreement, and as shown on Exhibit “B” to the Unit Agreement, together with all other lands within the State’s Portion of the Offshore Area.Linework has been plotted in accordance with the methods used to produce this layer, with record lines rotated to those as listed in the descriptions. The main boundaries being the MHTL(north/northeast) that appears to be fixed for most of the area (projected to the city boundary on the east/southeast); 3 nautical miles from said MHTL on the south/southwest; and the prolongation of the NWly line of Block 50 of Alamitos Bay Tract.MJF Boundary Determination Officer 12-27-16PRC 4736The “lease area” for this lease is based on the Oil and Gas Lease and Agreement as found on the CSLC insider and recorded August 17, 1973 in BK 10855 PG 432 Official Records, Orange County. The State’s Mineral Interests are confined to Parcels “B-1” and “B-2” and are referred to as “State Mineral Lands” comprising 70.00 Acres. The lessee each has a right to certain uses including but not limited to usage of utility corridors, 110 foot radius parcels surrounding well-sites and roads. The State also has access to those same roads per this agreement/lease. Those uses are allowed in what are termed “State Lands”-Parcel E and “Leased Lands” which are defined as the “South Bolsa Lease Area”-Parcel C (2 parcels) and “North Bolsa Lease Area”-Parcel D. The “State Lands”-Parcel E are actually 3 parcels, 2 of which are within road right-of-ways. MJF Boundary Determination Officer 12-28-16

This data set maps the soil-slip susceptibility for several areas in southwestern California. Created using Environmental Systems Research Institute's ARC/INFO software, the data base consists of raster maps containing grid cells coded with soil- slip susceptibility values. In addition, the data set includes the following graphic and text products: (1) postscript graphic plot files containing the soil-slip susceptibility map, topography, cultural data, and a key of the colored map units, and (2) PDF and text files of the Readme (including the metadata file as an appendix) and accompanying text, and a PDF file of the plot files. Intense winter rains commonly generated debris flows in upland areas of southwestern California. These debris flows initiate as small landslides referred to as soil slips. Most of the soil slips mobilize into debris flows that travel down slope at varying speeds and distances. The debris flows can be a serious hazard to people and structures in their paths. The soil-slip susceptibility maps identify those natural slopes most likely to be the sites of soil slips during periods of intense winter rainfall. The maps were largely derived by extrapolation of debris-flow inventory data collected from selected areas of southwestern California. Based on spatial analyses of soil slips, three factors in addition to rainfall, were found to be most important in the origin of soil slips. These factors are geology, slope, and aspect. Geology, by far the most important factor, was derived from existing geologic maps. Slope and aspect data were obtained from 10-meter digital elevation models (DEM). Soil-slip susceptibility maps at a scale of 1:24,000 were derived from combining numerical values for geology, slope, and aspect on a 10-meter cell size for 128 7.5' quadrangles and assembled on 1:100,000-scale topographic maps. The resultant maps of relative soil-slip susceptibility represent the best estimate generated from available debris-flow inventory maps and DEM data.

Power Outages by County

A dataset listing California counties by population for 2024.

description: CDF, USDA Forest Service Region 5, BLM, NPS, Contract Counties and other agencies jointly maintain a comprehensive fire perimeter GIS layer for public and private lands throughout the state. The data covers fires back to 1950 and fires 10 acres and greater. Depictions of the historical fire perimeters Ventura, Los Angeles, San Bernardino, Orange, Riverside, and San Diego counties were pulled together from downloadable information on the CAL FIRE (California Department of Forestry and Fire Protection) web site (http://frap.cdf.ca.gov/data/frapgisdata/select.asp). This information shows the fire history for these six counties prior to the recent (late October 2007) fires. Please read the attached metadata carefully to further undersand the information presented here. The Data Viewer used in BIOS has a query function (see tool bar across the top of the map screen) to query all fields including date fields to narrow the number of fire perimeters shown to the period of time you are interested in.; abstract: CDF, USDA Forest Service Region 5, BLM, NPS, Contract Counties and other agencies jointly maintain a comprehensive fire perimeter GIS layer for public and private lands throughout the state. The data covers fires back to 1950 and fires 10 acres and greater. Depictions of the historical fire perimeters Ventura, Los Angeles, San Bernardino, Orange, Riverside, and San Diego counties were pulled together from downloadable information on the CAL FIRE (California Department of Forestry and Fire Protection) web site (http://frap.cdf.ca.gov/data/frapgisdata/select.asp). This information shows the fire history for these six counties prior to the recent (late October 2007) fires. Please read the attached metadata carefully to further undersand the information presented here. The Data Viewer used in BIOS has a query function (see tool bar across the top of the map screen) to query all fields including date fields to narrow the number of fire perimeters shown to the period of time you are interested in.

Facilities Web Map. SCAQMD Facilities in Orange County and the urban portions of Los Angeles, Riverside and San Bernardino counties.

OC Hydstra Flood Station Data Feed DescriptionThis feature layer contains the cumulative data (multiple temporal observations per station) processed by Orange County's Hydstra Flood Monitoring ALERT System Station Data Feed on latest rainfall amounts and rates for every 15-minutes interval.The following list provides the temporal levels of rainfall data reporting summary:Hourly Levels:Current Hourly Rainfall Intensity (inches)1-Hour Rainfall (inches)3-Hours Rainfall (inches)6-Hours Rainfall (inches)12-Hours Rainfall (inches)Daily Levels:1-Day Rainfall (inches)2-Day Rainfall (inches)3-Day Rainfall (inches)Historical SummaryALERT stands for Automated Local Evaluation in Real Time, a method of using remote sensors to transmit data to a central computer in real time. This standard was developed in the 1970s by the National Weather Service and has been used by organizations of all levels such as the National Weather Service, Army Corps of Engineers and Bureau of Reclamation.Orange County initiated its ALERT System in 1983 to provide additional quantitative weather information to support storm operations personnel. Sensors were initially installed along the Santa Ana River and in four South County Channels: San Juan Creek, Arroyo Trabuco Creek, Oso Creek, and Aliso Creek. The system has subsequently been expanded to monitor other flood control channels and retarding basins.The Orange County ALERT System consists of three computer base stations and three radio repeaters. The radio repeater located on Santiago Peak receives and re-transmits telemetry from field sensors located in Los Angeles, San Bernardino, and Orange Counties. One of the two receiver base stations located at the OC Public Works yard on Glassell Street in Orange is a server connected to the OC Public Works Department Intranet, providing access to Department personnel from their workstations. In response to extreme weather conditions the OC Public Works - Department Operations Center (DOC) opens to coordinate monitoring and response to threats of flooding, mudslides, and debris flows. During these periods, the ALERT System provides crucial continuous information to the DOC.

This dataset includes one file for each of the 51 counties that were collected, as well as a CA_Merged file with the parcels merged into a single file.Note – this data does not include attributes beyond the parcel ID number (PARNO) – that will be provided when available, most likely by the state of California.DownloadA 1.6 GB zipped file geodatabase is available for download - click here.DescriptionA geodatabase with parcel boundaries for 51 (out of 58) counties in the State of California. The original target was to collect data for the close of the 2013 fiscal year. As the collection progressed, it became clear that holding to that time standard was not practical. Out of expediency, the date requirement was relaxed, and the currently available dataset was collected for a majority of the counties. Most of these were distributed with minimal metadata.The table “ParcelInfo” includes the data that the data came into our possession, and our best estimate of the last time the parcel dataset was updated by the original source. Data sets listed as “Downloaded from” were downloaded from a publicly accessible web or FTP site from the county. Other data sets were provided directly to us by the county, though many of them may also be available for direct download. Â These data have been reprojected to California Albers NAD84, but have not been checked for topology, or aligned to county boundaries in any way. Tulare County’s dataset arrived with an undefined projection and was identified as being California State Plane NAD83 (US Feet) and was assigned by ICE as that projection prior to reprojection. Kings County’s dataset was delivered as individual shapefiles for each of the 50 assessor’s books maintained at the county. These were merged to a single feature class prior to importing to the database.The attribute tables were standardized and truncated to include only a PARNO (APN). The format of these fields has been left identical to the original dataset. The Data Interoperablity Extension ETL tool used in this process is included in the zip file. Where provided by the original data sources, metadata for the original data has been maintained. Please note that the attribute table structure changes were made at ICE, UC Davis, not at the original data sources.Parcel Source InformationCountyDateCollecDateCurrenNotesAlameda4/8/20142/13/2014Download from Alamenda CountyAlpine4/22/20141/26/2012Alpine County PlanningAmador5/21/20145/14/2014Amador County Transportation CommissionButte2/24/20141/6/2014Butte County Association of GovernmentsCalaveras5/13/2014Download from Calaveras County, exact date unknown, labelled 2013Contra Costa4/4/20144/4/2014Contra Costa Assessor’s OfficeDel Norte5/13/20145/8/2014Download from Del Norte CountyEl Dorado4/4/20144/3/2014El Dorado County AssessorFresno4/4/20144/4/2014Fresno County AssessorGlenn4/4/201410/13/2013Glenn County Public WorksHumboldt6/3/20144/25/2014Humbodt County AssessorImperial8/4/20147/18/2014Imperial County AssessorKern3/26/20143/16/2014Kern County AssessorKings4/21/20144/14/2014Kings CountyLake7/15/20147/19/2013Lake CountyLassen7/24/20147/24/2014Lassen CountyLos Angeles10/22/201410/9/2014Los Angeles CountyMadera7/28/2014Madera County, Date Current unclear likely 7/2014Marin5/13/20145/1/2014Marin County AssessorMendocino4/21/20143/27/2014Mendocino CountyMerced7/15/20141/16/2014Merced CountyMono4/7/20144/7/2014Mono CountyMonterey5/13/201410/31/2013Download from Monterey CountyNapa4/22/20144/22/2014Napa CountyNevada10/29/201410/26/2014Download from Nevada CountyOrange3/18/20143/18/2014Download from Orange CountyPlacer7/2/20147/2/2014Placer CountyRiverside3/17/20141/6/2014Download from Riverside CountySacramento4/2/20143/12/2014Sacramento CountySan Benito5/12/20144/30/2014San Benito CountySan Bernardino2/12/20142/12/2014Download from San Bernardino CountySan Diego4/18/20144/18/2014San Diego CountySan Francisco5/23/20145/23/2014Download from San Francisco CountySan Joaquin10/13/20147/1/2013San Joaquin County Fiscal year close dataSan Mateo2/12/20142/12/2014San Mateo CountySanta Barbara4/22/20149/17/2013Santa Barbara CountySanta Clara9/5/20143/24/2014Santa Clara County, Required a PRA requestSanta Cruz2/13/201411/13/2014Download from Santa Cruz CountyShasta4/23/20141/6/2014Download from Shasta CountySierra7/15/20141/20/2014Sierra CountySolano4/24/2014Download from Solano Couty, Boundaries appear to be from 2013Sonoma5/19/20144/3/2014Download from Sonoma CountyStanislaus4/23/20141/22/2014Download from Stanislaus CountySutter11/5/201410/14/2014Download from Sutter CountyTehama1/16/201512/9/2014Tehama CountyTrinity12/8/20141/20/2010Download from Trinity County, Note age of data 2010Tulare7/1/20146/24/2014Tulare CountyTuolumne5/13/201410/9/2013Download from Tuolumne CountyVentura11/4/20146/18/2014Download from Ventura CountyYolo11/4/20149/10/2014Download from Yolo CountyYuba11/12/201412/17/2013Download from Yuba County