This layer was developed by the Fire Department to use in our annual reporting to the state. We must report total incidents by Urban,Suburban, and Rural. Using the State of California formula for urban,suburban was found to be not applicable to Los Angeles County. The [...]]]> Download the shapefile  here: Urban Suburban Rural (zipped shapefile).

This layer was developed by the Fire Department to use in our annual reporting to the state. We must report total incidents by Urban,Suburban, and Rural. Using the State of California formula for urban,suburban was found to be not applicable to Los Angeles County. The state was using census tract to compute the USR and only using population. This worked for them as they had to look at the whole state by county. We used the following variables:

1. Total Population

2. Employment

3 Street miles

4. Housing

We then re-distributed the totals down to a one-mile grid. Then a scoring system for each variable was developed. One  being a low, and ten 10 being the highest. We then totaled up the scores for each category. What we found was that we needed to ‘smooth’  the results to ensure a smooth transition from urban,suburban, and rural. We found that using ESRI’s Neighborhood model was a perfect tool to finalize our results. We documented our methodology and asked the Urban Research Division of Los Angeles County to independently analyze our results. With some minor tweaking the USR layer was approved and is now used for all our reporting.

NHGIS Site

The National Historical Geographic Information System (NHGIS) website recently is an incredibly valuable tool for historic demographics information. You just need to register.

From their site:

The National Historical Geographic Information System (NHGIS) provides, free of charge, aggregate census data and GIS-compatible boundary files for the United States between [...]]]>

NHGIS Site

The National Historical Geographic Information System (NHGIS) website recently is an incredibly valuable tool for historic demographics information.  You just need to register.

From their site:

The National Historical Geographic Information System (NHGIS) provides, free of charge, aggregate census data and GIS-compatible boundary files for the United States between 1790 and 2000. NHGIS offers the following options to obtain data:

The Census Bureau (http://www.census.gov/) maintains geographic boundaries for the analysis and mapping of demographic information across the United States. Every 10 years the Census Bureau counts the population of the United States as mandated by Constitution. The Census Bureau releases the results of this county as demographic data with [...]]]> Census Geography Background

The Census Bureau (http://www.census.gov/) maintains geographic boundaries for the analysis and mapping of demographic information across the United States. Every 10 years the Census Bureau counts the population of the United States as mandated by Constitution. The Census Bureau releases the results of this county as demographic data with geographic identifiers so that maps and analysis can be performed on the US population.

For a quick introduction to Census geography, click the thumbnail on the right which shows the relationship between Census Blocks, Block Groups, Tracts, and Counties.

For detailed information about the Census Geography, here are some other links:

• Geographic Shapefile Concepts Overview
• TIGER/Line Shapefile home page
• TIGER/Line Shapefile technical documentation

LA County Samples

Countywide	CSU LA
Census Blocks 2010	Zoomed at CSULA

What is unique about LA County’s data?

1. It is clipped to the ocean boundary. Raw Census data includes a 3 mile buffer into the ocean, which impacts cartography.
2. Each census blocks are assigned with the community name based on the 2011 redistricting unit community names.
3. IMPORTANT! It has been updated to re-include Census Tract 1370.00, which the Census Bureau mistakenly merged with tract 8002.04. Note – until the Census Bureau releases updated population files this update will impact population mapping since population tables will not have 13700.00 (it’s population will be part of 8002.04 showing higher numbers than reality). Please see this post on the County Enterprise GIS about this. We have included the raw file for those who want to use it.

Maps showing what changed

General Area	Zoomed in

How was this data created?

This data was downloaded from Census Bureau website: ftp://ftp2.census.gov/geo/pvs/tiger2010st/06_California/06037/ and clipped to the County Boundary using ESRI’s ArcGIS Desktop. A new field “COMMNAME” was added and populated with city and community names based on 2011 redistricting unit community names in the census block data. This dataset has unique identifier field “GEOID10” for each record, and the census tract and census block number combined field “CTCB10”, block group field “BG10” and census block number field “CB10”.

Download/Access the data

• 2010 Census Blocks.lyr (ArcGIS 10 layer file)- for LA County staff with access to the GIS Repository
• LA County updated Block File – cb2010.shp (zipped shapefile)
• 2010 Census Blocks (zipped original tiger shapefile) – CB2010_Tiger - this is the original file before the changes to Tracts 8002.04 and 1370.00

The Census Bureau (http://www.census.gov/) maintains geographic boundaries for the analysis and mapping of demographic information across the United States. Every 10 years the Census Bureau counts the population of the United States as mandated by Constitution. The Census Bureau releases the results of this county as demographic data with geographic [...]]]> Census Geography Background

The Census Bureau (http://www.census.gov/) maintains geographic boundaries for the analysis and mapping of demographic information across the United States.  Every 10 years the Census Bureau counts the population of the United States as mandated by Constitution.  The Census Bureau releases the results of this county as demographic data with geographic identifiers so that maps and analysis can be performed on the US population.

For a quick introduction to Census geography, click the thumbnail on the right which shows the relationship between Census Blocks, Block Groups, Tracts, and Counties.

For detailed information about the Census Geography, here are some other links:

• Geographic Shapefile Concepts Overview
• TIGER/Line Shapefile home page
• TIGER/Line Shapefile technical documentation

LA County Samples

Countywide	Downtown
Census Tracts 2010	Zoomed at Downtown LA

What is unique about LA County’s data?

1. It  is clipped to the ocean boundary.  Raw Census data includes a 3 mile buffer into the ocean, which impacts cartography.
2. IMPORTANT! It has been updated to re-include Census Tract 1370.00, which the Census Bureau mistakenly merged with tract 8002.04.  Note – until the Census Bureau releases updated population files this update will impact population mapping since population tables will not have 13700.00 (it’s population will be part of 8002.04 showing higher numbers than reality). Please see this post on the County Enterprise GIS about this.  We have included the raw file for those who want to use it.

Maps showing what changed

General Area	Zoomed in

How was this data created?

This data was downloaded from Census Bureau website: http://www.census.gov/cgi-bin/geo/shapefiles2010/file-download and clipped to the County Boundary using  ESRI’s ArcGIS Desktop.  Two new fields were added in census tract data – area in square feet and area in square miles. This dataset has unique identifier field “GEOID10” for each record and the census tract number fields “CT10” and “LABEL” (6-digit number and 6-digit number with decimal point, respectively).

Download/Access the data

• 2010 Census Tracts.lyr (ArcMap 10 Layer File) – for LA County staff with access to the GIS Repository
  
• LA County updated Tract File – ct2010.shp (zipped shapefile)
• Original 2010 Census Tract File – ct2010_original.shp (zipped shapefile) – this is the original file before the changes to Tract 8002.04 and 1370.00

Statistical Areas 2000

The Statistical Areas dataset contains Statistical Areas from the LA County Department of Regional Planning (DRP). Statistical Areas are communities that can be grouped together to show areas of geographical connection in the county. To do this use the STAT_D field. Similar areas have the same first few [...]]]>

Statistical Areas 2000

The Statistical Areas dataset contains Statistical Areas from the LA County Department of Regional Planning (DRP). Statistical Areas are communities that can be grouped together to show areas of geographical connection in the county. To do this use the STAT_D field. Similar areas have the same first few digits. The more similar the number, the closer together the geographic areas are.

Data is designed to be accurate to the Thomas Brothers datasets for mapping purposes. It does not correspond to Census Bureau data. You must have a license for the Thomas Brothers data to use this dataset.  THIS DATASET IS BEING PHASED OUT; will be removed from portal very soon.

Data can be downloaded here:

• Download zipped shapefile

Here’s the link to their download page:  We do not have this data; but since we get a lot of requests for census tracts or other census data for our County, it seems logical to have a link here.  This data is available from the US Census Bureau.  2010 data is not yet available.

Here’s the link to their download page:  http://www.census.gov/geo/www/cob/bdy_files.html or click here.