HEADWATERS ECONOMICS GEOGRAPHIC DATA LIBRARY DOCUMENTATION TITLE: Dataset Name: CNTY_Sprawl2000 Dataset Type: ACCESS GENERAL DESCRIPTION: This dataset describes the percent of private, developable land within each county that is developed at different housing densities (ex. percent of area developed at exurban densities) in 2000. DATA SOURCE(S): US Census Bureau Headwaters Economics Date of Original Source Data: 2006 DATASET EXTENT: Western US TABLES CODES AND VALUES: ITEM ITEM DESCRIPTION FIPS 5 digit NAME County Name DEV_AC # of developable acres -excluding water, pub. land, slope > 30 TOT_POP 2000 Population from Census TOT_HU Sum of housing units from original block shp files POP_DEN TOT_POP / DEV_AC URB_AC Sum the area of blocks w/ 0-1 ac lots URB_HU Sum the number of housing units in blocks w/ 0-1 ac lots URB_POP Sum the pop in blocks w/ 0-1 ac lots URB_PCT (URB_AC / DEV_AC)*100 SUBURB_AC Sum the area of blocks w/ 1-10 ac lots SUBURB_HU Sum the number of housing units in blocks w/ 1-10 ac lots SUBURB_POP Sum the pop in blocks w/ 1-10 ac lots SUBURB_PCT (SUBURB_AC / DEV_AC)*100 EXURB_AC Sum the area of blocks w/ 10-40 ac lots EXURB_HU Sum the number of housing units in blocks w/ 10-40 ac lots EXURB_POP Sum the pop in blocks w/ 10-40 ac lots EXURB_PCT (EXURB_AC / DEV_AC)*100 DATA LINEAGE SUMMARY: We collected data from Census TIGER/LINE and Blocks database (SF1) to measured 2 factors: 1. Per capita land consumption (area of residential development / population), where the area of residential development is calculated as the acreage of developable land within census blocks per county with lot sizes smaller than 40 acres (this includes exurban, suburban, & urban densities). This area calculation excludes public land, water, and slope > 30 degrees. 2. Percent exurban (total acreage of census blocks with lot sizes between 10 and 40 acres / total acreage of developable land within the county). Below are the data processing steps: 1. Compile census block data for western 12 states. -go to http://arcdata.esri.com/data/tiger2000/tiger_download.cfm -select the state -> select by layer (not county) -> select & download "Census Blocks Demographics (SF1)" ---this is the tabular data that we'll link to the GIS data -select & download "Census Blocks 2000" (grab as many counties at once as you can ---the max is 20 MB & most counties are around 1 MB, so you should be able to do each state in a few downloads). -select & download "Census Blocks 1990" (same process as w/ 2000 data) ---we may end up using the 1990 data to calculate change in sprawl over time, but this will require that we get the SF1 census tables for 1990 which isn’t available online. -merge all the counties w/in each state so you end up w/: or_blk.shp, wa_blk.shp, id_blk.shp, mt_blk.shp, ak_blk.shp, etc. 2. Add the population & housing attributes from the SF1 table to the GIS layers: (P007001) pop2000 population 2000 (H001001) hse_units housing units 3. Erase public lands, water, & slope > 30 degrees from the block layers. Use 90m dems to exclude slope > 30 degrees. Call these layers: or_blk-priv.shp, wa_blk-priv.shp, id_blk-priv.shp, mt_blk-priv.shp, ak_blk-priv.shp, etc. 4. Calculate the average lot size per block. Name this field LS (lot size), where LS = hse_units / # of developable acres in the block. Note: the # of developable acres is just the total acreage of the block after excluding the federal lands, water, & slope > 30 degrees (so the acreage of the blk-priv polys). 5. Calculate the area of residential development per county. Sum (per county) the area of blk-priv polys where LS < 40 acres (Call this RD –residential development acres). 6. Calculate the per capita land consumption per county. Divide RD by each counties total population (Call this PCLC –per capita land consumption). Note: calculate the total population as the sum of pop2000 for all blocks w/in each county. 7. Calculate the percent of each county that is developed at exurban densities. EXURB = (the total acreage of blk-priv polys where LS >= 10 acres and LS < 40 acres) / (the total acreage blk-priv polys) DATA SOURCES CONTACT(S): Name: Department of Commerce, Census Bureau, Geography Division Abbr.name: USCB Address: 8903 Presidential Parkway, Room 520 WP I Upper Marlboro, MD 20772 Phone: (301) 763-1128 Email: tiger@census.gov Fax: NA Contact Person: Geography Department Web site: http://www.census.gov/geo/www/tiger HEADWATERS ECONOMICS CONTACT: Name: Headwaters Economics Geographic Data Library Abbr. Name: HEGDL Address: Headwaters Economics 566 Highland St. Helena, Montana 59601 Web site: http://www.headwaterseconomics.org Contact Person: Patty Gude Phone: (406)599-7425 Email: patty@headwaterseconomics.org