2000 Land Use by Minor Civil Division 9-County DVRPC Region	No. 78 March 2004

The Delaware Valley Regional Planning Commission (DVRPC) is an interstate, inter-county and intercity agency that provides comprehensive and coordinated planning for the orderly growth of the Delaware Valley region. As the region's metropolitan planning organization (MPO), the Commission provides technical assistance and services to its member state, county and local governments, the private sector and the public. Delaware Valley Data is our periodic series of free data bulletins and complementary analytical reports.

Methodology
This data bulletin contains 2000 land use information for the 9-County DVRPC region. The 2000 land use file is based on digital orthophotography created from aerial surveillance done in the Spring of 2000. Orthophotography combines the image characteristics of an aerial photograph with the geometric qualities of a map. Unlike a traditional aerial photograph, distortions due to the camera lens, aircraft altitude, and changes in relief (hills, stream valleys, and buildings, for example) are corrected, permitting direct measurement of distances, areas, and angles. All ground features are shown in their actual positions, and detailed portions of ground features that are typically omitted or generalized on traditional maps are evident, allowing more accurate interpretation.

Land uses were classified into thirty-one separate categories. All annotation and digitizing was done on-screen ("heads up") using ESRI ArcGIS 8 software at the 1:2400 (1 inch = 200 feet) scale. In addition to the seventeen categories utilized in DVRPC's 1995 and revised 1990 land use files, the Commission's 2000 land use file delineates parking areas associated with each of 13 land use categories and creates a separate category for agricultural bogs, located primarily in southern Burlington County.

The thirty-one 2000 land use categories are listed below, and defined in Appendix A:

Changing land uses have in some cases made it difficult to accurately interpret aerial photographs. The re-use of older buildings for purposes different than the original use, for example, can make it difficult to accurately identify the current use. The advent of flex space has likewise made it more difficult to differentiate between commercial/office spaces and industrial warehouses. These distinctions are often best made based on local knowledge and experience. DVRPC therefore asked its member county planning departments to review the draft land use files for specific errors, and the Commission's land use file was revised accordingly.

Historical Background: DVRPC's Earlier Land Use Files
Land use information and analysis is a fundamental tool in the planning process. Since 1970, the Delaware Valley Regional Planning Commission has produced land use files for the nine-county Delaware Valley region, based on information derived from aerial photography. Originally updated every 10 years, DVRPC's land use data is now updated based on aerial surveillance flown every 5 years.

DVRPC produced an extensive land use data file and regional land use map in the early 1970's. That effort was based on the Department of Housing and Urban Development/Bureau of Public Records (HUD/BPR) classification system. The 1970 land use file included 88 separate land use categories (later modified to a total of 98 categories), which were then grouped into 12 major categories. The data was tabulated by census block (over 66,000 aerial units), and the resulting file contained over 1 million separate entries. The data was then mapped at a scale of 1 inch = 1 mile, necessitating the generalization of the original data into units that were appropriate for mapping.

In the early 1980's, the 1970 land use file was updated in a very limited way by aggregating data to 14 major categories and updating only the development changes on parcels of 25 acres or more. While this interim product provided a crude data base and map, it was subsequently noted that up to a third of all development changes over the decade were on small parcels not captured by the large parcel limit. For the purposes of this bulletin, historical comparisons have therefore been made between 1970, 1990, and 2000.

The acquisition of a Computer Assisted Mapping (CAM) and Geographic Information System (GIS) in the early 1990's has significantly altered the production of land use data. In 1991, DVRPC completed a digital land use file based on aerial photography flown in April and November of 1990. Land use was interpreted in 14 separate categories from 1,330 aerials at a scale of 1 inch = 400 feet. The annotated photographs were digitized to create CAM line work which was registered to USGS 1 inch = 2,000 feet quad maps. Each area was annotated with its land use classification and the results incorporated into the DVRPC CAM/GIS system.

In 1998, DVRPC completed and released land use information based on the interpretation of aerial photographs taken in the Spring of 1995. Land use was interpreted in 17 separate categories from 1,330 photo atlas sheets at a scale of 1 inch = 400 feet, and again digitized to create CAM line work registered to USGS 1 inch = 2,000 feet quad maps. Also in 1998, the 1990 land use files were revised, after a review of the original files identified some inconsistencies in the detail for parking and some other small parcels. It was also decided at that time that it would be useful to attach parking to its related land use, to allow an alternative method of data organization and make the 1990 file consistent with the categories used in the 1995 land use file.

Because of these changes in the way land uses were classified, data in this bulletin should not be compared to any DVRPC land use data issued prior to Data Bulletin #58: 1990 Revised Land Use by Minor Civil Division (August 1998). Additionally, the use of digital orthophotography as opposed to traditional aerial photography has allowed more accurate land use interpretation, particularly when differentiating between various developed uses. Any comparisons with earlier land use data, particularly between developed land use categories and/or within specific municipalities, should therefore be done with caution.

2000 Land Use Highlights and Trends
Tables 1 and 2 summarize county and regional land use data, and Appendices B and C provide municipal-level land use data (in square miles and acres, respectively). To allow comparison with DVRPC's earlier land use files, the numbers have been aggregated using the same general methodology and categories as were used previously. Areas of single-family detached units, row homes, and mobile homes, for example, have been aggregated as "single-family residential". All identified parking lots (regardless of their related use) have been included in the transportation category, and light and heavy industrial uses have been combined as "manufacturing". As in previous DVRPC land use files, 25% of the residential land in every county except Philadelphia was subtracted from the residential land area and added to transportation, to account for local roads. In Philadelphia, 25% was subtracted from all classifications except military, mining, and water, and added to transportation, to account for the increased density of the local road network.

Table 3 describes changes in residential areas and other developed categories (including manufacturing, transportation, utility, commercial, community service, military, mining, and recreation uses) between 1970 and 2000, and Table 4 summarizes changes in agricultural areas and in other undeveloped land areas, including wooded and vacant land areas and water. For comparison purposes, the land areas delineated as "agricultural bogs" in 2000 were re-allocated to other uses based on the classification of the same areas in 1995. GIS-based analysis determined that 72% of the bog area was categorized as agricultural in 1995; 14% was categorized as wooded; 13% was categorized as water; and a small percentage (less than 1% overall) was categorized as either single-family residential or vacant. Beginning in 2005, agricultural bogs will be analyzed as a separate category.

Highlights of the 2000 land use data file include the following:

• Of the region's total land area in 2000, 19% was in residential use; 19% was in other developed uses; 22% was in agricultural use; an additional 38% was either vacant or wooded; and 2% was covered by water. By comparison, in 1990, 17% of the region's land area was residential; 14% was in other developed uses; 2% was covered by water; and 67% was in agricultural use or otherwise undeveloped.
• Residential land area increased by 13% (over 52,000 acres) between 1990 and 2000, despite the fact that the region's population increased by only 4%. Approximately one-quarter acre was developed with residential uses for every resident that the region gained during the decade. Other developed uses consumed an additional 65,000 acres, for a net increase of over 117,000 acres in developed land .
• Development over the most recent decade has continued at a faster rate than seen during the previous two decades, when developed acreage increased by an average of just over 83,000 acres per decade. From 1970 to 1990, development occurred at a rate of approximately one acre per hour. Since 1990, the rate of development has accelerated to one acre every 45 minutes.
• Chester, Bucks, and Montgomery counties had the highest net increase in residential acres between 1990 and 2000. In terms of percentage increase, Chester, Bucks, and Gloucester counties each experienced a 20% or greater increase in residential acreage.
• The region lost over 90,000 acres of agricultural land area between 1990 and 2000, and other undeveloped areas declined by an additional 26,000 acres, for a total loss of over 117,000 undeveloped acres. Bucks, Chester, and Montgomery counties realized the greatest net losses of agricultural land during the decade, and Chester and Montgomery counties also saw the greatest declines in other undeveloped acres.
• Transportation areas (which include highways, streets and parking lots as well as rail, air and marine uses) occupied over 230,000 acres and accounted for 9.5% of the region's total land area in 2000, having increased by 22% since 1990. This increase may be due at least in part to an improved ability to identify individual parking lots.
• As expected, the region's acres in manufacturing and mining uses declined slightly, while military acres remained about the same. With over 57,000 acres, recreational uses increased by almost 27% and accounted for 2% of the region's total land area in 2000. Again, while significant, this increase may at least in part be due to more accurate land use interpretation.

The land use tables in this Data Bulletin may be downloaded from the DVRPC website (www.dvrpc.org). Additional analysis as well as 2000 land use maps can be found in DVRPC's Analytical Data Report #12: Land Use in the Delaware Valley, 1970 through 2000 (April 2004), available by contacting DVRPC. Digital GIS files of 2000 or previous land use data may also be ordered through DVRPC. Contact mapsales@dvrpc.org for more information.

Appendix A - Land Use Categories [.pdf 18 KB]
Appendix B - 2000 Land Use (square miles) [.pdf 40KB | .xls 412 KB] - Right Click to Download
Appendix C - 2000 Land Use (acres) [.pdf 59KB | .xls 251 KB] - Right Click to Download

Data bulletin #78 is one of a series of bulletins designed to disseminate information to member state, county and local governments and other interested parties. For more information on Data Bulletins and Analytical Data Reports, please visit the Delaware Valley Regional Planning Commission's website (www.dvrpc.org) or contact DVRPC at the telephone number below.

The Delaware Valley Regional Planning Commission was established in 1965 by interstate compact between Pennsylvania and New Jersey to plan for the orderly growth and development of the region, and to provide a variety of planning and technical assistance services responding to regional issues. DVRPC maintains a significant database for twenty-eight counties encompassing New Jersey, Delaware, Pennsylvania and Maryland. Included in the database are data profiles at the regional, county and municipal level and for other census geography as requested. DVRPC produces a diverse range of services, including demographic and economic data and projections; mapping and aerial photography; computer assisted mapping; geographic information systems; impact studies; and policy and program development.

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