This dataset entails the delineation of impervious surfaces and artificial land cover types extracted from aerial imagery captured in early 2021. Utilization within the City of Austin The dataset plays a pivotal role in several municipal functions, encompassing the computation of the Drainage Charge managed by the Watershed Protection Department, wildfire assessments, emergency operations planning, transportation asset monitoring, urban forest management, and more. Data Updates New aerial imagery and impervious cover data are acquired by the city every two years, resulting in distinct datasets for each capture. As of its initial capture in early 2021, there have been no subsequent updates to this dataset. Downloading Instructions Some users have reported issues downloading the data. Due to the large size of the dataset, downloading can take longer than expected. We recommend following these instructions to download the data.,

This dataset entails the delineation of impervious surfaces and artificial land cover types extracted from aerial imagery captured in early 2019. Utilization within the City of Austin The dataset plays a pivotal role in several municipal functions, encompassing the computation of the Drainage Charge managed by the Watershed Protection Department, wildfire assessments, emergency operations planning, transportation asset monitoring, urban forest management, and more. Data Updates New aerial imagery and impervious cover data are acquired by the city every two years, resulting in distinct datasets for each capture. As of its initial capture in early 2019, there have been no subsequent updates to this dataset. Downloading Instructions Some users have reported issues downloading the data. Due to the large size of the dataset, downloading can take longer than expected. We recommend following these instructions to download the data.,

Impervious surfaces were derived from two existing mapping products, producing six classes of impervious area: Buildings, Roads, Railways, Roads and Railways, Airports and Aerodromes, Stormwater Infrastructure. Impervious Surfaces associated with buildings were derived from the Geoscape® Buildings Theme, which provides polygon representations of every building in Australia with a roof area equal to or greater than 9m2. Building polygons from the Greater Sydney Region were extracted and used to create the ‘Buildings’ feature. Impervious Surfaces not associated with buildings were derived from the NSW Land Use Map 2017 (inclusive of the draft Land Use Mapping for the Sydney Metropolitan Region), which provides land use mapping for NSW at a 1:10,000 reliability scale, based on the Australian Land Use and Management Classification Code. This layer was used to generate the Roads, Railways, Roads and Railways (polygons reclassified during QC) Airports and Aerodromes, and Stormwater Infrastructure features. Once both sets of features had been generated, they were intersected with LGA to aid in computation and provide additional map utility. Following this, any overlap between the Buildings features and the Land Use features was corrected using the Erase Function, before the layers were combined using the union function, and dissolved by LGA and feature class to provide LGA-level breakdowns of the prevalence and providence of impervious areas.

This 30-meter resolution data set represents the imperviousness layer for the conterminous United States for the 2001 time period. The data have been arranged into four tiles to facilitate timely display and manipulation within a Geographic Information System, browse graphic: nlcd01-partition. The National Land Cover Data Set for 2001 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of Federal agencies (www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), and the USDA Natural Resources Conservation Service (NRCS). One of the primary goals of the project is to generate a current, consistent, seamless, and accurate National Land Cover Database (NLCD) circa 2001 for the United States at medium spatial resolution. For a detailed definition and discussion on MRLC and the NLCD 2001 products, refer to Homer and others (2004) and http://www.mrlc.gov/mrlc2k.asp.. The NLCD 2001 was created by partitioning the United States into mapping-zones. A total of 68 mapping-zones browse graphic: nlcd01-mappingzones.jpg were delineated within the conterminous United States based on ecoregion and geographical characteristics, edge-matching features, and the size requirement of Landsat mosaics. Mapping-zones encompass the whole or parts of several states. Questions about the NLCD mapping zones can be directed to the NLCD 2001 Land Cover Mapping Team at the USGS/EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov.