Published: August 2022A vector polygon GIS file of all city and town boundaries in New York State. The file was originally a compilation of U.S. Geological Survey 1:100,000-scale digital vector files and NYS Department of Transportation 1:24,000-scale and 1:75,000-scale digital vector files. Boundaries were revised to 1:24,000-scale positional accuracy and selectively updated based on municipal boundary reviews, court decisions and NYS Department of State Local Law filings for annexations, dissolutions, and incorporations. Currently, boundary changes are made based on NYS Department of State Local Law filings (http://locallaws.dos.ny.gov/). Additional updates and corrections are made as needed in partnership with municipalities.

Publication Date: APR 2018. A vector polygon GIS file of all village boundaries in New York State. The file was originally a compilation of U.S. Geological Survey 1:100,000-scale digital vector files and NYS Department of Transportation 1:24,000-scale and 1:75,000-scale digital vector files. Boundaries were revised to 1:24,000-scale positional accuracy and selectively updated based on municipal boundary reviews and NYS Department of State Local Law filings for annexations, dissolutions, and incorporations. Currently, boundary changes are made based on NYS Department of State Local Law filings (http://locallaws.dos.ny.gov/). Additional updates and corrections are made as needed in partnership with municipalities. Additional metadata, including field descriptions, can be found at the NYS GIS Clearinghouse: http://gis.ny.gov/gisdata/inventories/details.cfm?DSID=927.

© NYS Office of Information Technology Services GIS Program Office (GPO)

Publication Date: February 2020. Updated as needed. Current as of the Publication Date.

A vector polygon layer of all city and town boundaries in New York State. The source data was originally a compilation of U.S. Geological Survey 1:100,000-scale digital vector files and NYS Department of Transportation 1:24,000-scale and 1:75,000-scale digital vector files. Boundaries were revised to 1:24,000-scale positional accuracy and selectively updated based on municipal boundary reviews, court decisions and NYS Department of State Local Law filings for annexations, dissolutions, and incorporations. Currently, boundary changes are made based on NYS Department of State Local Law filings (http://locallaws.dos.ny.gov/). Additional updates and corrections are made as needed in partnership with municipalities.

Additional metadata, including field descriptions, can be found at the NYS GIS Clearinghouse: http://gis.ny.gov/gisdata/inventories/details.cfm?DSID=927.

Spatial Reference of Source Data: NAD 1983 UTM Zone 18N. Spatial Reference of Map Service: WGS 1984 Web Mercator Auxiliary Sphere.

This map service is available to the public.

The State of New York, acting through the New York State Office of Information Technology Services, makes no representations or warranties, express or implied, with respect to the use of or reliance on the Data provided. The User accepts the Data provided “as is” with no guarantees that it is error free, complete, accurate, current or fit for any particular purpose and assumes all risks associated with its use. The State disclaims any responsibility or legal liability to Users for damages of any kind, relating to the providing of the Data or the use of it. Users should be aware that temporal changes may have occurred since this Data was created.

Geospatial data about Onondaga County, New York Municipalities. Export to CAD, GIS, PDF, CSV and access via API.

The U.S. Geological Survey (USGS) is providing a polygon feature class containing the delineated areas of postglacial and glacial deposits within the Binghamton East quadrangle of south-central Broome County, New York, 2014-2021. Surficial units included are alluvium, alluvial fans, outwash, glacial lake clay, ice-contact deposit, and variable thicknesses of till. The shapefile was created and intended for use with geographic information system (GIS) software. A companion report, USGS Scientific Investigations Report 2021-5026 (Van Hoesen and others, 2021; https://doi.org/10.3133/sir20215026) further describes data collection and map preparation.

This Scene consists of the detailed 2014 USGS CMGP Post Sandy LiDAR Survey of New York City. along with over 1 million 3D Buildings for the city of New York available as part of the New York Cities OpenData initiative. A thematically symbolized 3D tree inventory for Roosevelt Island shows the value of LiDAR in validating tree survey heights. The LiDAR Dataset consists of data acquired and processed to assist in the evaluation of storm damage and erosion of the local environment as part of USGS Hurricane Sandy response along the Atlantic Seaboard.

The point map shows violations found during the last inspection of the food service establishments. The initial view of the map is broken up into large geographic areas and displays the number of violations in each area. To drill down to a smaller geographic area, click directly on the area of the map or click the plus sign to zoom in on the map. The map can be filtered by facility, city, and county by changing these options under the Filter tab. Last inspection data is the most recently submitted and available data.

This map excludes inspections conducted in New York City (https://nycopendata.socrata.com/), Suffolk County (http://apps.suffolkcountyny.gov/health/Restaurant/intro.html) and Erie County (http://www.healthspace.com/erieny). Inspections are a “snapshot” in time and are not always reflective of the day-to-day operations and overall condition of an establishment. This map is currently updated monthly. Occasionally, remediation may not appear until the following month due to the timing of the updates. Some counties provide this information on their own websites and information found there may be more frequently updated.

For more information check out http://www.health.ny.gov/regulations/nycrr/title_10/part_14/subpart_14-1.htm, or go to the "About" section.

The U.S. Geological Survey (USGS) is providing a polygon feature class delineating and describing the subsurface facies within the Binghamton East 1:24,000 quadrangle of south-central Broome County, New York, 2014-2021. The shapefile was created and intended for use with geographic information system (GIS) software. A companion report, USGS Scientific Investigations Report 2021-5026 (Van Hoesen and others, 2021; https://doi.org/10.3133/sir20215026) further describes data collection and map preparation.

U.S. Census Bureau QuickFacts statistics for Clarkstown town, Rockland County, New York. QuickFacts data are derived from: Population Estimates, American Community Survey, Census of Population and Housing, Current Population Survey, Small Area Health Insurance Estimates, Small Area Income and Poverty Estimates, State and County Housing Unit Estimates, County Business Patterns, Nonemployer Statistics, Economic Census, Survey of Business Owners, Building Permits.

The DOH Radon Program contracts with a radon testing laboratory to provide short-term charcoal radon test kits, radon test kit analysis and results to residents. The contract laboratory provides the radon test results to the individual home owner and the DOH Radon Program. All testing data is entered into our database. From this database, we are able to create radon prevalence maps, design special outreach activities and campaigns, and track the location in the home where the detector was placed.

The radon test results obtained from this database may not be reflective of all radon tests completed in New York State. There are approximately 30,000-40,000 radon tests completed each year in New York State that are not purchased through the NYSDOH Radon Program. These tests are completed by resident home owners, inspectors, schools, etc. across the state. A map by town is currently not available, but users can view a map by county. The county map is Radon Test Results By County: Beginning 1987 and can be accessed from the main catalog.

For more information, check out http://www.health.ny.gov/environmental/radiological/radon/radon.htm or go to the "About" tab.

Incorporated PlacesThis feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Census Bureau, displays Incorporated Places (legal entities). Per USCB, "The legal designations, powers, and functions of incorporated places vary from state to state. Incorporated places include cities, towns (except in New England, New York, and Wisconsin where the Census Bureau recognizes towns as MCDs for census purposes), boroughs (except in Alaska, where the Census Bureau recognizes boroughs as equivalents of counties, and New York, where the Census Bureau recognizes the five boroughs that constitute New York City as MCDs), villages, and other lesser known identifiers."Trenton, New JerseyData currency: This cached Esri federal service is checked weekly for updates from its enterprise federal source (Incorporated Places) and will support mapping, analysis, data exports and OGC API – Feature access.NGDAID: 88 (Series Information for Census Tract State-based TIGER/Line Shapefiles, Current)OGC API Features Link: (Incorporated Places) copy this link to embed it in OGC Compliant viewersFor more information, please visit: Series Information for Place State-based TIGER/Line Shapefiles, CurrentFor feedback please contact: Esri_US_Federal_Data@esri.comNGDA Data SetThis data set is part of the NGDA Governmental Units, and Administrative and Statistical Boundaries Theme Community. Per the Federal Geospatial Data Committee (FGDC), this theme is defined as the "boundaries that delineate geographic areas for uses such as governance and the general provision of services (e.g., states, American Indian reservations, counties, cities, towns, etc.), administration and/or for a specific purpose (e.g., congressional districts, school districts, fire districts, Alaska Native Regional Corporations, etc.), and/or provision of statistical data (census tracts, census blocks, metropolitan and micropolitan statistical areas, etc.). Boundaries for these various types of geographic areas are either defined through a documented legal description or through criteria and guidelines. Other boundaries may include international limits, those of federal land ownership, the extent of administrative regions for various federal agencies, as well as the jurisdictional offshore limits of U.S. sovereignty. Boundaries associated solely with natural resources and/or cultural entities are excluded from this theme and are included in the appropriate subject themes."For other NGDA Content: Esri Federal Datasets

The U.S. Geological Survey (USGS) is providing a compilation of geologic well records (n=221) collected from 2014-2020 within the Binghamton East 1:24,000 quadrangle in south-central Broome County, New York. The well records were obtained from: 1) previous U.S. Geological Survey groundwater investigations, 2) the U.S. Geological Survey’s National Water Information System (NWIS), 3) the New York State Department of Environmental Conservation (NYSDEC) Water Well Contractor Program, and 4) the New York State Department of Transportation (NYSDOT). The dataset is in comma-separated values (CSV) format. A companion report, USGS Scientific Investigations Report 2021-5026 (Van Hoesen and others, 2021; https://doi.org/10.3133/sir20215026) further describes data collection and map preparation.

Analysis of ‘Town Polygon’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/10ef725d-5e1b-4685-81df-1c6ff2614e2b on 27 January 2022.

--- Dataset description provided by original source is as follows ---

Connecticut Town Line includes the line features of a layer named Town. Town is a 1:24,000-scale, polygon and line feature-based layer that includes state, county and town (municipal) boundary features depicted on the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps for the State of Connecticut. This layer only includes information for Connecticut. Line features include State, county, and town (municipal) boundaries. Polygon features depict the geographic areas for individual towns (municipalities). A town may be represented by more than one polygon feature. For example, in addition to representing the portion of a town on the mainland, a polygon feature may also define an island along the coast of Long Island Sound. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984 and latitude and longitude coordinates that define the boundary between the states of Connecticut and New York in Long Island Sound. Attribute information is comprised of codes to classify and cartographically symbolize political boundaries by type and identify the geographic areas encompassed by individual towns. Polygon feature attributes include state, county, and town codes and names. Feature length and geographic area are encoded for linear and polygon features, respectively. This layer was originally published in 1994. With the exception of the Middletown-Portand town boundary, the 2005 edition, includes the same features originally published in 1994. The Middletown-Portand was corrected and changed from its location, as depicted on the USGS topographic quadrangle maps, from along the banks of the Connecticut River in Portand to the middle of the Connecticut River south of Wilcox Island to the Pecausett Meadows area in Portland. Some attribute information has been slightly modified and made easier to use.

Connecticut Town Polygon includes the polygon features of a layer named Town. Town is a 1:24,000-scale, polygon and line feature-based layer that includes state, county and town (municipal) boundary features depicted on the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps for the State of Connecticut. This layer only includes information for Connecticut. Line features include State, county, and town (municipal) boundaries. Polygon features depict the geographic areas for individual towns (municipalities). A town may be represented by more than one polygon feature. For example, in addition to representing the portion of a town on the mainland, a polygon feature may also define an island along the coast of Long Island Sound. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984 and latitude and longitude coordinates that define the boundary between the states of Connecticut and New York in Long Island Sound. Attribute information is comprised of codes to classify and cartographically symbolize political boundaries by type and identify the geographic areas encompassed by individual towns. Polygon feature attributes include state, county, and town codes and names. Feature length and geographic area are encoded for linear and polygon features, respectively. This layer was originally published in 1994. With the exception of the Middletown-Portand town boundary, the 2005 edition, includes the same features originally published in 1994. The Middletown-Portand was corrected and changed from its location, as depicted on the USGS topographic quadrangle maps, from along the banks of the Connecticut River in Portand to the middle of the Connecticut River south of Wilcox Island to the Pecausett Meadows area in Portland. Some attribute information has been slightly modified and made easier to use.

--- Original source retains full ownership of the source dataset ---

Publication Date: February 2020. Updated as needed. Current as of the Publication Date.

A vector polygon layer of all city and town boundaries in New York State. The source data was originally a compilation of U.S. Geological Survey 1:100,000-scale digital vector files and NYS Department of Transportation 1:24,000-scale and 1:75,000-scale digital vector files. Boundaries were revised to 1:24,000-scale positional accuracy and selectively updated based on municipal boundary reviews, court decisions and NYS Department of State Local Law filings for annexations, dissolutions, and incorporations. Currently, boundary changes are made based on NYS Department of State Local Law filings (http://locallaws.dos.ny.gov/). Additional updates and corrections are made as needed in partnership with municipalities.

Additional metadata, including field descriptions, can be found at the NYS GIS Clearinghouse: http://gis.ny.gov/gisdata/inventories/details.cfm?DSID=927.

Spatial Reference of Source Data: NAD 1983 UTM Zone 18N. Spatial Reference of Map Service: WGS 1984 Web Mercator Auxiliary Sphere. This map service is available to the public.

The State of New York, acting through the New York State Office of Information Technology Services, makes no representations or warranties, express or implied, with respect to the use of or reliance on the Data provided. The User accepts the Data provided “as is” with no guarantees that it is error free, complete, accurate, current or fit for any particular purpose and assumes all risks associated with its use. The State disclaims any responsibility or legal liability to Users for damages of any kind, relating to the providing of the Data or the use of it. Users should be aware that temporal changes may have occurred since this Data was created.Credit: NYS Office of Information Technology Services GIS Program Office (GPO). Primary Contact: GPO, GISBoundaries@its.ny.gov, 518-242-5029.

Please note: this data is live (updated nightly) to reflect the latest changes in the City's systems of record.Overview of the Data:The operational purpose of the tax parcel data set is to facilitate the calculation and collection of property taxes. Each publicly or privately owned property in the city of Rochester has an official tax parcel record. This feature layer shows the polygon boundaries for each of the over 65,000 tax parcels in the city, along with several fields from their parcel records that detail information about the property, including ownership, property type, and assessed values. How does the tax map system work in New York State? What does Section, Block, Lot refer to?Each county in the state has a tax map that includes all of the parcels in each of its cities, towns, and villages. The county tax map is subdivided into sections of even, modular units that are 8,000 feet by 12,000 feet. Each of these sections are then subdivided into blocks of up to 100 parcels. Blocks are typically formed by following natural boundaries (i.e., roads, rivers, railroad tracks). Lot numbers are assigned to each parcel in a block following a set pattern according to their location on the map. Each parcel is thus assigned a Section, Block, Lot (SBL) number for identification and tax administration purposes. For more information on this identification system, please see the General Guide for Tax Mapping in New York State, put out by the Property Tax Assessment Administration.Related Resources:For a searchable interactive mapping application, please visit the City of Rochester's Property Information explorer tool. For further information about the city's property tax assessments, please contact the City of Rochester Assessment Bureau. To access the City's zoning code, please click here.

This data is a collection of sanitary sewer mains within Westchester County (excluding the Westchester County Trunkline). The data was initially digitized from the early 1990's Sanitary Sewer Evaluation Study (SSIS) and then augmented with more recent and up to date data from local governments where available. As of October 5, 2015 this is the most up to date version of the sewer mains available.

© Westchester County, City of Mount Vernon, Town of Cortlandt, Village of Briarcliff Manor, Village of Buchanan, Village of Croton, Village of Irvington, Village of Larchmont, Town of Mamaroneck, Village of Mount Kisco, Town of North Castle, Village of Ossining, Village of Pleasantville, City of Rye, City of Yonkers and Town of Somers This layer is sourced from giswww.westchestergov.com.

The DOH Radon Program contracts with a radon testing laboratory to provide short-term charcoal radon test kits, radon test kit analysis and results to residents. The contract laboratory provides the radon test results to the individual home owner and the DOH Radon Program. All testing data is entered into our database. From this database, we are able to create radon prevalence maps, design special outreach activities and campaigns, and track the location in the home where the detector was placed.

The radon test results obtained from this database may not be reflective of all radon tests completed in New York State. There are approximately 30,000-40,000 radon tests completed each year in New York State that are not purchased through the NYSDOH Radon Program. These tests are completed by resident home owners, inspectors, schools, etc. across the state. A map by town is currently not available, but users can view a map by county. The county map is Radon Test Results By County: Beginning 1987 and can be accessed from the main catalog.

For more information, check out http://www.health.ny.gov/environmental/radiological/radon/radon.htm. The "About" tab contains additional details concerning this dataset.

A dataset listing New York counties by population for 2024.

AbstractUrbanization often substantially influences animal movement and gene flow. However, few studies to date have examined gene flow of the same species across multiple cities. In this study, we examine brown rats (Rattus norvegicus) to test hypotheses about the repeatability of neutral evolution across four cities: Salvador, Brazil; New Orleans, USA; Vancouver, Canada; New York City, USA. At least 150 rats were sampled from each city and genotyped for a minimum of 15,000 genome-wide SNPs. Levels of genome-wide diversity were similar across cities, but varied across neighborhoods within cities. All four populations exhibited high spatial autocorrelation at the shortest distance classes (< 500 m) due to limited dispersal. Coancestry and evolutionary clustering analyses identified genetic discontinuities within each city that coincided with a resource desert in New York City, major waterways in New Orleans, and roads in Salvador and Vancouver. Such replicated studies are crucial to assessing the generality of predictions from urban evolution, and have practical applications for pest management and public health. Future studies should include a range of global cities in different biomes, incorporate multiple species, and examine the impact of specific characteristics of the built environment and human socioeconomics on gene flow. Usage notesPLINK .map file for New Orleans rat SNP GenotypesPLINK .map file for New Orleans SNP genotypes. The genotypes themselves are in the .ped file of the same name, and the .map file contains the chromosomal coordinates for each SNP.NOL.plink.mapPLINK .ped file for New Orleans rat SNP GenotypesPLINK .ped file for New Orleans SNP genotypes. The genotypes themselves are in the .ped file, and the .map file contains the chromosomal coordinates for each SNP.NOL.plink.pedPLINK .map file for New York City rat SNP GenotypesPLINK .map file for New York City SNP genotypes. The genotypes themselves are in the .ped file of the same name, and the .map file contains the chromosomal coordinates for each SNP.NYC.plink.mapPLINK .ped file for New York City rat SNP GenotypesPLINK .ped file for New York City SNP genotypes. The genotypes themselves are in the .ped file, and the .map file contains the chromosomal coordinates for each SNP.NYC.plink.pedPLINK .map file for Salvador, Brazil rat SNP GenotypesPLINK .map file for Salvador, Brazil SNP genotypes. The genotypes themselves are in the .ped file of the same name, and the .map file contains the chromosomal coordinates for each SNP.SAL.plink.mapPLINK .ped file for Salvador, Brazil rat SNP GenotypesPLINK .ped file for Salvador, Brazil SNP genotypes. The genotypes themselves are in the .ped file, and the .map file contains the chromosomal coordinates for each SNP.SAL.plink.pedPLINK .map file for Vancouver rat SNP GenotypesPLINK .map file for Vancouver SNP genotypes. The genotypes themselves are in the .ped file of the same name, and the .map file contains the chromosomal coordinates for each SNP.VAN.plink.mapPLINK .ped file for Vancouver rat SNP GenotypesPLINK .ped file for Vancouver SNP genotypes. The genotypes themselves are in the .ped file, and the .map file contains the chromosomal coordinates for each SNP.VAN.plink.ped

IntroductionClimate Central’s Surging Seas: Risk Zone map shows areas vulnerable to near-term flooding from different combinations of sea level rise, storm surge, tides, and tsunamis, or to permanent submersion by long-term sea level rise. Within the U.S., it incorporates the latest, high-resolution, high-accuracy lidar elevation data supplied by NOAA (exceptions: see Sources), displays points of interest, and contains layers displaying social vulnerability, population density, and property value. Outside the U.S., it utilizes satellite-based elevation data from NASA in some locations, and Climate Central’s more accurate CoastalDEM in others (see Methods and Qualifiers). It provides the ability to search by location name or postal code.The accompanying Risk Finder is an interactive data toolkit available for some countries that provides local projections and assessments of exposure to sea level rise and coastal flooding tabulated for many sub-national districts, down to cities and postal codes in the U.S. Exposure assessments always include land and population, and in the U.S. extend to over 100 demographic, economic, infrastructure and environmental variables using data drawn mainly from federal sources, including NOAA, USGS, FEMA, DOT, DOE, DOI, EPA, FCC and the Census.This web tool was highlighted at the launch of The White House's Climate Data Initiative in March 2014. Climate Central's original Surging Seas was featured on NBC, CBS, and PBS U.S. national news, the cover of The New York Times, in hundreds of other stories, and in testimony for the U.S. Senate. The Atlantic Cities named it the most important map of 2012. Both the Risk Zone map and the Risk Finder are grounded in peer-reviewed science.Back to topMethods and QualifiersThis map is based on analysis of digital elevation models mosaicked together for near-total coverage of the global coast. Details and sources for U.S. and international data are below. Elevations are transformed so they are expressed relative to local high tide lines (Mean Higher High Water, or MHHW). A simple elevation threshold-based “bathtub method” is then applied to determine areas below different water levels, relative to MHHW. Within the U.S., areas below the selected water level but apparently not connected to the ocean at that level are shown in a stippled green (as opposed to solid blue) on the map. Outside the U.S., due to data quality issues and data limitations, all areas below the selected level are shown as solid blue, unless separated from the ocean by a ridge at least 20 meters (66 feet) above MHHW, in which case they are shown as not affected (no blue).Areas using lidar-based elevation data: U.S. coastal states except AlaskaElevation data used for parts of this map within the U.S. come almost entirely from ~5-meter horizontal resolution digital elevation models curated and distributed by NOAA in its Coastal Lidar collection, derived from high-accuracy laser-rangefinding measurements. The same data are used in NOAA’s Sea Level Rise Viewer. (High-resolution elevation data for Louisiana, southeast Virginia, and limited other areas comes from the U.S. Geological Survey (USGS)). Areas using CoastalDEM™ elevation data: Antigua and Barbuda, Barbados, Corn Island (Nicaragua), Dominica, Dominican Republic, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, San Blas (Panama), Suriname, The Bahamas, Trinidad and Tobago. CoastalDEM™ is a proprietary high-accuracy bare earth elevation dataset developed especially for low-lying coastal areas by Climate Central. Use our contact form to request more information.Warning for areas using other elevation data (all other areas)Areas of this map not listed above use elevation data on a roughly 90-meter horizontal resolution grid derived from NASA’s Shuttle Radar Topography Mission (SRTM). SRTM provides surface elevations, not bare earth elevations, causing it to commonly overestimate elevations, especially in areas with dense and tall buildings or vegetation. Therefore, the map under-portrays areas that could be submerged at each water level, and exposure is greater than shown (Kulp and Strauss, 2016). However, SRTM includes error in both directions, so some areas showing exposure may not be at risk.SRTM data do not cover latitudes farther north than 60 degrees or farther south than 56 degrees, meaning that sparsely populated parts of Arctic Circle nations are not mapped here, and may show visual artifacts.Areas of this map in Alaska use elevation data on a roughly 60-meter horizontal resolution grid supplied by the U.S. Geological Survey (USGS). This data is referenced to a vertical reference frame from 1929, based on historic sea levels, and with no established conversion to modern reference frames. The data also do not take into account subsequent land uplift and subsidence, widespread in the state. As a consequence, low confidence should be placed in Alaska map portions.Flood control structures (U.S.)Levees, walls, dams or other features may protect some areas, especially at lower elevations. Levees and other flood control structures are included in this map within but not outside of the U.S., due to poor and missing data. Within the U.S., data limitations, such as an incomplete inventory of levees, and a lack of levee height data, still make assessing protection difficult. For this map, levees are assumed high and strong enough for flood protection. However, it is important to note that only 8% of monitored levees in the U.S. are rated in “Acceptable” condition (ASCE). Also note that the map implicitly includes unmapped levees and their heights, if broad enough to be effectively captured directly by the elevation data.For more information on how Surging Seas incorporates levees and elevation data in Louisiana, view our Louisiana levees and DEMs methods PDF. For more information on how Surging Seas incorporates dams in Massachusetts, view the Surging Seas column of the web tools comparison matrix for Massachusetts.ErrorErrors or omissions in elevation or levee data may lead to areas being misclassified. Furthermore, this analysis does not account for future erosion, marsh migration, or construction. As is general best practice, local detail should be verified with a site visit. Sites located in zones below a given water level may or may not be subject to flooding at that level, and sites shown as isolated may or may not be be so. Areas may be connected to water via porous bedrock geology, and also may also be connected via channels, holes, or passages for drainage that the elevation data fails to or cannot pick up. In addition, sea level rise may cause problems even in isolated low zones during rainstorms by inhibiting drainage.ConnectivityAt any water height, there will be isolated, low-lying areas whose elevation falls below the water level, but are protected from coastal flooding by either man-made flood control structures (such as levees), or the natural topography of the surrounding land. In areas using lidar-based elevation data or CoastalDEM (see above), elevation data is accurate enough that non-connected areas can be clearly identified and treated separately in analysis (these areas are colored green on the map). In the U.S., levee data are complete enough to factor levees into determining connectivity as well.However, in other areas, elevation data is much less accurate, and noisy error often produces “speckled” artifacts in the flood maps, commonly in areas that should show complete inundation. Removing non-connected areas in these places could greatly underestimate the potential for flood exposure. For this reason, in these regions, the only areas removed from the map and excluded from analysis are separated from the ocean by a ridge of at least 20 meters (66 feet) above the local high tide line, according to the data, so coastal flooding would almost certainly be impossible (e.g., the Caspian Sea region).Back to topData LayersWater Level | Projections | Legend | Social Vulnerability | Population | Ethnicity | Income | Property | LandmarksWater LevelWater level means feet or meters above the local high tide line (“Mean Higher High Water”) instead of standard elevation. Methods described above explain how each map is generated based on a selected water level. Water can reach different levels in different time frames through combinations of sea level rise, tide and storm surge. Tide gauges shown on the map show related projections (see just below).The highest water levels on this map (10, 20 and 30 meters) provide reference points for possible flood risk from tsunamis, in regions prone to them.