Skip to main content
  1. ScienceBase Catalog
  2. Eastern Ecological Science Center
  3. xLegacy Data Releases
  4. Patuxent Wildlife Research Center
  5. EPA 40km Hexagons for Conterminous United States

EPA 40km Hexagons for Conterminous United States

Dates

Publication Date
Time Period
1992
Release Date
1992

Citation

White, D., and U.S. Environmental Protection Agency, 1992, EPA 40km Hexagons for Conterminous United States: U.S. Geological Survey data release, https://doi.org/10.5066/P9C56AY1.

Summary

This dataset of 40 square kilometer (sq. km) hexagons was created by the U.S. EPA's Environmental Monitoring and Assessment Program (EMAP) and is being released by the U.S. Geological Survey for public use. The 40 sq. km hexagons were derived from a grid consisting of a triangular array of points that cover the United States and neighboring Canada and Mexico. The base grid of points had a companion areal structure called a tessellation. The base tessellation hexagons constituted this tessellation. In other words, surrounding each grid point was a hexagon that defines the area within which all points are closer to this grid point than to any other, and the set of hexagons defined this way completely and -mutually exclusively covers [...]

Contacts

Point of Contact :
Allison Sussman
Originator :
Denis White, U.S. Environmental Protection Agency
Metadata Contact :
Allison Sussman, Meghan C Eyler
Distributor :
U.S. Geological Survey - ScienceBase
CMS Group :
Patuxent Wildlife Research Center
USGS Mission Area :
Ecosystems
SDC Data Owner :
Eastern Ecological Science Center

Attached Files

Click on title to download individual files attached to this item.

EMAPgrid_readme.txt
“Original Read Me file for 40-sq km hexagon sampling grid” 		14.01 KB text/plain
Overton_etal_1991.PDF
“Original design report on the EMAP sampling grid” 		2.29 MB application/pdf
Spence+White_EMAPgrid_TechRpt_1992.pdf
“Original technical report on the EMAP sampling grid” 		135.07 KB application/pdf
White_2000.pdf
“Global grid using a diamond tessellation for environmental sampling and modeling” 		6.34 MB application/pdf
White_etal_CAGIS_1992.pdf
“A sampling design created to address a wide variety of environmental issues” 		2.4 MB application/pdf
Shapefile: EPA_Hexagons_40km.zip
EPA_Hexagons_40km.shp.xml
Original FGDC Metadata
View 		16.13 KB
EPA_Hexagons_40km.dbf 14.5 MB
EPA_Hexagons_40km.prj 484 Bytes
EPA_Hexagons_40km.sbn 2.99 MB
EPA_Hexagons_40km.sbx 161.01 KB
EPA_Hexagons_40km.shp 54.15 MB
EPA_Hexagons_40km.shx 2.58 MB

Purpose

The original hexagon layer was created because hexagons: • Reduce sample bias, and are the closest shape to a circle that can tessellate • Are a preferable shape for connectivity or movement path analysis • Visually break artificial linear patterns, diminish any orientation bias found with square grids • Have less distortion over large distances (curvature of Earth) • Make finding neighbors more straightforward (e.g., hotspot analysis, outlier analysis) The U.S. Fish and Wildlife Service has been using the 40 sq. km hexagon tessellation for a multi-agency project in the Gulf of Mexico, and has received numerous requests for the hexagon layer for other projects and research. Because the layer is no longer available online through the EPA, the USGS and USFWS are releasing the layer so that it may be distributed and accessed by those interested parties.

Map

Map Preview

Spatial Services

ScienceBase WMS

ScienceBase WFS

Communities

  • Eastern Ecological Science Center
  • Patuxent Wildlife Research Center

Tags

Provenance

Additional Information

Identifiers

Type Scheme Key
DOI https://www.sciencebase.gov/vocab/category/item/identifier doi:10.5066/P9C56AY1

Shapefile Extension

boundingBox
minY22.49933072271044
minX-128.80165142226474
maxY51.96091332302376
maxX-64.43100056624453
files
nameEPA_Hexagons_40km.dbf
contentTypetext/plain
pathOnDisk__disk__5b/1a/92/5b1a92b6174b68fd5a2026f4bd09237c56f9fdef
imageWidth580
imageHeight435
size15209230
dateUploadedMon Dec 10 13:03:59 MST 2018
nameEPA_Hexagons_40km.prj
contentTypetext/plain
pathOnDisk__disk__10/62/ff/1062ff69906b748dd3e79fc6d9fed838d01c5204
imageWidth580
imageHeight435
size484
dateUploadedMon Dec 10 13:03:33 MST 2018
nameEPA_Hexagons_40km.sbn
contentTypex-gis/x-shapefile
pathOnDisk__disk__67/b2/ff/67b2ff6dc1dd6d1c559f2b9ef1b24006ca72ed2b
size3130324
dateUploadedMon Dec 10 13:03:37 MST 2018
nameEPA_Hexagons_40km.sbx
contentTypex-gis/x-shapefile
pathOnDisk__disk__11/d4/d6/11d4d677af6220a058a72c0068ac2abde8806e57
size164876
dateUploadedMon Dec 10 13:03:33 MST 2018
nameEPA_Hexagons_40km.shp
contentTypex-gis/x-shapefile
pathOnDisk__disk__87/14/80/8714809cc31c449475c5ea77609beba20cad3fb9
size56780740
dateUploadedMon Dec 10 13:05:39 MST 2018
nameEPA_Hexagons_40km.shx
contentTypex-gis/x-shapefile
pathOnDisk__disk__91/83/45/9183456f31a043d57e7778e464e1aad2b776dced
size2703940
dateUploadedMon Dec 10 13:03:39 MST 2018
nameEPA_Hexagons_40km.shp.xml
contentTypeapplication/fgdc+xml
pathOnDisk__disk__c4/a0/39/c4a039a7a387dd966264466422585e4f120acbf5
dateUploadedMon Dec 28 16:02:38 MST 2020
originalMetadatatrue
checksum
value61427ca6ed3c0ebd3a6d0c045743179c
typeMD5
geometryTypeMultiPolygon
nameEPA_Hexagons_40km
nativeCrsEPSG:102004

Item Actions

Use Item

Process feature with Geo Data Portal

View Item as ...

JSON ATOM ISO XML

Save Item as ...

JSON FGDC MODS XML ISO XML

View Item...

Metrics