Geographic extent of the Middle Devonian Marcellus Shale in the northeastern U.S. (Appalachian Basin) with indication of the thickness (in feet).
<a href="//commons.wikimedia.org/wiki/User:Gretarsson" title="User:Gretarsson">Gretarsson</a>
CC BY-SA 4.0
<p><span class="int-own-work" lang="en">Own work</span>
The map was created using QGIS, with minor revisions using Adobe Photoshop.<br>
Data sources:
</p>
<ul><li>Geology: shapefile ‘Tight Oil and Shale Gas by Individual Play’ (March 2019), provided by the U.S. Energy Information Administration (download URL: <a rel="nofollow" class="external free" href="https://www.eia.gov/maps/map_data/TightOil_ShaleGas_IndividualPlays_Lower48_EIA.zip">https://www.eia.gov/maps/map_data/TightOil_ShaleGas_IndividualPlays_Lower48_EIA.zip</a>)</li>
<li>State and country borders: shapefiles (2018) provided by the U.S. Census Bureau (download URLs: <a rel="nofollow" class="external free" href="https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_state_5m.zip">https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_state_5m.zip</a>, <a rel="nofollow" class="external free" href="https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_nation_5m.zip">https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_nation_5m.zip</a>)</li>
<li>Geographical features (large lakes only): a selection of OpenStreetMap data (shapefiles, as of 21 August 2019), provided at Geofabrik (<a rel="nofollow" class="external free" href="http://download.geofabrik.de/north-america.html">http://download.geofabrik.de/north-america.html</a>)</li>
<li>Background: hillshade layer, generated from SRTM-based (SRTM GL3, 90 m resolution) digital elevation model, all provided at OpenTopography (<a rel="nofollow" class="external free" href="http://opentopo.sdsc.edu/raster?opentopoID=OTSRTM.042013.4326.1">http://opentopo.sdsc.edu/raster?opentopoID=OTSRTM.042013.4326.1</a>)</li></ul>
All data are either originally published/provided by the U.S. federal government (EIA, USCB, NASA/USGS) and thus are in the <a href="https://en.wikipedia.org/wiki/Public_domain" class="extiw" title="w:Public domain">public domain</a> or are generated by Open StreetMap contributors and distributed under the <a rel="nofollow" class="external text" href="https://www.opendatacommons.org/licenses/odbl/1.0/index.html">Open Database 1.0 License</a> which allows free use, modification and re-distribution.