<div class="description">
Chiefly maps.; Includes bibliographical references.; "A digital elevation map (DEM), generated from LiDAR (Light Detection and Ranging) data, was used to create a map layer that identified low, enclosed areas. To locate potential sinkholes, these low spots were cross referenced with known karst points, bedrock geology, aerial photography of multiple sources and ages, soil maps, glacial drift thickness maps, and water well logs. Suspect locations then were then visited in the field, evaluated, and photographed. Through this process some of the LiDAR returns were found not to be sinkholes; features such as building foundations, broken field tiles, steep-walled streams, road culverts, and glacial features often produced enclosed areas similar in shape to sinkholes. Many of these misleading features were eliminated remotely using both 6-inches-per pixel aerial photography and experience from past field verification. However, many points remained that could not be distinguished remotely and these were visited in the field."--Page 1.</div>
2014
This file was contributed to Wikimedia Commons by <a href="https://en.wikipedia.org/wiki/en:State_Library_of_Ohio" class="extiw" title="w:en:State Library of Ohio"><span title="library">State Library of Ohio</span></a> as part of a cooperation project. The donation was facilitated by the <a href="https://en.wikipedia.org/wiki/Digital_Public_Library_of_America" class="extiw" title="w:Digital Public Library of America">Digital Public Library of America</a>, via its partner Ohio Digital Network.<span style="text-align:left">
<ul><li><a rel="nofollow" class="external text" href="http://www.ohiomemory.org/cdm/ref/collection/p267401ccp2/id/13473">Record in source catalog</a></li>
<li>DPLA identifier: <a rel="nofollow" class="external text" href="https://dp.la/item/de6f5147ee2c257bcf926f8131adb6ac">de6f5147ee2c257bcf926f8131adb6ac</a></li>
<li>State Library of Ohio identifier: <a rel="nofollow" class="external free" href="http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/OpenFileReports/OFR_2014-1.pdf">http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/OpenFileReports/OFR_2014-1.pdf</a>; 944127981</li></ul></span>