Description: <DIV STYLE="text-align:Left;"><DIV><P><SPAN>This data set is a polygon coverage of the cumulative thickness of Zone 1, in feet, over extent of the Zone 1 coal and its horizon (stratigraphic equivalent) in Northeast Texas only. The coverage was produced by gridding more than 150 public and confidential point-source data from the National Coal Resources Data System (NCRDS) of the USGS, using EarthVision (Version 4.0.2) software, subsequently contoured into 6-inch intervals, and imported to ARC/INFO. The 'thickness' item for each polygon reflects a value in feet halfway between the bounding contour lines. This value represents results of gridding which averages point values within cells, therefore, public point data may not always match values represented in the isopach data layer.</SPAN></P></DIV></DIV>
Service Item Id: e1db7cf3c6444db3bee871944cd47294
Copyright Text: The stratigraphic data stored in the NCRDS has been submitted by
State Geological Surveys and USGS scientists since its inception
in the middle 1970's through state cooperative programs. The data
for the Zone 1 coal bed was used with the permission and through
the cooperation of coal geologists (primary contacts listed) at the
State of Texas Bureau of Economic Geology and the State of Texas
Railroad Commission