This data set was compiled by Indiana University, Indiana Geological Survey, using data believed to be accurate; however, a degree of error is inherent in all data. This product is distributed "AS-IS" without warranties of any kind, either expressed or implied, including but not limited to warranties of suitability to a particular purpose or use. No attempt has been made in either the design or production of these data to define the limits or jurisdiction of any federal, state, or local government. These data are intended for use only at the published scale or smaller and are for reference purposes only. They are not to be construed as a legal document or survey instrument. A detailed on-the-ground survey and historical analysis of a single site may differ from these data.
CREDIT:
It is requested that the dataset be cited in any products generated from this data. The following source citation should be included: [Bedrock_Contours_Maumee_Basin_IGS_IN: Bedrock Topography, 2012 (Indiana Geological Survey, 1:200,000, ESRI Shapefile)].
WARRANTY:
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY:
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.
Contour lines were drawn at various scales and contain attribute error concordant with the scale at which they were drawn as well as the availability and quality of the point data from which they were interpreted.
The accuracy of elevation values that were manually assigned to digitized streamlines is subject to the judgement of IGS personnel and the quality of the data used to infer said elevation values.
Contour lines were drawn at various scales and contain horizontal positional error concordant with the scale at which they were drawn as well as the availability and quality of the point data from which they were interpreted.
Some of the water well point data used in the creation of this data set were not GPS located on site. The following is excerpted from metadata provided by the IDNR and describes the horizontal accuracy for water well point data lacking field-collected GPS coordinates:
"Locations based only on the street address, driving directions, or other location information provided on the well record are considered unlocated records and have no x, y coordinates, only township, range, section, and quarter-quarter-quarter sections (if estimated).
"The x, y coordinates are from the calculated centroid of the smallest possible individual polygon that matched the water well location data. Some records have no quarter sections and/or some of the polygons could not be subdivided, so the centroid of the section was used for those water well records. These are the least accurate coordinates and in a regular one-mile square section the x, y coordinates will generally be within a half-mile of the office located section, on irregular sections, the distance may be greater. The best location values are on the records with quarter-quarter-quarter sections and typically will be within 150 meters of the office located quarters.
"A small number of the data points were checked for accuracy and methods used should keep the x, y coordinates within the proper section in most cases. However, due to the complexity and in cases redundancy in the public land survey system for Indiana some x, y pairs may not be located in the proper section or even the proper county. Other sources of error may be caused by misinterpretation of the driving directions or office locating. Several areas have different survey systems than the Congressional TRS (Clark Military Grant, Military Donations, Meridian Road Lines, Indian Treaties etc.) and no attempt at this time was made to provide centroids for these areas.
"Located records were primarily field located based on the location identified on the USGS 1:24,000 7.5 minute series topo map by the field locator. In some cases the structure or subdivsion may not be on the map and location is based on topography. So some error may be inherent in the field locations and points placed on the map ( a single point on a map may be 100 feet across). The scale is based USGS 1:24,000 7.5 minute series topographic maps. However, in most cases locations of mislocated wells can have large errors, with the reported locations having no meaning."
A continuous bedrock surface model named "Maumee_1" was interpolated for the Maumee watershed region using the "TopoToRaster" tool of ESRI ArcToolbox. Input data included ESRI shapefiles whose features, whether points representing boreholes or polylines representing contours, contain explicit bedrock elevation values. The names of these input shapefiles are as follows: "BR_Boreholes_2012," "uncobot_4_revised," "OH_btcontours_NAD83," "StJoe_BRT_polyline," "North_IN_BRT_contours," "Mich_BR_wells_NAD83," and "Maumee_TF_Contours_merge."
In addition to the borehole data containing explicit bedrock elevation values, boreholes composed purely of unconsolidated sediment were also utilized in the creation of this data set. A purely unconsolidated borehole entails an absence of any significantly thick layer of consolidated material at any point in the vertical record. Hence, only those unconsolidated boreholes whose vertical thickness extended below the surface of the model "Maumee1" were utilized. It should be noted that the bedrock elevation values of the unconsolidated borehole data points are only implied. That is, their elevation values can be conceptualized as a minimum bedrock elevation, but in actuality the bedrock surface may lie deeper. The steps by which these deep unconsolidated borehole data points were identified are described below.
STEP 1: Using the "Extract Values to Points" tool of ESRI ArcToolbox, extract the values from "Maumee1" to the attribute table of the point shapefile named "UNC_Boreholes_2012"
STEP 2: Select unconsolidated boreholes (from UNC_Boreholes_2012.shp) whose elevation at the bottom of the unconsolidated sediment is deeper than the bedrock surface of the model "Maumee1"
STEP 3: Export the selected point features from UNC_Boreholes_2012.shp as a new shapefile titled "UNC_Boreholes_2012_Deeper"
Another bedrock model was interpolated using the "TopoToRaster" Tool of ESRI ArcToolbox and with the shapefile named "UNC_Boreholes_2012_Deeper" included in addition to all of the input data from the first process step. The output raster model was named "Maumee2."
Drainage networks could be observed throughout the bedrock surface displayed by the model named "Maumee2". However, in some areas the input data struggled to create pronounced drainage routes, mostly due to the issue of scarce point density. The aim of this process step was to further accentuate the apparent, but under-pronounced drainage networks shown in the model. This was acheived by connecting strings of borehole points with similar elevation values while using subjective geologic knowledge to infer the directionality of drainage routes. Three polyline shapefiles were edited in this process step: "Teays_Main_Channel," "Metea_Valley_Section_wElevs," and "LaFontaine_Section."
A final bedrock surface model was interpolated using the digitized drainage polylines (i.e. "Teays_Main_Channel," "Metea_Valley_Section_wElevs," and "LaFontaine_Section") from the previous step as well as all of the data sets from the third process step. The output raster model was named "Maumee3."
Within ESRI ArcMap, an ordinary least squares (OLS) regression was performed to test how well the interpolated model, "Maumee3," fit the actual bedrock elevation values of the point data. To do this, the three different point data sets (i.e. "BR_Boreholes_2012," "Mich_BR_wells_NAD83," and "UNC_Boreholes_2012_Deeper") needed to be merged into a single shapefile. Additionally, those points needed to have the values of the underlying model (i.e. "Maumee3") attached to their attribute table. The steps are described below.
STEP 1: Standardize the field headers and field data types from the attribute tables of "BR_Boreholes_2012," "Mich_BR_wells_NAD83," and "UNC_Boreholes_2012_Deeper" so that a merge operation is possible. The fields containing bedrock elevation values were renamed to have the common alias "BR_Z_FT."
STEP 2: Use the "Merge" tool of ESRI ArcToolbox to combine "BR_Boreholes_2012," "Mich_BR_wells_NAD83," and "UNC_Boreholes_2012_Deeper" into a single output shapefile named "Maumee_Boreholes_Merged."
STEP 3: Using the "Extract Values to Points" tool of ESRI ArcToolbox, attach the underlying values of "Maumee3" to the attribute table of the point features in the shapefile named "Maumee_Boreholes_Merged," the name of the attached field being "RASTERVALU."
STEP 4: Run an OLS regression on "Maumee_Boreholes_Merged" with the field named "BR_Z_FT" as the dependent variable and the field named "RASTERVALU" as the independent variable. The output was a new shapefile named "Maumee_Boreholes_w_Stats" along with a table containing descriptive statistics such as the coefficient of determination (i.e. r-squared value).
The coefficient of determination (goodness of fit) between the model and actual point data was 0.91. This statistic would be closer to 100% if the only independent variables were the same points as the points of the dependent variable, but not all emphasis was placed on point data. Rather, contours were incorporated to create a more fluid and realistically behaving bedrock surface model.
This process step describes how bedrock elevation contours were generated, edited, and finalized for the creation of this data set.
STEP 1: From the raster model named "Maumee3," an ESRI polyline shapefile depicting bedrock elevation contours for the Maumee watershed region was created, its name being "Maumee_Wtrshed_BR_Contours_1." To create this shapefile, the "Contour" tool of ESRI ArcToolbox was utilized with the "Maumee 3" model as input, "Maumee_Wtrshed_BR_Contours_1" as output, and a contour interval of 40 feet was established.
STEP 2: The lengths (in meters) of contour line features were calculated, creating a field named "Shape_Length" in the attribute table of "Maumee_Wtrshed_BR_Contours_1." This field was then sorted and those features whose lengths were less than 5000 meters were selected then deleted. The intention was to remove unwanted detail (i.e. contouring of very small basins) produced by the "Contour" tool.
STEP 3: The "Simplify Line" tool of ESRI ArcToolbox was used on "Maumee_Wtrshed_BR_Contours_1" to remove vertices that weren't critical to preserving the shapes of contour line features. This had a generalizing effect on the contours because some detail was reduced with the deletion of vertices. The output shapefile produced by this operation was named "Maumee_Wtrshed_BR_Contours_2."
STEP 4: The "Smooth Line" tool of ESRI Arctoolbox was used on "Maumee_Wtrshed_BR_Contours_2" to, as the name entails, smooth the contour lines. The smoothing algorithm used was that of a bezier interpolation, which adds curvature while maintaining that contour lines run through the original vertices. The output from this operation was a shapefile named "Maumee_Wtrshed_BR_Contours_3."
STEP 5: The "Dissolve" tool of ESRI ArcToolbox was used on "Maumee_Wtrshed_BR_Contours_3" to merge topologically connected line features into single contours. The output from this operation was a shapefile named "Maumee_Wtrshed_BR_Contours_4."
STEP 6: "Maumee_Wtrshed_BR_Contours_4" was clipped to the boundary of the Maumee watershed region using the "Clip" tool of ESRI ArcToolbox. The output of this operation was a shapefile named "Bedrock_Contours_Maumee_Basin_IGS_IN," which is the final product of the process steps and the data set for which this metadata was written.
This metadata file was pre-parsed and parsed using CNS (Chew and Spit, v. 2.6.1) and MP (Metadata Parser, v. 2.7.1) software written by Peter N. Schweitzer (U.S. Geological Survey). The errors generated by MP were all addressed and corrected.
It is requested that the dataset be cited in any products generated from this data. The following source citation should be included: [Bedrock_Contours_Maumee_Basin_IGS_IN: Bedrock Topography, 2012 (Indiana Geological Survey, 1:200,000, ESRI Shapefile)].
WARRANTY:
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY:
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.