Karst Potential Classification
The karst potential map shows the tendency for geologic units to develop or have karst features such as sinkholes, springs, caves, or other solution features.
The classification is based on lithology. The lithologic characteristics used are percentage of CaCO3 in the carbonate portion of the unit, grain size,
bedding thickness, and insoluble components. Insoluble components may occur as a mineral grains within the limestone lithology or as interbeds of noncarbonate rock.
These criteria were evaluated for all rock units and combined rock units that appear on the map, and resulted in about 50 distinct rankings.
These rankings were reduced to three to five simplified classes by analysis of their frequency of distribution and the scale of the map data.
|1:500,000 (small scale) map data (viewed at scales 1:150,001 and smaller) displays three classes:|
Areas underlain by bedrock with high potential for karst development. May exhibit mature karst, including caves, sinkholes, and springs where they crop out.
Areas underlain by bedrock with moderate potential for karst development. Development of karst features in this category is variable and dependent on site-specific conditions.
Occurrence of caves may be influenced by physiographic setting, unit thickness, and lithology.
Areas underlain by bedrock with limited or no potential for karst development. Karst features rare or absent.
|1:24,000 (large scale) map data (viewed at scales 1:150,000 and greater) displays five classes:|
Thick-bedded, typically fine-grained and pure limestone units with little or no insoluble content. Will exhibit mature karst, including caves, sinkholes, and springs where they crop out.
Limestone units with low insoluble content, but varied grain size and bedding characteristics. Likely to contain karst features. Occurrence of caves may be influenced by physiographic setting, unit thickness, and lithology.
Limestone units and coarse-grained, or siliciclastic units with limestone interbeds. Limestone units may contain a high percentage of insoluble minerals.
Siliciclastic units will only be karst-prone where limestone beds occur in the near surface. Development of karst features in this category is variable and dependent on site-specific conditions.
Siliciclastic units with minor limestone beds or units primarily composed of dolomite. Karst features are poorly developed or absent.
Consolidated or unconsolidated siliciclastic units. Karst features rare or absent.
|Two different sinkholes layers are displayed in this layout:|
Statewide Sinkhole Outlines
These data represent digital GIS sinkhole coverage for all of Kentucky. The highest elevation, closed, topographic contour of each mapped
sinkhole was digitized as a GIS polygon. The second highest elevation contour was also digitized where very large, shallow, karst valleys
were so expansive that the area covered by the polygon obscured patterns in sinkhole distribution.
These karst valleys are mostly confined to the Western Pennyroyal. The spacing of contour intervals on the topographic maps of the state vary
in from 40 foot to 10 foot. No attempt was made to use a constant elevation, standardize the outline to a uniform contour interval, or
record the elevation of the digitized contour. Digitization was done onscreen using digital raster graphic files of the 7.5-minute topographic contours,
registered and projected to the Kentucky State Plane coordinate system.
LiDAR-derived Sinkhole Outlines
The sinkhole maps are derived from LiDAR data using ArcGIS 10.1. LiDAR data were used to create digital elevation model (DEMs).
Surface depressions were then extracted from the DEMs and visually inspected for sinkholes. Field verification suggests that the accuracy of the
identified sinkholes to be real sinkholes is over 85%. The data provided here are provisional and updates will be provided if needed. LiDAR data were
provided by the Louisville/Jefferson County Information Consortium (LOJIC) through Kentucky Division of Geographic Information.
The LiDAR was flown in August, 2009 and the average point spacing is 1.0 meter. DEMs were created using LAS Class 2 surface with 5 feet resolution.
Each sinkhole is presented as a polygon feature and the attribute table contains the following fields:
SinkholeID: an 8-digit numerical code, in which the left three digits represent FIPS county code and the remaining five digits are sequential.
Latitude: latitude of the centroid of the sinkhole
Longitude: longitude of the centroid of the sinkhole
Area_sqft: the approximate surficial area of the sinkhole
County: County location of the sinkhole
Method: the method used for identifying the sinkhole
Field Verified: Show if the sinkhole is checked and verified in the field.
Geologic Map Service Tutorials:
Overview of Map Functionality
Most of the map functionality is provided in the tabs on the right-side of the map interface:
The tool tab contains standard tools for zoom and pan control of the map. In addition there are several custom tools:
- The button opens a tool which allows the user to search by and zoom to a
geographic area in Kentucky. The types of geographic areas which a user can search by include county name, coordinate location, stream or road name, etc...
- The button opens a table of links to other internet map services or
databases in Kentucky. Selecting a service from the table will open it in another window, zoomed to the same extent of the geologic map.
tool will return a quick popup window that provides information about visible features from the "Geology" and "Data"
layers (e.g. geologic faults, contacts, faults, oil and gas wells, water wells, etc). When used, the feature(s) will be highlighted and basic attribute
information displayed in the popup. Be sure to use the left and right arrow icons at the top of the window to scroll through the identified features if
more than one is found at a location.
- The tool is a query tool that returns information about features on the map at a point.
Clicking on a geologic unit provides lithologic descriptions and, in some cases, economic, geotechnical, hydrologic, or other descriptions. Clicking on an overlay feature
(e.g., oil well or quarry outline) provides summary information about the feature with links to additional data.
returns the same information as the point id tool, but for a rectangular search area drawn by the user.
- The tool is an id tool that returns all the information about a selected point layer (layer selection can be
made when the tool is activated, and include layers such as coal boreholes, wells, photos, etc.) within a buffered area around the selected point on the map.
- The will return photos taken at locations on the map which are designated by the images symbols. For this tool to function and to view the photo icons on the map, the "Photo Locations" must be turned on as a map layer.
- The tool is a measuring tool which returns the distance in feet and miles for a line drawn on the map.
- The tool is a measuring tool which returns the area and distance in feet and miles for a polygon drawn on the map.
- The tool is a click tool that returns the coordinate and descriptive location for a point on the map.
- The print tool creates a formatted print page for the map window.
- The print tool creates a formatted pdf page for the map window.
A note about map printing:
For best results, use the latest version of Internet Explorer, Firefox, or Google Chrome browsers.
NOTE: In older versions of Internet Explorer (8.0 and below), the topography or imagery may not print. You will need to either
upgrade your browser, use a different browser (Firefox or Chrome), use the "print to pdf" tool, or use your computer's screen capture functionality.
- The print tool creates a formatted legend for printing.
This functionality allows you to search the Kentucky Geological Survey database for geologic descriptions from KGS publications, maps, and field notes and highlight those units on the map.
Follow the instructions on the tab for more information about using this feature.
This tab provides explanations of symbology for the map layout. The map unit colors display the map colors for the units in the viewed extent. Other map symbols
are displayed below the colors and are also displayed with each map layer on the "Layers" tab.
This tab provides controls for changing the layout of the map. There are three main sections in this tab:
- Base Layers:
The map service has a basic basemap which includes mostly line features such as roads and streams. Using the buttons at
the top of this section, users may turn on topography with hillshade, topography without hillshade, an aerial photo base, or just
display the basemap. The basemap (roads, rivers, etc..) transparency can also be adjusted with the slider. Other basemap-type layers, including
various index maps for quadrangles and milepoints for roads and streams, can be turned on/off in the menus below the transparency slider.
- Quick Map Layouts:
Clicking the buttons within this section will refresh the entire map service to a standard map layout. The webpage will refresh and the map will zoom to the same location and
layers are selected/deselected based on the layout design. The "bookmark" link allows the user to save the currently selected map layout and extent.
- Customize Map:
In this section, the geologic map and data layers can be turned on/off, their transparency can be altered, and, in some cases, the user can select how features are labeled.
Simply turn on and off layers by selecting and deselecting the checkbox next to each layer name. The "Geology" layers are bundled within one service and have the same transparency settings.
The "Data Layers" are mostly point features of geologically-related data. Each data layer has their own transparency setting and, if applicable, labeling.
Also displayed under each activated data layer are the map symbols for that layer. Clicking the icon that is
next to each data layer will open the ArcGIS Server service info and metadata for that layer.
You can also bring these layers into your own GIS (e.g. ArcGIS) by following the instructions at this link.
There are two ways to get information about geologic units or other features on the map. The identity tool
, described above, is used to gather information about specific features. It works by clicking on the map
and the results are sent to a pop-up window. The identity tool only returns descriptions from the 1:24,000-scale GQ's. Be aware that the sensitivity of the tool is scale-dependant. Clicking at
small scales may return descriptions for multiple map units or features.
The Geologic Information tab provides comprehensive searches for all information that pertains to the map extent. Because of the larger amount of information that is accessed, the searches
are provided from individual links. The results are grouped by type of source and then by the individual source title. The source title is a link to the KGS online list of publications, where
many publications can be viewed. For lithology descriptions, a portion of the graphic stratigraphic column is provided for context, and the full stratigraphic column is accessed from a link.