General Metadata for Scanned Map Images

Source maps are provided to the Kentucky Division of Mine Safety (DMS) by the mining companies or their engineers in accordance with KRS 352.450. The accuracy of the source maps has not been verified beyond any certifications that may appear on the original paper map.

Each map is accompanied by a processing metadata file that provides information on how the map was handled during each step of scanning and geoprocessing. This metadata file is formatted in ASCII text and is named as follows:


and contains the following information:

  1. Scanning and Initial Processing Metadata

    1. Scanning:

      Scanned Images of the original mine maps have been created by scanning the original maps on a large format scanner at a resolution of 200, 300, or 400 dpi using 24 bit RGB color, Joint Photographic Experts Group (JPEG) format. A small percentage of maps too large to be scanned by a single pass are either folded or sliced into the minimum number of sections required to cover the entire map area, and the resulting image files are "stitched" (merged digitally) to form a single image.

      SourceImageDateTime=2/18/2008 3:13:42 PM

    2. Stage1 Clean-up

      All map images are cropped, rotated to a text up readable position, and checked for errors during Stage1 Clean-up prior to being saved to archive.

      Stage1CleanupDateTime=2/19/2008 9:02:09 AM

    At this point the map jpg image file is suitable for archiving purposes and is considered the master image document.

  2. Geoprocessing

    Geoprocessing requires additional image editing to prepare the map image for suitable use in a geographic information systems (GIS) or computer aided design (CAD) environment. This additional editing includes removal of background 'noise' usually caused by deterioration of the map media, and enhancing faded linework so that features are easily readable. Another benefit of this cleanup work is the resulting image background being comprised of pixels having the same color value, thus facilitating lossless image file compression.

    1. Stage2 Clean-up

      Additional image processing is applied to a copy of the achived map image prior to registration and georeferencing of map images. Quality control checks are conducted during this step as well.

      Stage2CleanupDateTime=2/19/2008 11:51:01 AM

    2. Colormap Indexing

      The image resulting from the Stage2 Clean-up process is then color processed to an 8 bit index, 128 color adaptive palette Tagged Image File Format (TIFF) which results in all colors comprising the original map image being reduced to a best fit 128 color scheme for that particular map. The map image is also resampled to 200 dpi to reduce the computational resources required to view the image in a geographical computer environment.

      ColormapDateTime=2/19/2008 9:51:19 PM

    3. Geolocating - Map Registration

      The registration and georeferencing metadata accompanying the online maps will give a very good indication as to map accuracy. A basic assumption of the system is that the survey was done well by the mining company or engineer. Accuracy is totally dependent on this survey. The following items should be considered:

      1. Map Coordinate System

        If the map image contains geographic (lat-long) positions and either annotated coordinate system graticules or annotated control points, then the discreet points and their respective coordinates are used to register the map. Coordinate systems that coincide with known standard coordinate systems (UTM or State Plane) are directly converted to the KY1Z system and those that are considered as local systems are shifted to KY1Z values using positions annotated with their respective latitude and longitude values. The resulting georeferenced map will preserve the mapping scale as realized on the source paper map; however, the accuracy of its positioning within the KY1Z State Plane Coordinate Sysytem (SPCS) will not exceed the National Mapping Accuracy Standards (NMAS) for the USGS 1:24,000 Topographic Quadrangle maps as achieved by the Kentucky Raster Graphic (KRG) dataset. The metadata will contain one of the following three sections and indicates the maps original coordinate sytem prior to transformation to the NAD83 Kentucky Single Zone SPCS (KY1Z):

        1. Metadata for Known Map Projection Grids (SPC, UTM, or Georeferenced Company Grids):

          RegistrationDateTime=2/20/2008 12:49:40 PM

        2. Metadata for Local System

          RegistrationDateTime=12/22/2004 2:36:35PM

        3. Metadata for Geographic (Latitude - Longitude) Positioning

          RegistrationDateTime=10/16/2006 8:50:47 AM
          MapLatitudeNorth=37° 18' 11.5" (37.30319444°)
          MapLongitudeWest=82° 28' 34.0" (82.47611111°)

      2. Image to Map Coordinate System Registration Table

        Review the last column labeled Residual (ft). This reflects the error in feet that points selected on the raw image during the registration process may deviate from the mine grid. The lower the number, the better the accuracy. The RMSE is a statistically weighted average of the individual sample errors.

        If the metadata does not have this table, the map does not have a local grid and you have a map image in which the scaling relative to the original survey may be suspect.

        Image -> Map Coordinate System Registration Table
        Image_X Image_Y Map Map KY1Z-Ft KY1Z-Ft Residual
        Point pixel pixel Northing Easting Northing Easting (ft)
        1 6279 3651 371000.0 2867000.0 3652080.1 5788265.0 1.0
        2 4283 3651 371000.0 2865000.0 3652079.3 5786265.0 0.4
        3 2291 645 374000.0 2863000.0 3655078.5 5784263.8 0.7
        4 5285 644 374000.0 2866000.0 3655079.8 5787263.8 1.4
        5 3287 2649 372000.0 2864000.0 3653078.9 5785264.6 0.3
        6 6277 2652 372000.0 2867000.0 3653080.1 5788264.6 2.6
        7 5281 3651 371000.0 2866000.0 3652079.7 5787265.0 0.8
        RMSE 1.2
        Registered Image (u,v) -> KY1Z (x,y) affine transform:
        x = Ux * u + Uy * v + Tx
        y = Vx * u + Vy * v + Ty
        Ux = 1.00250829
        Vx = 0.00060275
        Uy = 0.00144282
        Vy = -0.99788572
        Tx = 5781965.73326712
        Ty = 3655720.49915608
      3. Registration KRG Adjustment


        When this value is present and set to True it indicates that the basis of map geopositioning is not supported by a georeferenced coordinate system such as a standard map projection (SPC or UTM) or a local (company) control grid that has been georeferenced. In these cases the map image was geopositioned by relating features appearing on the map to commensurate features appearing either on the Kentucky Raster Graphic (KRG) dataset or other digital imaging products such as the scanned Geologic Quadrangles (GQ), Kentucky Digital Ortho Quads (DOQQ), Farm Service Agency NAIP (FSA/NAIP) photoimagery, etc.

        The RegistrationKRGAdjustmentType parameter indicates how the map image was related to various georeferenced digital map products. This parameter has the following three possibilities:

        1. LinkTableWithMapGridOrScaleHeldRigid

          Several features appearing on the map were correlated to commensurate features appearing on various georeferenced digital map products, however, the map scale as determined by a previous registration operation was held static and the resulting statistical transformation only includes translation (shifting) and rotation components.

          When this option is used it will be accompanied by a registration table indicating how well the features were registered.

        2. LinkTableWithFitToTopographicFeature

          Several features appearing on the map were correlated to commensurate features appearing on various georeferenced digital map products and the map image was fully transformed (translated, scaled, and rotated) based on that particular feature registration.

          When this option is used it will be accompanied by a registration table indicating how well the features were registered.

        3. NoLinkTableMapGridOrScaleHeldRigid

          The map was manually shifted and rotated, but not re-scaled, so that features appearing on both the map and various georeferenced digital products visually aligned as best as possible. This method is similar to the LinkTableWithMapGridOrScaleHeldRigid method, however, it is based on a manual/visual technique that is not statistically sampled.

    Quality Control

    RegistrationCheckDateTime=2/20/2008 1:49:36 PM

    Rectified World File:

    Georectified Image (u,v) -> KY1Z (x,y) world file affine transform.
    Ux = 1.00000
    Vx = 0.00000
    Uy = 0.00000
    Vy = -1.00000
    Tx = 5781965.50000
    Ty = 3655724.50000

  3. Summary of Map Image Properties

    1. Image Properties

      RectifiedDateTime=2/20/2008 10:17:59 PM

    2. Map Envelope

      LowerLeftCoordinates: x=5781965.00 y=3651760.00
      UpperLeftCoordinates: x=5781965.00 y=3655725.00
      UpperRightCoordinates: x=5789109.00 y=3655725.00
      LowerRightCoordinates: x=5789109.00 y=3651760.00
      LowerLeftCoordinates: ddLat=37.314536N ddLong=82.789802W
      UpperLeftCoordinates: ddLat=37.325420N ddLong=82.789369W
      UpperRightCoordinates: ddLat=37.324795N ddLong=82.764813W
      LowerRightCoordinates: ddLat=37.313911N ddLong=82.765249W

    3. Final Quality Control/Quality Assurance Check

      RectificationCheckDateTime=21-Feb-08 08:54:57