Raster Color Composite (RCC) Images of United States Geological Survey (USGS) Topographic Quadrangles in As-Delivered Coordinate System and Datum

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Frequently-anticipated questions:


What does this data set describe?

Title:
Raster Color Composite (RCC) Images of United States Geological Survey (USGS) Topographic Quadrangles in As-Delivered Coordinate System and Datum
Abstract:
NOTICE: THIS IS NOT an official USGS metadata file for RCCs. This is an ISGS metadata entry for cataloging purposes. You are encouraged to consult the original USGS metadata file.

This metadata file applies to the overall collection. The individual RCCs are accompanied by their original USGS metadata.

This is a file collection of USGS Raster Color Composite (RCC) GeoTIFF images. They are georeferenced images of USGS topographic maps, from the DRG (digital raster graphic) family of USGS products, essentially the same as DRGs but at a higher resolution. See the supplemental information section for more about RCCs.

Resolution is 500 and 1000 dots per inch (dpi). The spatial reference is UTM zone 15 or 16, NAD 1927 or 1983, as appropriate to the individual map images. The collection includes about 75 7.5-minute quadrangles in Illinois that have been obtained for recent geologic mapping efforts.

The majority of the files show the entire topotraphic map. Some, however, show only the text layer. The majority are archived "as delivered", but a handful have been subsequently processed to add a blue fill for water bodies.

Any combination of "as delivered" files with the following extensions may accompany the RCC GeoTIFFs: .dat - a list of parameters about the image, .fgd - the USGS metadata file, .tfw - the TIFF world file. The image files also have related ESRI ArcGIS files such as .rrd and .aux.

Naming convention: The files are named according to the traditional USGS quadrangle convention, e.g. 37088d8.tif. Files with 1000 dpi resolution have "1000" appended to the file name, e.g. 37088d8_1000.tif. Files that have an added color fill for water bodies have the letter "f" appended to the file name, e.g. 37088d8f.tif.

Note that the bounding coordinates reported below are for the entire state of Illinois, not for any single quadrangle.

Supplemental_Information:
The following documentation was reproduced from a file called documentation.txt on one of the delivery CDs. The RCC is a composite of the separates. It appears that in this discussion the terms DRG and RCC are used interchangably.

rcc = Raster Color Composite. DRGs at 500 and 1000 dpi. rcs = Raster Color Separate. With collar information removed rfs = Raster Feature Separate. Conform to a draft archive standard.

Traditional analog feature separates

The original materials for a USGS 7.5-minute quadrangle are various types of mylar negatives. Most of these materials are scribecoats -- mylar sheets coated with a thin layer of wax. During original map compilation the wax was scraped off with precision scribing instruments, producing what is essentially a hand-crafted negative.

The organization of these materials was driven first by the 7.5-minute format of the maps, and second by the color characteristics of the quadrangles. Traditional USGS maps are printed with five colors of ink (black, red, brown, green, blue). The white paper makes a sixth color, and purple was added in the 1960s as a seventh. Six additional colors are typically simulated with lithographic screens.

All the features on one feature separate are of the same color, but not all features of the same color are on one separate. Over the years conventions and production guidelines were developed for what features should be grouped together on a separate, but these relationships were never formally standardized. The average quadrangle has about eight feature separates, but it is not unusual for there to be as many as 20.

The mylar separates are saved in USGS archives for every topographic quadrangle. Although the mylar is fairly durable, it does not last forever. As quads are reprinted and revised, the mylar sheets are refreshed by photographic copying. Unfortunately, each generation of copying degrades the image quality slightly. Some layers of some quadrangles are on their sixth or seventh generation, with visible deterioration in the linework.

Digital feature separates

Starting in the early 1990's, digital drafting tools began to replace scribing in map revision. A map revision typically begins with scanning the feature separates of the old map. The resulting digital separates are updated in computer aided drafting (CAD) environments. The primary outputs of the revision are digital feature separates that can be combined to make press negatives to print a new map, or a digital composite that can be used to make a digital raster graphic (DRG).

The USGS has always sold copies of the mylar feature separates, and there is now a growing demand for digital feature separates. Even if this were not true, there is still a need to standardize the format, packaging, and archive methods of digital feature separates to ensure that data produced today can still be found and read the next time they are needed.

DRG characteristics

The DRG images were made by combining the RFS files. They are standard USGS DRGs, except that (1) the scan resolution is 1000 dpi instead of 500 dpi and (2) no FGDC metadata files are present.

RFS characteristics

The RFS images will display as black-and-white positives. The physical file format is very close to that of DRGs. The images conform to TIFF 6.0 and GeoTIFF 1.0. They are 8-bit palette color images with PackBits compression. Most of the same TIFF tags and GeoTIFF keys that are populated for DRGs are also populated for these RFS.

Image quality

The image quality of a RFS is always better than that of a DRG made by scanning a paper map. Scanning mylar materials at 1000 dpi always produces a sharper image than scanning paper at any resolution. Nevertheless, there will still be significant variation in the quality of RFS, depending on the condition of the source materials.

  1. How should this data set be cited?

    United States Geological Survey, 2007, Raster Color Composite (RCC) Images of United States Geological Survey (USGS) Topographic Quadrangles in As-Delivered Coordinate System and Datum:.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.625
    East_Bounding_Coordinate: -87.375
    North_Bounding_Coordinate: 42.625
    South_Bounding_Coordinate: 36.875

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1957
    Ending_Date: 2000
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: digital raster data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions varies x varies, type Pixel

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 15 or 16 as appropriate
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -93.0 or -87.0 as appropriate
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000 meters
      False_Northing: 0.0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest varies
      Ordinates (y-coordinates) are specified to the nearest varies
      Planar coordinates are specified in meters

      The horizontal datum used is NAD27 or NAD83 as appropriate.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    This information applies to DRGs and is assumed to apply to RCCs as well.

    Each raster entity or pixel contains a color index from 0 through 12 referencing a color palette of RGB values from 0 through 255 in which the standard colors used in the DRG are defined.

                         USGS DRG Color Palette
    
          Digital Number    Color       Red      Green    Blue
    
                0           Black       0        0        0
                1           White       255      255      255
                2           Blue        0        151      164
                3           Red         203      0        23
                4           Brown       131      66       37
                5           Green       201      234      157
                6           Purple      137      51       128
                7           Yellow      255      234      0
                8        Light Blue     167      226      226
                9        Light Red      255      184      184
                10       Light Purple   218      179      214
                11       Light Grey     209      209      209
                12       Light Brown    207      164      142
    
    


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Contact_Instructions: Please refer to the Distribution Information section.


Why was the data set created?

These data are appropriate for use in local and regional thematic analysis. The data are not appropriate as a geodetic, legal or engineering base. The data set can serve as an important base cartographic element for many types of maps. The data set was not and is not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS as a reference base layer for maps, the data set has no legal basis in the definition of boundaries or property lines.


How was the data set created?

  1. From what previous works were the data drawn?

    none (source 1 of 1)
    United States Geological Survey, varies, 7.5-minute Raster Color Composites: United States Geological Survey.

    Type_of_Source_Media: digital file
    Source_Scale_Denominator: 24000
    Source_Contribution: map image, or in some cases, text layer only

  2. How were the data generated, processed, and modified?

    Date: 17-Oct-2007 (process 1 of 2)
    The data were received from on CD from the USGS and loaded into the GISDB file repository.

    Some files were named with a "g" or "geo" at the end of the file name. The meaning of these designations is unknown and they were removed from the file name. If there were duplicate files for a given quad only the file with the most recent date was retained.

    Two files had undefined projections (o38089f8_1000.tif and o37089g5_1000.tif.) The projections were defined to be that shown on the map image.

    Raster pyramids (.rrd) were added in ArcCatalog with the Batch Build Pyramids tool. This also added the .aux files.

    Person who carried out this activity:

    Date: 09-Jun-2008 (process 2 of 2)
    New data received on CD from the USGS were loaded into the GISDB file repository for 24K quads Aurora South, Brussels, Gorham, Herod, Highland Park, New Athens East, Nutwood, and Winfield.

    Some files were named with "geo" at the end of the file name. The meaning of this designation is unknown and it was removed from the file name.

    Raster pyramids (.rrd) and .aux files were added using ArcCatalog.

    Person who carried out this activity:

  3. What similar or related data should the user be aware of?

    , ISGS Terms of Use.

    Online Links:

    , University of Illinois Web Privacy Notice.

    Online Links:

    , University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).

    Online Links:

    , Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    none, see USGS metadata

  2. How accurate are the geographic locations?

    none, see USGS metadata

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    The collection includes about 75 7.5-minute quadrangles in Illinois. The USGS metadata may have more information.

  5. How consistent are the relationships among the observations, including topology?

    none, see USGS metadata


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints:
ISGS information must be obtained directly from the ISGS or from an authorized distributor. Be aware that ISGS information obtained from an unauthorized third party may have been altered subsequent to original distribution, or may no longer be current.

Any access to these data, Web sites, computer systems, electronic services, and electronic networks is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice.

Links to these are provided in the Cross References section.

Use_Constraints:
ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved.  University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is provided in the Cross References section.

Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, isgs@isgs.illinois.edu. License fees and a license agreement may be required, depending on the proposed usage.

Any use of these data is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section.

Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data.  Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.

The data do not replace the need for detailed site-specific studies.

  1. Who distributes the data set? (Distributor 1 of 1)

    Information Office, Illinois State Geological Survey (ISGS), a division of the Institute of Natural Resource Sustainability (INRS) of the University of Illinois
    615 East Peabody Drive
    Champaign, Illinois 61820
    USA

    217-333-4747 (voice)
    isgs@isgs.illinois.edu

    Hours_of_Service: 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time
  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    Refer to the Legal Notices of Terms and Conditions of the University of Illinois Web Privacy Policy (there is a link in the Cross References section) for policy statements regarding the following:

    Disclaimer of Liability Disclaimer of Warranties and Accuracy of Data Disclaimer of Endorsement Disclaimer for External Links Disclaimer of Duty to Continue Provision of Data Security Choice of Law

    By obtaining these data you agree to the provisions of the University of Illinois Web Privacy Policy, regardless of the manner in which the information was obtained.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, ESRI formats can be imported into many different GIS software packages. It is expected that customers who obtain these data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.


Who wrote the metadata?

Dates:
Last modified: 24-Feb-2009
Metadata author:

Contact_Instructions: Please refer to the Distribution Information section.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Illinois Natural Resources Geospatial Data Clearinghouse

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