This Web site contains information on activities of the National Geologic Map Database Project (NGMDB). The NGMDB is a collaborative effort primarily involving the USGS and the Association of American State Geologists. This Web site contains informal, generally time-sensitive material intended for project members, cooperators, and interested parties.

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How to scan maps and add them to the NGMDB Image Library

Thank you for agreeing to add content to the National Geologic Map Database's Image Library. As our partner in the Database project, you're helping to build this into a National resource, for users of all backgrounds and interests. We ask that you review the instructions in this Help page, and let us know if you have any questions, or any comments on how to improve these pages and the Image Library itself.

Helpful Documents:
      Image Library Overview
      Technical Details

Please note -- at present, only bedrock and surficial geologic maps are being loaded into the Image Library. However, when the Library is well-populated with those maps, we could expand its scope to include other geoscience maps (e.g., of resources or hazards).

For each map that you want to add:

• Step 1 - ensure that the map is already in the NGMDB Map Catalog.
  The Image Library is a subset of the Map Catalog, and uses the bibliographic records in the Catalog to identify which products are appropriate to include in the Image Library. When you are ready to begin, we will send you an Excel file containing all Map Catalog records for bedrock and surficial geologic maps published by your agency. Please use this list as your starting point, to identify the maps you'd like to contribute to the Image Library. Two additional points:
  • if you want to add any maps published by another organization, just let us know and we'll include those records in the Excel file.
  • if you want to add a map that isn't in the Map Catalog, you must first enter the map record into that database. [If you're not familiar with that procedure, please see http://ncgmp.usgs.gov/ngmdbproject/cathelp/ for information, or contact Dave Soller at drsoller@usgs.gov].
  
  
• Step 2 - Scan the map.
  Through discussions with many State geological surveys, we've decided to use the following scanning parameters for maps that we scan. However, if you wish to use other parameters (or have already scanned the map according to different parameters), that's not a problem. We'll work with you, and will certainly try to use the image files that you have created.
  Here are the parameters we use, and what we recommend:
  • Scanner - large format, to minimize the need to tile scans of pieces of a map
  • Resolution - 300 dpi
  • Color - 24 bit
  • File format - Tiff
  • File size - most map images are much less 500MB in size. However, if you scan a large map and the Tiff file exceeds this size, we will not be able to compress it to MrSID format using our Desktop version of the LizardTech compression software. If you create a file larger than 500MB, please let us know, and we'll work out a solution.
  • Miscellaneous settings - these may or may not be useful, as they are specific to our scanner and Wideimage software: set paper size to "auto+3%", and set gamma correction under advances to "+1.5".
  
  
• Step 3 - Edit the map image.
  Map images may need to be edited for orientation and color correction. Here's what we commonly do (in Adobe Photoshop):
  • if the map needs to be rotated to make it more level, we draw a box around it and use the rotate-arbitrary function to get the image as level as possible.
  • to make the map more legible and to increase the whiteness of the background (e.g., to minimize the effects of ageing), we use the autocolor and autocontrast functions. Sometimes we use the brightness/contrast feature if the image is faded or dark, or if we scanned a blueline copy.
  
  
• Step 4 - Name the image file.
  
  • If you already have a naming convention:
    1. enter the image's file name into the Excel file.
    2. if you scan more than 1 sheet of a map, insert a new row in the Excel file, just below the row for that map. Copy the map's unique identifier (the "pub_id") into the new row, and enter the file name and assign the sheet a letter (e.g., sheet "b"). We'll assume that the first sheet is "a", so you don't need to enter it.
  • If you want to use our naming convention:
    1. enter the file name into the Excel file, using this naming convention --
       "q<mapscale>_<pubid><mapsheet>_<publisher>_<editflag>.tif"
       where: "mapscale" is the scale divided by 1000, with anything to the right of the decimal place deleted (e.g., use "24" for a 1:24,000-scale map, "100" for 1:100,000, "62" for 1:62,500, "1000" for 1:1,000,000). We use this scale value to program the size of the thumbnail we need to show, and to help us organize our archive;
       "pubid" is the Map Catalog's unique identifier for that map;
       "mapsheet" is "null" if the map is contained on one sheet, and is "b", "c", etc. if the map product has two or more sheets and you chose to scan them;
       "publisher" is the 2-digit postal-code abbreviation of the geological survey that published the map (e.g,. "nc" for the North Carolina Geological Survey; for the USGS we use "us"; for other publishers we'll need to specify some other abbreviation, such as "gsa" for the Geological Society of America); and
       "editflag" can be left as "null"„it's an optional item that we sometimes use to keep track of an image's edit status ("a" is the raw, scanned image; "b" is the edited image; "c" is the final version of the edited map; and "d" is the final version of the edited map, without the collar information).
       An example is "q100_5881b_us_c.tif".
    2. if you scan more than 1 sheet of a map, insert a new row in the Excel file, just below the row for that map. Copy the map's unique identifier (the "pub_id") into the new row, and enter the file name and assign the sheet a letter (e.g., sheet "b"). We'll assume that the first sheet is "a", so you don't need to enter it.
  
  
• Step 5 - Archive the Tiff image.
  If you would like us to archive the Tiff file alongside the many images we have now archived, we will do this. Or, we welcome you to archive the file at your agency. These files are essential if, in the future we need to compress the file in some other format, or if you need to plot the map (for example, if the map is out of print).
  If you would like us to archive the file, please send it to us on CD or DVD. You may of course send us one disk with many images on it. Also, we can use the files to perform Step 6.
  
  
• Step 6 - Compress the image to MrSID format (OPTIONAL).
  The Image Library relies on LizardTech ExpressView server and MrSID compression to serve manageable bits of the image to the user's Web browser. If you have the compression software, that's great. If not, we can compress your Tiff files - you'll just need to send them to us, on CD or DVD; at your discretion, we will archive the Tiffs or will return the disk to you after we've compressed the images. Here are the compression parameters we use:
  • Compression Ratio - 20:1 for color images, and 10:1 for black and white images that were scanned as 8-bit indexed color (these are the default settings)
  • Format - please use the old, version 2 format, not the new, "G3" format. The previous format seems to work better. We are investigating the use of JPEG2000 format to replace MrSID, and will keep you apprised of any format changes; we will not adopt this new format if it causes problems for you or for the user.
  
  
• Step 7 - Add the image to the Library.
  We offer two ways to participate:
  • We can serve the images from our server, and direct users to you when they request a copy of the paper map or image file. For an example of this arrangement, please see (at http://ngmdb.usgs.gov/ImageLibrary/) the maps of central North Carolina, contributed by the North Carolina Geological Survey. If you would like for your maps to be "view-only", we can disable the "Download this map in MrSID format" function on the map viewer page, and direct users to contact you to inquire about the availability of the map image. If you choose to participate in this way, please do the following:
    1. email the completed Excel file to Rob Wardwell, at rwardwell@usgs.gov
    2. send the CD or DVD containing the Tiff and/or MrSID file to:
       Dave Soller
       U.S. Geological Survey
       12201 Sunrise Valley Drive
       National Center, MS 926-A
       Reston, VA 20192
    When we load the images, and before the images are made available to the public, we will contact you to address any questions or concerns.
  • You can, of course, from your site serve any form of the map you choose. Here's what we can offer you -- from the thumbnail graphic of your map at the Image Library's hit list of maps that occur within the user-specified search area, we will simply link to whatever site you would like (e.g., to your map sales office, or to a server where the user can download a browse graphic, PDF, or TIFF image of the map). If you already serve MrSID images via LizardTech's ExpressView server we can, when a user wants to view your map, link from our pages directly to your MrSID images, if that is what you would prefer. If you choose to participate in any of these ways, please do the following:
    1. add a field to the Excel file, for the URL of the MrSID image on your server
    2. email the Excel file to Rob Wardwell, at rwardwell@usgs.gov
    3. send us a JPEG thumbnail of the image. The thumbnail should be 256 pixels in the largest direction. Please send it to Rob Wardwell, at rwardwell@usgs.gov with instructions on how you would like us to link to your images, map sales office, etc.
  
  

  Thank you for helping to expand the content of the Geologic Map Image Library.
  If you have any questions or problems, please contact Dave Soller (drsoller@usgs.gov.

  
  
  This page is <URL :http://ngmdb.usgs.gov/Info/imlibhelp/>
  Maintained by Dave Soller (drsoller@usgs.gov)
  last update: July 1, 2004