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Montana Digitizing Unit Information for Soil Survey Geographic Database Associates

For Major Land Resource Area (MLRA) Soil Survey Offices: There is an Interim Soil Survey Geographic Data Certification letter. This is an interim exhibit until revisions to the National Soil Survey Handbook are completed. The exhibit was revised to better describe the SSURGO product.

For Soil Data Quality Specialists: Our cartographic technicians build surveywide area and special soil features that will have label, internal line, and adjacent soil line join errors coded for easy location through ARC/GIS. Materials sent to soil scientists for author errors will include the raster scans, the soil overlays, and the digital product. Your validating the spatial data to your National Soil Information System database at this point will facilitate workflow for certification.

About Digitizing

About Electronic Map Compilation of published soil surveys: We have the software and expertise to filter rectified imagery and extract raster soil lines for vectorization and labeling. We hope there are no soil scientists who spend their time labeling polygons and smoothing soil lines. We do that very efficiently. We rely on redundant quality control routines to ensure accuracy of the spatial data submitted for digitizing and certification.

About Metadata: The survey information provided in the metadata section of the online form is usually enough for our metadata specialist to complete source citations and process steps for any soil survey sent to us for digitizing/certification. The metadata template issued by the National Cartography and Geospatial Center (NCGC) has had three revisions since the move to surveywide production and elimination of quadrangle based Digital Line Graphs. If metadata is written in your state, please make sure you have the current template.

About Soil Data Warehouse and Soil Data Mart: If your state is involved with soil survey boundary editing, keep in mind that the certifier has to resubmit all the soil surveys affected by any edits of any adjacent survey’s shared boundary for simultaneous upload to the soil data warehouse by state.

Scanner Specifications to Meet SSURGO

Why type of scanner is important: In order to meet scan specifications for SSURGO, a scanner has to capture raster cells horizontally and vertically to match to the source by .01 of an inch. Scanners that meet SSURGO specifications currently cost $50,000. NCGC has two scanners and two or three operators on staff. The scanners are Vidar Surveyor and ANAtech Eagle Color (42160C). Midwest Graphics uses a black and white ANAtech Eagle 4050. If your soil overlays are being scanned anywhere other than at NCGC or Midwest Graphics, be aware of the scanner make and model. Most scanners will have errors around 1/10 inch in one direction (X or Y) depending on scanning orientation of source material. Some vendors may be unaware of the accuracy specifications of the equipment they operate.

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Five Causes of an Unacceptable Raster Scan for SSURGO

  1. If any contact rollers on the scanner are old, dried out, or out of alignment, the overlay can slip as it feeds through and will cause significant warping.
  2. If the scanner has been moved or bumped, scanner cameras should be recalibrated.
  3. If quality control of the output raster files is not consistently practiced, resolution settings can have a major impact on the raster product.
  4. Scanners that do not meet SSURGO specifications. Scanner inaccuracy or operator error can be identified by plotting the raster lines on stable-base and comparing to the compiled soil overlay. Note that most plotters stretch image to some degree.
  5. Bad registration practices on soil overlay during compilation.

Progressive Digitizing for SSURGO

Progressive digitizing and partial certification have produced time gaps between blocks of incoming progressive soils data.

The Montana Digitizing Unit (DU) has reference databases used to create soil survey indices by quadrangle and by adjacent soil survey boundaries. We use these indices to track development processes and as a quick visual aid for status reporting purposes. We would be happy to provide any tracking tool (digital or hard copy) that would facilitate work flow.

Work Flow Sequence Has Changed this Fiscal Year

Before soil scientist compilation edits have been applied to the survey, the MLRA soil survey office (MO) will receive materials for a 10 percent digitizing review at the time the technician has digitally replicated the scan source. The 10 percent review by the MO will therefore be done on data that reflects the scan source, including uncorrected author or inherent survey errors. Typically, plots with scan overlay are sent FedEx overnight. In states where the MO is located, the Montana DU will send the digital surveywide area and special feature layers only.

The soil scientist contact (identified on the survey form submitted to the Montana DU) will receive digital surveywide ARC/GIS product with notation of internal and boundary join label and line errors.

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Barriers to Efficiency and Productivity of Spatial and Soil Business Processes

Lack of or a slow response to author edit requests is our main barrier to efficient processing. Production barriers are delivery postponements and delivery of soil business documentation.

Your Soil Survey

  • Provide your comments regarding the quality and timeliness of your soil survey delivery to the soil data warehouse staging server.
  • How can we better serve your needs while meeting national goals?
  • What story can you share about how digital soils data is being used to help those we serve

Reference Web Sites for Soil Survey Digital Development

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Last Modified: 12/10/2007