ARCDBA.Wetland_MD_DNR_Poly

These digital data files are records of wetlands location and classification as defined by the U.S. Fish & Wildlife Service's National Wetlands Inventory (NWI) program. See the Entity_and_Attribute_Information section for a detailed description of NWI's Classification scheme. These wetlands were mapped by Maryland Department of Natural Resources (MD DNR) using Maryland's Digital Orthophoto Quarter Quads. Data are available in 3.75 minute by 3.75 minute blocks and contain wetlands point, line, and area features and attributes. The wetlands were photo interpreted from the photography flown for the Digital Orthophoto Quarter Quads. These were flown over a period from 1988 to 1995. See suplemental information for additional details.File naming convention used for DNR_Wetlands in the ESRI Shape format is as follows:The files names are 8dot3 compliant. In most cases, first five characters of the file correspond to the file names designated by USGS. The Comma-Separated-Value database file, doqqdb.csv, see below for link, lists these five-letter abbreviations (as used by MD DNR) for USGS quadrangle names. Sixth character indicates ordinal_direction of the quadrant, and is as follows:1-NE quadrant; 2-SE quadrant; 3-SW quadrant; 4-NW quadrant.For each quarter quadrant linear features and polygonal features have to exported separately from the native software - MicroImages of Lincoln, Nebraska's TNTMIPS. TNTMIPS uses a proprietary format, known as ".RVC" for vector file structure. Seventh character of the file name indicates whether the file is for a linear (l) or polygonal (p) feature. Both, linear and polygonal files must be displayed together to realize the complete extents of the wetlands present in a given area. Eighth character is always a 6, indicating that the vector is a DNR_Wetland vector. Based on this Beltsville Quad has a total of eight main files - two each for each quadrant. These are as follows:Belts1l6 - Beltsville NE linear;Belts1p6 - Beltsville NE polygon;Belts2l6 - Beltsville SE linear;Belts2p6 - Beltsville SE polygon;Belts3l6 - Beltsville SW linear;Belts3p6 - Beltsville SW polygon;Belts4l6 - Beltsville NW linear;Belts4p6 - Beltsville NW polygon.This is the convention followed for all files.http://dnrweb.dnr.state.md.us/gis/data/index.html This page has a link to DataDownload. Select either 'Wetlands Inventory - DNR (1:12,000, 1988-1995) Data' or 'Digital Orthophoto Quarter Quad (DOQ) - Color Infrared, 1:12,000, 4 meter resolution Data' from the drop down list; on the right side on this download page. Downlaod the wetlands data for any of the counties, or a quarter quad if the DOQ data is selected from the drop down list. This downloads a zip file. This downloaded zip file, along with the wetlands vectors (or the DOQ), contains the Photo Database in a comma separated file, named 'DOQQdb.csv.' This file contians the five character abbreviation and the date of photo flown for creating the Dgital Orthophoto Quarter Quads and the wetlands vectors. Additionally, see the file(s) doqqdb.htm and/or doqqdb.txt for the Photo Database metadata; contained in the downloaded zip file.

The data provide consultants, planners, and resource managers with information on wetland location and type.  The data were collected to augment the efforts of Maryland's regulatory wetland management programs and to assist in resource management efforts such as the Chesapeake Bay Program and the Coastal Zone Management Program.  This data is to be used for guidance purposes only.

Complete
Data update frequency: As needed

Name: Ken Miller

Title: Director, Watershed Information Center

Organization: Maryland Department of Natural Resources

Phone: 410-260-8751

email: NO_SPAM_kenmiller@dnr.state.md.us

Hours of Operation: 0800 - 1700 Eastern Time

Access constraints: See http://www.mncppc.org/html/gismaps.htm#price

Edit Description: Wetland maps are compiled through manual photo interpretation of NAPP and MD DNR specification aerial photography supplemented by Soil Surveys, blue line copies of the National Wetland Invetory Maps along with field checking of wetland photo signatures. Delineated wetland boundary overlays are digitally transferred from interpreted photos and registered to DNR 3.75 minute digital orthophoto maps and then manually labeled. This is done in 'Microstation' software package. These files are then imported into TNTMIPS. The attribution is then done, based on the labels. Files contain ground planimetric coordinates and wetland attributes. The quadrangles were originally referenced to the Maryland State Plane Coordinate System Zone 1900 in the North American Datum of 1983 (NAD83) horizontal datum using the Geodetic Reference System 1980. The scanning process captures the data at a scanning resolution of at least 0.001 inches; the resulting raster data are vectorized, hand fitted by photo interpreters to the digital image and then attributed on an interactive editing station. Quality control steps occur throughout the photo interpretation, map compilation, and map reproduction processes at EarthData International.
Date Updated: 19980330

Edit Description: Additional quality control is done at MD DNR. The data is checked for: 1. Spatial Position, 2. Attribute and label accuracy, 3. Edge Match across neatline and 4. Topological check. 1. Spatial positioning: This is a visual inspection of fit over digital orthophoto quarter quad (DOQQ). Each wetland vector is overlayed on the DOQQ and hundred percent of the linear and polygon features are checked. 2.Attribute and label accuracy: one hudred percent of the linears and polygons must be attributed. The labels are checked against the attributes of the vector and must match the attributes. The attributes must be within a valid set of codes as defined by Cowardian 1987 manual. (Cowardin, L.M., V. Carter, F. Golet, and E. LaRoe. 1979. classification of wetlands and deep water habitats of the United States. U.S. Fish Wildlife Service. 103 pp.) For any given wetland file, this is done by exporting the linear and polygon wetlands attributes database to a text file. This text file is then passed on as a parameter to a batch program ATX.exe obtained from Nontidal Wetlands Inventory office of the U. S. Fish and Wildlife Service. The output of this process is another text file which is evaluated for flagged bad attributes. These are noted and EarthData International is informed of this for fixing. At this point take note of these important URLs. U. S. Fish and Wildlife Service located at the URL http://www.nwi.fws.gov/downloads.htm At this URL pick the link for 'View NWI Map Codes and Definition' which will take you to the URL: http://www.nwi.fws.gov/atx/atx.html Here you can input the wetland classification code in question. The program used to run this is atx.exe. The result of your inquiry would be whether the questionable classification is from a valid NWI codeset. You also have a choice of short, long or none for the description of a valid NWI code; this makes for a good reading and provides for the understanding of wetlands. This also has a link for the code_legend. This lays out a schematic of the hierarchial classification system. Detailed explanation of this system is given in Entity_Definition_Source section of this metadata. 3. Edge Match: All linears and polygons must match across adajcent map sheets. The polygons are closed off at the map boundary/neat line, whereas the linears are not. The current standards for linears is that these stop at about 50 feet from the edge of the neat line. This standard was adopted since 1999. 4. Topological Check: The wetland vectors are checked for overshoots, unclosed polygons, missing or multiple attribution. These are done by queris developed at MD DNR using the query builder of TNT MIPS software. A secondary QC is also performed on a randomly selected number of map sheets in each production batch.. This is done on couple of the quadrangles that were picked to do the primary QC. Additional quarter quads are also selected for this secondary QC. This is still in the .rvc format. The files are delivered and QC done in TNTMIPS .rvc format. The files are then exported to the ESRI Shape file format. A primay and secondary QC is done on these shape files as well. This is to make sure that files have been named correctly and that they are spatially correct. Checks are also done to make sure that the attributes did not get mixed up or left out during the export process. The extents of the vectors are also checked to make sure that a given qurter quad covers the full extent of the quadrangle grid. Any problems found are noted and reported to EarthData International. EarthData International fixes these and sends the files to MD DNR which are checked again for any problems that might have been introduced during the fixes. This quality control is done using TNT MIPS software , and on Arc View version 3.1 and higher.
Date Updated: 20000730

Edit Description: Data are exported from TNTmips format (.RVC) to ESRI shape format for distribution. Shape files are randomly checked to assure the export process completed succesfully. In 2005 it was discovered that most of the linear wetlands data did not work in newer versions of the ESRI Arc software. The problematic files were re-exported using the current version of TNTmips in order to resolve the problem. Anyone who downloaded DNR wetlands prior to November 29, 2005 should obtain a more recent copy of the data for use in newer Arc products.
Date Updated: 20051129

Media: None
Contribution: DNR Wetlands for visual check of fit and attribute accuracy across map sheet

Media: None
Contribution: Blue Line maps of NWI wetlands.

Media: None
Contribution: NAPP Photography 1988- 1989

Media: hardcopyPhoto
Contribution: DNR CIR Photography 1992-1995

Media: None
Contribution: This record is for the Digital Orthophoto Quarter Quads produced based on the 3.75' x 3.75' USGS quadrangles.