30 Meter Digital Elevation Model

This page last updated: 04/03/2002
Metadata created using Minnesota Geographic Metadata Guidelines



Metadata Summary

Originator Metropolitan Council
Abstract This dataset is a 30 meter digital elevation model of the seven county Twin Cities metropolitan area. The data represent an elevation surface of the TCMA in a regular grid where each grid cell is a 30 meter by 30 meter square with a single elevation value for each cell given in feet above mean sea level.

Note: When processing this dataset keep in mind that the vertical units for this dataset are feet while the horizontal units are meters.
Browse Graphic View a sample of the data.
Time Period of Content Date 1980
Currentness Reference Base information is as current as the publication of its source USGS quadrangle maps which vary in publication date from 1979 to 1990 and the national wetlands inventory (lake areas only) which was also published in the early 1980s.
Access Constraints None
Use Constraints None
Distributor Organization Metropolitan Council
Ordering Instructions This dataset is distributed on the internet by clicking below after 'Online Linkage'. Doing so will tell your browser to download a 'ZIP' file which will contain the following:

- Grid dataset
- metdata for the dataset (.htm)
- NOTICE.RTF, an important notice about this dataset that can be read by any word processing software.
Distribution Liability NOTICE: The Geographic Information System (GIS) Data to which this notice is attached are made available pursuant to the Minnesota Government Data Practices Act (Minnesota Statutes Chapter 13). THE GIS DATA ARE PROVIDED TO YOU AS IS AND WITHOUT ANY WARRANTY AS TO THEIR PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE. The GIS Data were developed by the Metropolitan Council for its own internal business purposes. The Metropolitan Council does not represent or warrant that the GIS Data or the data documentation are error-free, complete, current, or accurate. You are responsible for any consequences resulting from your use of the GIS Data or your reliance on the GIS Data. You should consult the data documentation for this particular GIS Data to determine the limitations of the GIS Data and the precision with which the GIS Data may depict distance, direction, location, or other geographic features. If you transmit or provide the GIS Data (or any portion of it) to another user, it is recommended that the GIS Data include a copy of this disclaimer and this metadata.
Online Linkage I AGREE to the notice in "Distribution Liability" above. Clicking to agree will begin the download process (See Ordering Instructions above for details.)


Full Metadata

30 Meter Digital Elevation Model

Go to Section:
1. Identification Information
2. Data Quality Information
3. Spatial Data Organization Information
4. Spatial Reference Information
5. Entity and Attribute Information
6. Distribution Information
7. Metadata Reference Information

 
Section 1 Identification Information   Top of page
Originator Metropolitan Council
Title 30 Meter Digital Elevation Model
Abstract This dataset is a 30 meter digital elevation model of the seven county Twin Cities metropolitan area. The data represent an elevation surface of the TCMA in a regular grid where each grid cell is a 30 meter by 30 meter square with a single elevation value for each cell given in feet above mean sea level.

Note: When processing this dataset keep in mind that the vertical units for this dataset are feet while the horizontal units are meters.
Purpose This digital elevation model reflects surface elevation in the Twin Cities metropolitan area and supports various regional and sub-regional scale topographic analysis (e.g. slope, aspect, etc.).
Time Period of Content Date 1980
Currentness Reference Base information is as current as the publication of its source USGS quadrangle maps which vary in publication date from 1979 to 1990 and the national wetlands inventory (lake areas only) which was also published in the early 1980s.
Progress Complete
Maintenance and Update Frequency None planned
Spatial Extent of Data Includes 88 USGS 7.5 minute quadrangles intersecting the minor watersheds intersecting the Twin Cities 7 County Metropolitan Area. This includes the counties of Anoka, Carver, Dakota, Hennepin, Ramsey, Scott and Washington.
Bounding Coordinates -96.912
-92.521
47.526
44.244
Place Keywords Twin Cities, Anoka County, Carver County, Dakota County, Hennepin County, Ramsey County, Scott County, Washington County
Theme Keywords elevation, topography, DEM, digital elevation model
Theme Keyword Thesaurus None
Access Constraints None
Use Constraints None
Contact Person Information Steve Kloiber, Senior Water Resource Planner
Metropolitan Council Environmental Services
390 Robert Street North
St. Paul, Minnesota 55101
Phone: 651-602-1056
FAX: 651-602-1130
E-mail: steve.kloiber@metc.state.mn.us
Browse Graphic View a sample of the data.
Browse Graphic File Description Sample map showing the DEM30Meter layer.
Associated Data Sets 10-foot elevation contours, Topographic Depressions (Sinks), DNR Lakes (Extracted from NWI)

 
Section 2 Data Quality Information Top of full metadata Top of page
Attribute Accuracy This dataset is a grid file with elevation as the only attribute. The accuracy of this attribute is discussed under the topic of vertical position accuracy in this metadata file.
Logical Consistency The data are topologically correct and verified
Completeness The dataset is complete for the 89 USGS 7.5 minute quadrangles.
Horizontal Positional Accuracy Positional accuracy for areas derived from 7.5 minute quads cannot be assumed to exceed National Map Accuracy Standards for 1:24,000 scale maps (+/- 40 feet).
Vertical Positional Accuracy Vertical accuracy for areas derived from 7.5 minute quads cannot be assumed to exceed National Map Accuracy Standards for 1:24,000 scale maps with 10-foot elevation contours (+/- 5 feet).
Lineage The software used to derive the dataset was ANUDEM ( http://cres.anu.edu.au/outputs/software.html) Input data included elevation contours derived from USGS 10-foot DLG contours, topographic depression points, and lake polygons extracted from the National Wetlands Inventory by the Minnesota DNR.

Tile boundaries for the lake data were dissolved prior to processing. Lake surface elevations were calculated as zonal minimums of surface elevations for each lake. The resulting output is in a floating point grid, with units of feet.

The interpolation parameters used in ANUDEM for this process were as follows:

Drainage Enforcement On
Elevation Data Consists Mainly of Contours
Non-Negative RMS Factor = 1.0
Vertical SE = 0.0
Roughness Penalty = 0.0 (Recommended for Contour Data)
Elevation Tolerance 1 = 5.0 feet
Elevation Tolerance 2 = 100.0 feet
Maximum Number of Iterations = 40
Elevation Units = Feet
Elevation Minimum = 660.0 feet
Elevation Maximum = 1230.0 feet
Elevation Centered on Grid Cell Center
Horizontal Position Units = Meters
Grid Spacing = 30.0
X Limit (Minimum) = 410730.0
X Limit (Maximum) = 529740.0
Y Limit (Minimum) = 4913520.0
Y Limit (Maximum) = 5038710.0
Number of Columns in Output Grid = 3967
Number of Rows in Output Grid = 4173
Grid Margin = 20 cells
Number of Input Files = 5
Input File 1 = input_pt.gen (ArcInfo Point Data)
Input File 2 = hyps_upl.gen (ArcInfo Contour Data)
Input File 3 = dem_lake.gen (ArcInfo Lake Boundary Data)
Input File 4 = dem_sink.gen (ArcInfo Sink Point Data)
Input File 5 = union1.gen (ArcInfo Polygon)

NOTE: Drainage enforcement was used, but stream data was not used. The data have not been hydrologically corrected. Using the drainage enforcement option has the effect of filling small spurious sinks that are created as an artifact of the interpolation process. Only sinks that exceed the Elevation Tolerance 1 value (5.0 feet) or sinks that are specifically identified in the topographic depression data file will be retained.
Source Scale Denominator 24000
 
Section 3 Spatial Data Organization Information Top of full metadata Top of page
Native Data Set Environment ArcInfo Version 8x Grid
Geographic Reference for Tabular Data None
Spatial Object Type Raster
Vendor Specific Object Types Integer grid, 30 meter cell size
Tiling Scheme One layer for entire area.
 
Section 4 Spatial Reference Information Top of full metadata Top of page
Horizontal Coordinate Scheme UTM
Ellipsoid GRS80
Horizontal Datum NAD83
Horizontal Units Meters
Distance Resolution 30
Altitude Datum NAVD88
Altitude Units Feet
Depth Datum Not applicable
Cell Width 30
Cell Height 30
UTM Zone Number 15
 
Section 5 Entity and Attribute Information Top of full metadata Top of page
Entity and Attribute Overview
Attributes retain the elevation of the grid cell as derived from the ANUDEM  
processing, described in Lineage.

No value attribute table was created.
Entity and Attribute Detailed Citation None
 
Section 6 Distribution Information Top of full metadata Top of page
Publisher Metropolitan Council
Publication Date Unpublished material
Contact Person Information Mark Kotz
GIS Database Administrator
Metropolitan Council
390 Robert Street North
St. Paul, Minnesota 55101-1805
Phone: 651-602-1644
FAX: 651-602-1674
E-mail: mark.kotz@metc.state.mn.us
Distributor's Data Set Identifier DEM30Meter
Transfer Format Name zipped grid dataset
Transfer Format Version Number ArcInfo: 8x
Transfer Size 38 MB for zip file.
Ordering Instructions This dataset is distributed on the internet by clicking below after 'Online Linkage'. Doing so will tell your browser to download a 'ZIP' file which will contain the following:

- Grid dataset
- metdata for the dataset (.htm)
- NOTICE.RTF, an important notice about this dataset that can be read by any word processing software.
Distribution Liability NOTICE: The Geographic Information System (GIS) Data to which this notice is attached are made available pursuant to the Minnesota Government Data Practices Act (Minnesota Statutes Chapter 13). THE GIS DATA ARE PROVIDED TO YOU AS IS AND WITHOUT ANY WARRANTY AS TO THEIR PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE. The GIS Data were developed by the Metropolitan Council for its own internal business purposes. The Metropolitan Council does not represent or warrant that the GIS Data or the data documentation are error-free, complete, current, or accurate. You are responsible for any consequences resulting from your use of the GIS Data or your reliance on the GIS Data. You should consult the data documentation for this particular GIS Data to determine the limitations of the GIS Data and the precision with which the GIS Data may depict distance, direction, location, or other geographic features. If you transmit or provide the GIS Data (or any portion of it) to another user, it is recommended that the GIS Data include a copy of this disclaimer and this metadata.
Online Linkage I AGREE to the notice in "Distribution Liability" above. Clicking to agree will begin the download process (See Ordering Instructions above for details.)
 
Section 7 Metadata Reference Information Top of full metadata Top of page
Metadata Date 04/03/2002
Contact Person Information Steve Kloiber, Senior Water Resources Planner
Metropolitan Council Environmental Services
390 Robert Street North
St. Paul, Minnesota 55101-1805
Phone: 651-602-1056
FAX: 651-602-1130
E-mail: steve.kloiber@metc.state.mn.us
Metadata Standard Name Minnesota Geographic Metadata Guidelines
Metadata Standard Version 1.2
Metadata Standard Online Linkage http://www.gis.state.mn.us/stds/metadata.htm


This page last updated: 04/03/2002