LiDAR Elevation, Duluth Area, Minnesota, 2012

This page last updated: 03/03/2014
Metadata created using Minnesota Geographic Metadata Guidelines


Go to Section:
1. Overview
2. Data Quality
3. Data Organization
4. Coordinate System
5. Attributes
6. Distribution - Get Data
7. Metadata Reference

Section 1 Overview
Originator Minnesota Department of Natural Resources (DNR)
Title LiDAR Elevation, Duluth Area, Minnesota, 2012
Abstract The project vendor, Woolpert, Inc., acquired highly accurate Light Detection and Ranging (LiDAR) elevation data for the Duluth area during the Fall of 2012. LiDAR data are in the UTM Zone 15 coordinate system, NAD83 96, NAVD88 Geoid09 meters tiled by USGS 1/16, 1:24,000 quadrangles.

The vendor delivered the data to the Minnesota Department of Natural Resources (DNR) in several formats:

1) One-meter digital elevation model
2) Edge-of-water breaklines
3) Classified LAS formatted point cloud data

DNR staff created four additional products: two-foot contours, building outlines, hillshades and a difference grid between this data and LiDAR data collected in 2011.

Note: This metadata record was created at the Minnesota Geospatial Information Office by combining information supplied by Woolpert and DNR.
Purpose The data was collected to help assess landscape changes resulting from significant flooding in the Duluth area during Spring 2012.

It is part of the Minnesota Elevation Mapping Project which was initiated to support the development of high accuracy land surface information for the purposes of improving water quality, flood emergency preparedness and response, floodplain mapping, transportation planning and design, recreational planning and design, urban planning and to provide more efficient and effective project planning and execution. This project was funded by the Clean Water Fund of the Clean Water, Land and Legacy Amendment.

For more about the project, see: www.mngeo.state.mn.us/committee/elevation/mn_elev_mapping.html
Time Period of Content Date 2012
Currentness Reference October 29-31; November 2 and 8, 2012
Progress Complete
Maintenance and Update Frequency As needed
Spatial Extent of Data Duluth area, Minnesota, including portions of Aitkin, Carlton, Lake, Pine and St. Louis counties. For exact area covered, see the tile index map at ftp://ftp.lmic.state.mn.us/pub/data/elevation/lidar/projects/duluth_fall_2012/tile_index_map.pdf
Bounding Coordinates -93.159909
-91.551944
47.441972
46.334511
Place Keywords Minnesota, MN, Duluth, Lake, St. Louis, Aitkin, Carlton, Pine
Theme Keywords elevation, LiDAR, DEM, digital elevation model, contour, topographic, topo, DTM, LAS, breakline
Theme Keyword Thesaurus ISO 19115 Topic Category
Access Constraints All data is in the public domain and there are no access constraints.
Use Constraints See Disclaimer field for complete use conditions.
Contact Person Information Tim Loesch, GIS Section Manager
Minnesota Department of Natural Resources
500 Lafayette Rd
St. Paul, MN  55155-4011
Phone: 651-259-5475
Email: tim.loesch@state.mn.us
Browse Graphic None available
Associated Data Sets LiDAR data flown over this area in 2011 ( http://www.mngeo.state.mn.us/chouse/metadata/lidar_arrowhead2011.html ) is stored in this folder: ftp.lmic.state.mn.us/pub/data/elevation/lidar/q250k/ Check the q250k_tile_index.pdf map ( ftp.lmic.state.mn.us/pub/data/elevation/lidar/q250k/q250k_tile_index.pdf ) to find the name of the subfolder(s) covering your area of interest, then look within those for the folder named "previous".

For more information about elevation data for Minnesota, see: www.mngeo.state.mn.us/chouse/elevation/index.html

Section 2 Data Quality
Attribute Accuracy
Logical Consistency All formatted data are validated using commercial GIS software to ensure proper formatting and loading prior to delivery. The LIDAR data is visually inspected for completeness to ensure that are no gaps between flight lines.
Completeness The dataset is complete
Horizontal Positional Accuracy Horizontal datum: NAD83 96

Compiled to meet +/- 3.8ft horizontal accuracy at 95 percent confidence level.

There are alignment issues when this data is compared to the 2011 (pre-2012 flood) LiDAR data collected from the same area. Issues with the difference grid are being investigated. Notes on the issue can be found at: www.mngeo.state.mn.us/committee/elevation/research_education/DEC-RE_notes_2013-09-03.pdf
Vertical Positional Accuracy Vertical datum: NAVD88 (Geoid09)

1. Report from Woolpert: The LiDAR data vertical accuracy RMSE is 3.6 cm (0.12 ft). The data collected under this Task Order meets the National Standard for Spatial Database Accuracy (NSSDA) accuracy standards. The NSSDA standards specify that vertical accuracy be reported at the 95 percent confidence level for data tested by an independent source of higher accuracy. ( www.fgdc.gov/standards/projects/FGDC-standards-projects/accuracy/part3/ ). Tested 7.1cm (0.23ft) fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using (RMSEz) x 1.96000 Tested against the TIN using independent check points.

2. Report from DNR: The LiDAR collected for this task order was tested using independent, locally provided validation points to meet a vertical accuracy of less than 15cm (0.49 foot) RMSEz The detailed report is here: ftp.lmic.state.mn.us/pub/data/elevation/lidar/projects/duluth_fall_2012/duluth_2012_vertical_validation_report.pdf
Lineage Vendor Processing Steps:

Using Light Detection And Ranging (LiDAR) systems, 154 flight lines of high density data, at a nominal pulse spacing (NPS) of 1.5 meter, were collected over Minnesota counties of Lake, St Louis, Aitkin, Carlton, and Pine (approximately 3,078 sq. miles), along with a 100 meter buffer beyond the project tile boundary. Multiple returns were recorded for each laser pulse along with an intensity value for each return. A total of eleven (11) missions were flown from October 29, 2012 through November 08, 2012. A minimum of three (3) airborne global positioning system (GPS) base stations were used in support of the LiDAR data acquisition. All data for this task order is referenced to UTM 15N, NAD83 96, NAVD88, in meters. Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line. The coverage was classified to extract a bare earth digital elevation model (DEM) and separate last returns. In addition to the LAS deliverables, one layer of coverage was delivered in the ArcGrid binary format: bare-earth.

System Parameters for 1.5 NPS:

Airborne Laser Scanner - ALS70 Specifications
Post Spacing (Minimum): 4.92 ft / 1.5 m
AGL (Above Ground Level) average flying height: 7,799 ft / 2,377.1 m
MSL (Mean Sea Level) average flying height: 8,392 ft / 2,557.9m
Average Ground Speed: 150 knots / 172.6 mph
Field of View (full): 40 degrees
Pulse Rate: 115 kHz
Scan Rate: 25 Hz
Side Lap (Minimum): 25%

Optech Airborne Laster Terrain Mapper (ALTM) Gemini Specifications
Post Spacing (Minimum): 4.92 ft / 1.5 m
AGL (Above Ground Level) average flying height: 6,800 ft / 2,072.6 m
MSL (Mean Sea Level) average flying height: 7,400 ft / 2255.5 m
Average Ground Speed: 150 knots / 172.6 mph
Field of View (full): 40 degrees
Pulse Rate: 100 kHz
Scan Rate: 29 Hz Side

Breaklines defining lakes, greater than two acres, and double-line streams, wider than 30.5 meters (100 feet), were compiled using digital photogrammetric techniques as part of the hydrographic flattening process and provided as ESRI Polygon Z shape files. Breaklines defining water bodies and streams were compiled for this task order. The breaklines were used to perform the hydrologic flattening of water bodies, and gradient hydrologic flattening of double line streams. Lakes, islands, reservoirs and ponds, at a nominal minimum size of two (2) acres or greater, were compiled as closed polygons. The closed water bodies were collected at a constant elevation. Rivers and streams, at a nominal minimum width of 30.5 meters (100 feet), were compiled in the direction of flow with both sides of the stream maintaining an equal gradient elevation.

For more information on these steps, see Woolpert's project report: ftp.lmic.state.mn.us/pub/data/elevation/lidar/projects/duluth_fall_2012/project_report/LiDAR%20Report_DuluthFloodArea.pdf


Additional Products Generated by Minnesota DNR staff:

These products are in the geodatabase for each of the tiles:

1. Two-foot contours were created by resampling the 1-meter DEM to 3 meters, then smoothing the 3-meter grid using a neighborhood average routine, and then creating contours from this surface using standard ArcGIS processing tools.

2. Building outlines were created by extracting from the LAS files those points with Classification 6 (buildings), then grouping those points within 3 meters of each other into a single cluster and then creating an outline around those points. This was done using standard ArcMap tools.

3. Hillshades were created from the one- and three-meter DEMs using standard ArcMap tools. Azimuth value = 215, Altitude = 45, Z-Factor = 1

4. A difference grid between this dataset and LiDAR data collected in 2011 ( www.mngeo.state.mn.us/chouse/metadata/lidar_arrowhead2011.html )

Section 3 Spatial Data Organization (not used in this metadata)

Section 4 Coordinate System
Horizontal Coordinate Scheme Universal Transverse Mercator
UTM Zone Number 15
Horizontal Datum NAD83
Horizontal Units meters

Section 5 Attributes
Overview 1. LAS data were classified using the following standard ASPRS categories:
0 - Unclassified
1 - Unknown
2 - Bare Earth
3 - Low Vegetation (less than 1.1 meters)
4 - Medium Vegetation (1.11 - 2.4 meters)
5 - High Vegetation (2.41 - 200m)
6 - Buildings
7 - Noise
8 - Model Keypoint
9 - Water
14 - Bridge Decks
17 - Overlap

2. Contours
Elevation: Integer value of elevation at contour
Contour_type:
- Index (10-foot contours)
- Index Depression
- Intermediate
- Depression

3. Edge of Water Breakline Types
- Island: Island in a lake feature greater than 2 acres
- Island Stream: Island in a stream feature greater than 2 acres
- Lake: Lake feature greater than 2 acres
- Stream: Riverine feature greater than 100 feet wide
Detailed Citation
Table Detail:

Section 6 Distribution
Publisher Minnesota Geospatial Information Office (MnGeo)
Publication Date
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Email: gisinfo.mngeo@state.mn.us
Distributor's Data Set Identifier Duluth area LiDAR 2012
Distribution Liability 1. Woolpert prepared the original data as set forth in the Scope of Services, in accordance with reasonable care and due diligence as set forth in this Agreement, however, due to the easily alterable nature of electronic media, files, documents, and other deliverables, Woolpert, Inc. makes no warranties, either expressed or implied, with respect to the accuracy, completeness, merchantability, or fitness for any particular purpose, including, but not limited to, use of any/all data as described within this metadata file, by any user of this data. Any use will be at the end-user's sole risk.

2. The Minnesota Department of Natural Resources General Geographic Data License Agreement is online: www.dnr.state.mn.us/sitetools/data_software_license.html

3. MnGeo's data disclaimer is online: www.mngeo.state.mn.us/chouse/disclaimer.html
Ordering Instructions 1. Download this LiDAR data from MnGeo's FTP site using any of these three options:

a. Click on the link under the "Online Linkage" section below which goes to a project folder.

b. Go to a folder which divides the data by 1:250,000 quadrangle boundaries:
ftp.lmic.state.mn.us/pub/data/elevation/lidar/q250k/
Use the tile index to find the folder(s) that cover your area of interest: ftp.lmic.state.mn.us/pub/data/elevation/lidar/q250k/q250k_tile_index.pdf

c. Go to the county folder area: ftp.lmic.state.mn.us/pub/data/elevation/lidar/county/
Choose the folder for your county of interest. NOTE: The county geodatabase mosaic has NOT been updated to include this 2012 data. The geodatabase and las format tiles, however, are the 2012 data.

2. View or download the data via MnTOPO, a mapping website:
www.dnr.state.mn.us/gis/mntopo/index.html

3. View the hillshade layer via a web mapping service (WMS), described here:
www.mngeo.state.mn.us/chouse/metadata/lidar_hillshade_mn.html

For more help with Minnesota's LiDAR data, see www.mngeo.state.mn.us/chouse/elevation/lidar.html
Online Linkage I AGREE to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process or link to download information. See "Ordering Instructions" above for details.

Section 7 Metadata Reference
Metadata Date 03/03/2014
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Email: gisinfo.mngeo@state.mn.us
Metadata Standard Name Minnesota Geographic Metadata Guidelines
Metadata Standard Version 1.2
Metadata Standard Online Linkage http://www.mngeo.state.mn.us/committee/standards/mgmg/metadata.htm


This page last updated: 03/03/2014
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