|Title||LiDAR Elevation, Minnesota River Basin, Southwest Minnesota, 2010|
|Abstract||AeroMetric acquired highly accurate Light Detection and Ranging (LiDAR) elevation data for the Minnesota portion of the Minnesota River Basin. The project area of approximately 17,260 square miles covered the following 25 Minnesota counties: Brown, Chippewa, Cottonwood, Douglas, Faribault, Jackson, Kandiyohi, Lac qui Parle, Le Sueur, Lincoln, Lyon, Martin, Murray, Nicollet, Nobles, Pipestone, Pope, Redwood, Renville, Rock, Sibley, Swift, Waseca, Watonwan, and Yellow Medicine.
LiDAR data acquisition, control and QC surveys were completed during the spring and fall leaf-off periods: April 8 - May 5 and November 2 - 19, 2010. The tiling scheme is 16th USGS 1:24,000 quadrangle tiles. Aerometric delivered the data to the Minnesota Department of Natural Resources (DNR) in several formats: LAS, geodatabase, DEM and breaklines.
DNR staff created two additional products: two-foot contours and building outlines.
Note: This metadata record was created at the Minnesota Geospatial Information Office by combining information supplied by AeroMetric and DNR.
|Purpose||The data was collected as part of the Minnesota Elevation Mapping Project, managed by the Minnesota Department of Natural Resources: www.mngeo.state.mn.us/committee/elevation/mn_elev_mapping.html|
|Time Period of Content Date||2010|
|Currentness Reference||LiDAR data was collected during spring and fall leaf-off periods: April 8 - May 5 and November 2 - 19, 2010.|
|Maintenance and Update Frequency||Unknown|
|Spatial Extent of Data||25 counties in the Minnesota River Basin in southwest Minnesota (see Place Keywords)|
|Place Keywords||Southwest Minnesota, Minnesota River Basin, Brown, Chippewa, Cottonwood, Douglas, Faribault, Jackson, Kandiyohi, Lac qui Parle, Le Sueur, Lincoln, Lyon, Martin, Murray, Nicollet, Nobles, Pipestone, Pope, Redwood, Renville, Rock, Sibley, Swift, Waseca, Watonwan, Yellow Medicine counties|
|Theme Keywords||elevation, LiDAR, DEM, digital elevation model, contour, topographic, topo, DTM, LAS, breakline|
|Theme Keyword Thesaurus||None|
|Use Constraints||See Disclaimer field for complete use conditions.|
|Contact Person Information||Rob Merry,
4020 Technology Parkway
Sheboygan, WI 53083
|Browse Graphic||None available|
|Associated Data Sets||For more information about elevation data for Minnesota, see: www.mngeo.state.mn.us/chouse/elevation/index.html|
|Section 2||Data Quality|
|Attribute Accuracy||See Vertical Positional Accuracy field.|
|Horizontal Positional Accuracy||All area data products were acquired at or below 1700 meters above mean terrain (AMT) and have a horizontal accuracy of 0.30 meters, with a nominal point spacing of 1.3 meters.|
|Vertical Positional Accuracy||The data was to meet a 15cm Vertical RMSE which was exceeded with values better than 10cm throughout the project.
The Fundamental Vertical Accuracy (FVA) of the Classified Bare Earth for all Areas achieved is 0.07 meters at a 95% confidence level in the 'Open Terrain' land cover category. 502 control points were used in this evaluation.
The accuracy statement is based on the area of moderate to flat terrain. Diminished accuracies are to be expected in areas in dense vegetation. The accuracy of the LiDAR data as tested met the vertical accuracy or better, however, derived products may be less accurate in areas of dense vegetation due to a fewer number of points defining the bare-earth in these areas.
|Lineage||The LiDAR data was captured using multiple fixed wing aircraft equipped with a LiDAR system. Each LiDAR system includes a differential GPS unit and inertial measurement system to provide superior accuracy. A total of 107 flight missions were required to cover the 25 counties. Airborne accuracy was achieved using the State of Minnesota's Department of Transportation CORS network. Smooth best estimated trajectories (sbets) were generated using Applanix's POSPAC 4.4 as well as POS MMS software packages. LAS files were created using Optech's Dashmap, ASDA, and LMS software. Survey checkpoints were collected by AeroMetric to assist with the validation of the LiDAR point cloud. Point cloud classification and deliverables were created with Terrasolid's software suite package as well as ESRI's Arc software.
1. Scanner - Optech Gemini
2. Flight Height - 1700 meters above mean terrain
3. Scan Angle - 40 degrees
4. Sidelap - 50%
5. Nominal Post Spacing - 1.3 meters
6. Scan Frequency - 34 Hz
GPS and IMU processing parameters:
1. Processing programs and version - Applanix - POSGPS and POSProc, versions 4.4, MMS version 5.2
2. Maximum baseline length - Not greater than 60km
3. Number of base stations during LiDAR collection - A minimum of 1
4. Max separation between base stations during LiDAR collection - 0.05m
5. IMU processing monitored for consistency and smoothness - Yes
Point Cloud Processing:
1. Program and version - Optech ASDA, Dashmap
2. Horizontal Datum - NAD83(NSRS2007)
3. Horizontal Coordinates - Universal Transverse Mercator, Zone 15, in meters
4. Vertical Datum - NAVD88
5. Geoid Model used to reduce satellite-derived elevations to orthometric heights - NGS Geoid03
LIDAR Processing by AeroMetric:
1. Processing Programs and versions - TerraSolid TerraScan (version 010.021), TerraModeler (version 010.005 and TerraMatch (version 010.012) and Intergraph MicroStation (version.08.05.02.55).
2. Point Cloud data was imported to TerraScan in a Microstation V8 (V) CAD environment on a specified tiling scheme.
3. Analyze the data for overall completeness and consistency to ensure that there are no voids in the data collection.
4. Inspect for calibration errors in the dataset using the TerraMatch software. This was accomplished by sampling the data collected across all flight lines and classifying the individual lines to ground. The software will use the ground-classified lines to compute corrections (Heading, Pitch, Roll, and Scale).
5. Orientation corrections (i.e. Calibration corrections) were then applied (if needed) to the entire dataset.
6. Automatic ground classification was performed using algorithms with customized parameters to best fit the project area. Several areas of varying relief and planimetric features were inspected to verify the final ground surface.
7. AeroMetric provided Quality Assurance and Quality Control (QA/QC) data for this project. AeroMetric captured QA/QC points in the 'open terrain' land cover category that were used to test the accuracy of the LiDAR ground surface. TerraScan's Output Control Report (OCR) was used to compare the QA/QC data to the LiDAR data. This routine searches the LiDAR dataset by X and Y coordinate, finds the closest LiDAR point and compares the vertical (Z) values to the known data collected in the field. Based on the QA/QC data, a bias adjustment was determined, and the results were applied (if necessary) to the LiDAR data. A final OCR was performed with a resulting RMSE of 0.088m for the project.
8. Once the automatic processing and the testing of LiDAR was complete, AeroMetric meticulously reviewed the generated bare-earth surface data to ensure that proper classification was achieved as part of a Quality Control process.
9. Breaklines were collected for all 25 counties. The criteria for breaklines were rivers that were 100 feet or larger with double lines and ponds that were 2 acres or larger. Breaklines were delivered as an ESRI feature class (PolygonZ format). Each shapefile contains georeference information. Breakline elevations use the same coordinate reference system as the LAS point cloud. Breaklines were delivered in tile format and edgematch seamlessly both vertically and horizontally. The tiling scheme was provided by the Minnesota Department of Natural Resources and is from the USGS 16th 1:24,000 quadrangle tiles.
10. Final deliverables were generated and output to the DNR-specified tiling scheme. Details for each format:
Classified point cloud data was delivered in LAS v1.2. Georeference data is located in the LAS header. Each LiDAR point has a unique timestamp. Data was delivered in tile format without overlap.
An ESRI geodatabase was created on a tile basis for all 25 counties. Each geodatabase has a feature dataset named Terrain Data which contains bare earth points, bridge breaklines, and hydro breaklines (if present). Each geodatabase also has a raster DEM that was generated from the LAS points and the breaklines. The raster DEM tiling scheme was an orthogonal setup based on the original tile scheme. Each geodatabase contains georeference information. The geodatabases use the same coordinate reference system as the LAS point cloud.
Bare Earth Surfaces (raster DEMs) were generated from the classified bare earth ground LiDAR point cloud for every tile of this 25 county project. DEMs were generated using the following criteria: Cell size 1 meter, delivered in ESRI 32-bit floating raster, tiled without overlap. Georeference data was included in the raster file. Depressions (sinks), natural or man-made were not filled as specified by the job specifications. Water bodies (ponds and lakes) and wide streams and rivers were hydro-flattened within the DEMs based on the following criteria: 2-acre water bodies or larger or flowing water nominally wider than 100 feet.
Breaklines were collected for all 25 counties. The criteria for breaklines were rivers that were 100 feet or larger with double lines and ponds that were 2 acres or larger. Breaklines were delivered as an ESRI feature class (PolygonZ format). Each shapefile contains georeference information. Breakline elevations use the same coordinate reference system as the LAS point cloud. Breaklines were delivered in tile format and edge match seamlessly both vertically and horizontally.
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
|Section 3||Spatial Data Organization (not used in this metadata)|
|Section 4||Coordinate System|
|Horizontal Coordinate Scheme||Universal Transverse Mercator|
|UTM Zone Number||15|
|Overview||The classification scheme of the LiDAR point cloud:
1 = unclassified
2 = bare earth ground
4 = vegetation
6 = buildings
7 = noise
8 = model keypoints
9 = water
10 = ignored ground
14 = bridges
|Publisher||Minnesota Department of Natural Resources|
|Contact Person Information||Nancy Rader,
GIS Data Coordinator|
Minnesota Geospatial Information Office
658 Cedar Street
St. Paul, MN 55155
|Distributor's Data Set Identifier||MN River Basin LiDAR 2010|
|Distribution Liability||1. MnGeo's data disclaimer is online: www.mngeo.state.mn.us/chouse/disclaimer.html
2. Minnesota Department of Natural Resources General Geographic Data License Agreement
1) The Minnesota Department of Natural Resources (MNDNR) grans to you a non-exclusive, non-sublicensable, license to use these digital data. This License agreement applies to all digital data acquired from DNR staff, FTP sites, or other internet-based delivery systems. In the event that another license agreement issued by DNR staff is explicitly associated with a particular data set, the terms of the other license agreement prevail, and the terms expressed in this more general license agreement are nullified.
2) The MNDNR makes no representations about the suitability of these data for any purpose. The data are provided 'as is' without express or implied warranties, including warranties of merchantability and fitness for a particular purpose or non-infringement.
3) MNDNR is not obligated to provide updates to these data in the event that newer versions become available. MNDNR provides documentation when available through established distribution mechanisms.
4) The user relieves the MNDNR and its respective officers, agents, and employees of any liability for any and all damages resulting from use of mis-use of these data including, but not limited to:
a. Incidental, consequential, special or indirect damages of any sort, whether arising in tort, contract or otherwise, even if MNDNR has been informed of the possibility of such damages, or
b. For any claim by any other party. Furthermore, in States that do not allow the exclusion of limitation of incidental or consequential damages, you may not use these data.
5) When these data are used in the development of digital or analog(hardcopy) products, MNDNR must be acknowledged as having contributed data to the development of the product.
6) Although the use of these data are not restricted, they may not be sold commercially or privately without the written permission of MNDNR.
|Ordering Instructions||The LiDAR data provided by DNR may be downloaded from MnGeo's FTP site by clicking on the link below.
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|
|Contact Person Information||Nancy Rader,
GIS Data Coordinator|
Minnesota Geospatial Information Office
658 Cedar Street
St. Paul, MN 55155
|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|