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Originator: Intermap Technologies Inc.
Publication_Date: 20030207
Title: "ikpd4semb"
Edition: 1
Geospatial_Data_Presentation_Form: Digital Elevation Model
Series_Name: Digital Terrain Models
Issue_Identification: Version 1
Publication_Place: Englewood, CO
Publisher: Intermap Technologies Inc.
Online_Linkage: <URL:http://www.globalterrain.com>
Online_Linkage: <URL:http://www.intermaptechnologies.com>
Online_Linkage: <URL:http://www.globalterrain.com/gt.asp#Product Handbook>

This data set is a digital elevation model (DEM). The DEM products are generated using the Intermap STAR-3i airborne interferometric synthetic aperture radar (SAR) system mounted in a LearJet 36A aircraft.

The Modified Digital Terrain Model (MDTM) data files are digital representations of cartographic information in a grid form after the application of Intermap's proprietary system known as TerrainFit™ and a subsequent filtering process. TerrainFit™ removes high frequency variations found in the first reflective surface DEM. This effectively removes elevation posts of features such as manmade structures, isolated trees, etcetera that have a relatively small footprint. Having removed these features the final regular posted DTM is derived through interpolation of the remaining elevation posts. The filtering process is designed to reduce the noise level in the data.

The DTM data for 7.5-minute by 18-minute units correspond to the USGS 1:63,360 scale topographic quadrangle map series for available areas in the United States. Each 7.5-minute by 18-minute DTM is based on 1.25m pixel resolution using the Universal Transverse Mercator (UTM) projection. Each 7.5-minute by 18-minute tile provides full coverage with overlap into adjacent tiles.

The DTMs are used as a fundamental layer of information in Geographic Information Systems (GIS) and Spatial Information Decision Support Systems (DSS). A number of the priority layers of spatial information recognized by the National Spatial Data Infrastructure may be derived from GLOBAL Terrain DEMs, including elevation, hydrography, slope, aspect, and shoreline delineation.

The STAR-3i system employs three principle technologies: X-band Horizontal -Horizontal (HH) polarized SAR, a ring laser-based inertial measurement unit (IMU), and Differential Global Positioning System (DGPS). STAR-3i was developed by the Environmental Research Institute of Michigan (ERIM) under contract to the U.S. Defense Advanced Research Projects Agency (DARPA).

The system is comprised of two X-band radar antennae that collect data simultaneously. The set of acquired data are "interfered" by a digital correlation process to extract terrain height data and geometrically correct radar images. STAR-3i uses post-processed DGPS data, together with precise inertial measurement data, to attain highly accurate positioning control. Precise terrain height and positioning data are enhanced by careful calibration of the baseline separating the two antennae.

The STAR-3i system accuracy has been independently validated by tests conducted by the U.S. Army Topographic Engineering Center, the Institute of Navigation, Stuttgart University and by NASA. A summary of test results are accessible at <URL:http://www.globalterrain.com>.

Beginning_Date: 20020724
Ending_Date: 20020729
The above dates refer to the time of field data acquisition and therefore reflect ground conditions at that time.

Progress: Complete
Maintenance_and_Update_Frequency: Ongoing

West_Bounding_Coordinate: -155.1
East_Bounding_Coordinate: -154.8
North_Bounding_Coordinate: 69.875
South_Bounding_Coordinate: 69.75

Theme_Keyword_Thesaurus: MEL_Scientific-Engineering_Field_Thesaurus
Theme_Keyword: Elevation
Theme_Keyword: Cartography
Theme_Keyword: Geodesy
Theme_Keyword: Geography
Theme_Keyword: Hypsography
Theme_Keyword: Mapping
Theme_Keyword: Photogrammetry
Theme_Keyword: Stereophotogrammetry
Theme_Keyword: Topography
Theme_Keyword: Radar
Theme_Keyword: Interferometric
Theme_Keyword: Remote
Theme_Keyword: Sensing
Theme_Keyword: SAR
Theme_Keyword: DEM
Theme_Keyword: DTM
Theme_Keyword: DSM
Theme_Keyword: ORRI
Theme_Keyword: ORI
Theme_Keyword: STAR-3i
Theme_Keyword: INSAR
Theme_Keyword: IFSAR
Theme_Keyword: IFSARE
Theme_Keyword: GEOSAR
Theme_Keyword: height
Stratum_Keyword_Thesaurus: MEL_Environmental_Domain_Thesaurus
Stratum_Keyword: Terrain
Stratum_Keyword: Earth
Stratum_Keyword: Surface
Stratum_Keyword: Bald
Stratum_Keyword: Ground
Stratum_Keyword: First
Place_Keyword_Thesaurus: None
Place_Keyword: USA
Place_Keyword: Alaska
Place_Keyword: National
Place_Keyword: Petroleum
Place_Keyword: Reserve
Temporal_Keyword_Thesaurus: None
Temporal_Keyword: 2002
Temporal_Keyword: July

Access_Constraints: Purchase
Use_Constraints: None

Contact_Position: Data Archive Manager
Contact_Organization: Intermap Technologies Inc.

Address_Type: mailing address
Address: 400 Inverness Parkway, Suite 330
City: Englewood
State_or_Province: CO
Postal_Code: 80112-5847
Country: USA
Contact_Voice_Telephone: (303) 708-0955
Contact_Facsimile_Telephone: (303) 708-0952
Contact_Electronic_Mail_Address: <mailto:info@globalterrain.com>

Data_Set_Credit: This data was produced by Intermap Technologies Inc.

This data is delivered on interoperable media with metadata, thumbnail images and quality control report. The data set was developed on a Sun ULTRA SPARC 2 computer system running Solaris (UNIX).

Calculation of the digital elevation model is described in the GT Product Handbook User's Guide. <URL:http://www.globalterrain.com/gt.asp#Product Handbook>

Logical_Consistency_Report: <URL:ikpd4secx.pdf>

Coverage maps are provided for each area of acquisition. <URL:http://www.Gtlocator.Net>

This data derived from a DSM of an accuracy of 2.5 meters RMSE or better in areas of unobstructed flat ground. This accuracy is no longer guaranteed due to the filtering procedures.
This data derived from a DSM of an accuracy of 2 meters RMSE or better in areas of unobstructed flat ground. This accuracy is no longer guaranteed due to the filtering procedures.

Process_Date: 20030207
This DEM data product was derived using Intermap Technologies STAR-3i airborne interferometric SAR data acquisition system. The flying height is 30,000 feet Above Sea Level. The primary look direction is West. Areas of missing data are interpolated using continuous curvature spline over non-data areas. The phase unwrapper utilized is ifprocT. Most incidences of non-data areas are due to radar shadow and layover due to steep terrain. Radar shadow is a factor of the local topography. It is often found in mountainous regions and the urban canyons of built-up areas. Occurances of non-data areas within a DEM are dependent on the look direction of the radar. Significant bodies of water are assigned an elevation which corresponds to the shoreline. Areas of null data are assigned the value -32767.

This data was derived from the original DSM through the application of the TerrainFit™ bare earth processing system and the subsequent application of a 3X3 median filter run with four iterations. The intent in processing the DSM this way was to reduce the inherent variability within the DSM so that contours generated at a one meter interval would conform to standard cartographic expectations. This is an artificially smoothed DSM that was derived from data with a horizontal positional accuracy of 2.5m RMSE and a vertical positional accuracy of 2.0m RMSE. These accuracies can no longer be guaranteed given the filtering procedures.


Direct_Spatial_Reference_Method: Raster

Raster_Object_Type: Grid Cell
Row_Count: 3020
Column_Count: 2600

Grid_Coordinate_System_Name: Universal Transverse Mercator
UTM_Zone_Number: 5
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: 153 degrees West
Latitude_of_Projection_Origin: 0
False_Easting: 500000.0 meters
False_Northing: 0.0 meters
Planar_Coordinate_Encoding_Method: coordinate pair
Abscissa_Resolution: 5.0
Ordinate_Resolution: 5.0
Planar_Distance_Units: Meters
Horizontal_Datum_Name: NAD83
Ellipsoid_Name: GRS80
Semi-major_Axis: 6,378,137
Denominator_of_Flattening_Ratio: 298.257222101

Altitude_Datum_Name: NAVD88 - Geoid99
Altitude_Resolution: 0.01 m or better
Altitude_Distance_Units: meter
Altitude_Encoding_Method: Implicit coordinate

Entity_Type_Label: 5 meter posting grid cell
The DEM is a 32 bit IEEE floating point value Big Endian organized in a one-channel binary interleaved file (BIL) on a 7.5-minute by 18.0-minute geographic (lat/long) grid in UTM projection. The origin of the post is center center.
Entity_Type_Definition_Source: <URL:http://www.globalterrain.com/gt.asp#Product Handbook>
Attribute_Label: Elevation value per grid cell.
Attribute_Definition: Height of the geoid, relative to mean sea level.
Attribute_Definition_Source: <URL:http://www.globalterrain.com/gt.asp#Product Handbook>
Range_Domain_Minimum: 31.0
Range_Domain_Maximum: 104.485
Attribute_Units_of_Measure: meters
Attribute_Measurement_Resolution: 0.01 m or better
Project Information
NPRA1 Task Order#: 01010C0010
NPRA2 Task Order#: 01010C0029
Project Area: National Petroleum Reserve Alaska
Intermap Project Number: 02218
Time of Collection
Flight Segment: m356p23s1
Base Stations: Alpine-Deadhorse-Teshekpuk
Flight Direction: 0.3043429
Pass Acquisition Start Time (includes GPS week): 454584.7804
Pass Acquisition Start Time (GPS in HH:MM:SS): 6:16:25
Pass Acquisition Start Time (UTC in HH:MM:SS): 6:16:12
Pass Acquisition End Time (includes GPS week): 455447.5451
Pass Acquisition End Time (GPS in HH:MM:SS): 6:30:48
Pass Acquisition End Time (UTC in HH:MM:SS): 6:30:35
Pass Acquisition Date: 26-Jul-02
Flight Segment: m356p24s3
Base Stations: Alpine-Deadhorse-Teshekpuk
Flight Direction: 180.2979506
Pass Acquisition Start Time (includes GPS week): 456377.6961
Pass Acquisition Start Time (GPS in HH:MM:SS): 6:46:18
Pass Acquisition Start Time (UTC in HH:MM:SS): 6:46:05
Pass Acquisition End Time (includes GPS week): 457275.4693
Pass Acquisition End Time (GPS in HH:MM:SS): 7:01:15
Pass Acquisition End Time (UTC in HH:MM:SS): 7:01:02
Pass Acquisition Date: 26-Jul-02
Intermap Processing AML Version: 1.1.0, 20030108
ISO 9001 Certification No.: A8379
DEM Origin (North West Corner)
UTM_Easting_(meters): 418412.5
UTM_Northing_(meters): 7753767.5
DEM Extents
UTM_Easting_(meters): Min. 418410 Max. 431410
UTM_Northing_(meters): Min. 7738670 Max. 7753770
Entity_and_Attribute_Detail_Citation: <URL:http://www.globalterrain.com/gt.asp#Product Handbook>

Metadata_Date: 20030604
Contact_Position: Data Archive Manager
Contact_Organization: Intermap Technologies Inc.
Address_Type: mailing address
Address: 400 Inverness Parkway, Suite 330
City: Englewood
State_or_Province: CO
Postal_Code: 80112-5847
Country: USA
Contact_Voice_Telephone: (303) 708-0955
Contact_Facsimile_Telephone: (303) 708-0952
Contact_Electronic_Mail_Address: <mailto:info@globalterrain.com>
Metadata_Security_Classification_System: None
Metadata_Security_Classification: None
Metadata_Security_Handling_Description: None

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Generated by mp version 2.8.12 on Mon Oct 25 09:46:12 2004