BOREAS Elevation Contours over the NSA and SSA in ARC/Info Generate Format
Summary
This data set was prepared by BORIS staff by reformatting the original data into
the ARC/INFO Generate format. The original data were received in SIF at a scale
of 1:50,000. BORIS staff could not find a format document or commercial software
for reading SIF; the BOREAS HYD-08 team provided some C source code that could
read some of the SIF files. The data cover the BOREAS NSA and SSA. The original
data were compiled from information available in the 1970s and 1980s. The data
are available in ARC/Info Generate format files.
Note that the files of this data set on the BOREAS CD-ROMs have been compressed
using the Gzip program. See section 8.2 for details.
Table of Contents
* 1 Data Set Overview
* 2 Investigator(s)
* 3 Theory of Measurements
* 4 Equipment
* 5 Data Acquisition Methods
* 6 Observations
* 7 Data Description
* 8 Data Organization
* 9 Data Manipulations
* 10 Errors
* 11 Notes
* 12 Application of the Data Set
* 13 Future Modifications and Plans
* 14 Software
* 15 Data Access
* 16 Output Products and Availability
* 17 References
* 18 Glossary of Terms
* 19 List of Acronyms
* 20 Document Information
1. Data Set Overview
1.1 Data Set Identification
BOREAS Elevation Contours over the NSA and SSA in ARC/Info Generate Format
1.2 Data Set Introduction
This vector contour data set was prepared by BOReal Ecosystem-Atmosphere Study
(BOREAS) staff by reformatting the original data into the ARC/INFO Generate
format. These data cover portions of the BOREAS Northern Study Area (NSA) and
Southern Study Area (SSA) and are on a scale of 1:50,000.
1.3 Objective/Purpose
These data are provided as part of the BOREAS Staff Science Geographic
Information System (GIS) Data Collection Program-which included the collection of
pertinent map data in both hard-copy and digital form. The purpose of these data
is to provide the user with elevation contours of the Modeling Sub-Areas (MSAs).
These data can be used to create digital Elevation Models (DEMs) ofthe MSAs. The
original Standard Interchange Format (SIF) data were reformatted to the ARC/INFO
Generate format because it was considered difficult for an average user to
extract the contours from the SIF files.
1.4 Summary of Parameters
The parameters that are in the reformatted data are the elevation of the contour
(meters above mean sea level) and North American Datum 1983 (NAD83) Universal
Transverse Mercator (UTM) coordinate pairs (easting and northing) along the
contour.
1.5 Discussion
Based on information available to BOREAS Information system (BORIS) personnel,
these data were manually digitized from the National Topographic System (NTS) map
sheets at a scale of 1:50,000. The data were given to BOREAS staff in SIF and
K8A (the meaning of K8A is unknown) formats. C source code provided by the
BOREAS HYD-08 team was modified to read the contour data from various files. The
input data were understood to be in a standard format, but they were not standard
in terms of the software�s ability to consistently read all of the data files.
1.6 Related Data Sets
BOREAS HYD-8 Digital Elevation Models in UTM
BOREAS Vector Contours in SIF and K8A formats
2. Investigator(s)
2.1 Investigator(s) Name and Title
David Knapp
BORIS Information System Staff member
2.2 Title of Investigation
BOREAS Staff Science GIS Data Collection Program
2.3 Contact Information
Contact 1
----------
David Knapp
NASA/GSFC
Greenbelt, MD
(301) 286-1424
(301) 286-0239 (fax)
David.Knapp@gsfc.nasa.gov
Contact 2
----------
Jaime Nickeson
NASA/GSFC
Greenbelt, MD
(301) 286-3373
(301) 286-0239 (fax)
Jaime.Nickeson@gsfc.nasa.gov
3. Theory of Measurements
These data were not collected with any particular research in mind.
4. Equipment
4.1 Sensor/Instrument Description
Unknown.
4.1.1 Collection Environment
Unknown.
4.1.2 Source/Platform
Unknown.
4.1.3 Source/Platform Mission Objectives
The implied purpose of the NTS 1:50,000-scale map sheets was to provide users
with needed location and topographic information.
4.1.4 Key Variables
Elevation above mean sea level North Amercan Datum (NAD)83 Universal Transverse
Mercator (UTM) Coordinate Pairs
4.1.5 Principles of Operation
Unknown.
4.1.6 Sensor/Instrument Measurement Geometry
Unknown.
4.1.7 Manufacturer of Sensor/Instrument
Unknown.
4.2 Calibration
4.2.1 Specifications
Unknown.
4.2.1.1 Tolerance
Unknown.
4.2.2 Frequency of Calibration
Unknown.
4.2.3 Other Calibration Information
None.
5. Data Acquisition Methods
The data were acquired from the National Topographical Data Base and received
from the Canadian Centre for Remote Sensing (CCRS). The original data came in
SIF, digitized from 1:50,000-scale topographic maps.
6. Observations
6.1 Data Notes
None.
6.2 Field Notes
None.
7. Data Description
7.1 Spatial Characteristics
7.1.1 Spatial Coverage
The various data files cover parts of the BOREAS NSA-Modeling Sub-Area (MSA) and
SSA-MSA.
The two areas that are covered by these vector files include an area west of
Thompson, Manitoba (NSA), and an area north of Prince Albert, Saskatchewan (SSA).
Each of the following maps covers an area roughly 31.5km x 27.8km.
The following NTS map sheets are covered by the data:
For the NSA:
Number Name
------ --------------
63 O/10 Wuskwatim Lake
63 O/15 Nelson House
63 O/16 Noble Lake
63 O/09 Ospwagan Lake
63 P/14 Begg Lake
64 A/03 Orr Lake
64 A/04 Strong Lake
64 B/01 Harding Lake
64 B/02 Leftrook Lake
For the SSA:
Number Name
------ --------------
73 G/09 Halkett Lake
73 G/16 Waskesiu Lake
73 H/09 Torch River
73 H/10 Bedard Creek
73 H/11 Birchbark Lake
73 H/12 Emma Lake
73 H/13 Bittern Lake
73 H/14 Candle Lake
73 H/15 White Gull Creek
73 H/16 Falling Horse Creek
73 I/01 Scarth River
73 I/02 Summit Lake
73 I/03 Whiteswan Lake
73 I/04 Montreal Lake South
73 J/01 Crean Lake
The area covered by these sheets does not cover all of the area described by the
following bounding coordinates. These bounding areas are provided to give a
general idea of where these map sheets fall.
NSA-MSA
Longitude Latitude
--------- --------
Northwest 98.72W 56.055N
Northeast 98.09W 55.990N
Southeast 98.18W 55.726N
Southwest 98.81W 55.790N
SSA-MSA
Longitude Latitude
--------- --------
Northwest 105.18W 54.093N
Northeast 104.42W 54.053N
Southeast 104.48W 53.695N
Southwest 105.23W 53.735N
7.1.2 Spatial Coverage Map
Not available.
7.1.3 Spatial Resolution
The original contour interval of the data is 25 feet (7.62 m).
7.1.4 Projection
The data are in their original UTM projection. The NSA data are in UTM zone 14,
and the SSA data are in UTM zone 13.
7.1.5 Grid Description
Quantitative estimates were not made of the mean spacing between points along the
contour lines. Visual assessment of the data showed the spacing to be
appropriate for the 1:50,000 scale (i.e., there was no noticeable jaggedness or
discontinuities along the contours).
7.2 Temporal Characteristics
7.2.1 Temporal Coverage
Information regarding when the original source data were collected is sketchy.
Most of the maps from which these contours were digitized were made in the 1970s
or 1980s.
7.2.2 Temporal Coverage Map
Not available.
7.2.3 Temporal Resolution
Although these data were likely compiled from map and aerial photograph vintages
covering 10 or more years, they are considered to be a single reference data set.
7.3 Data Characteristics
7.3.1 Parameter/Variable
Elevation above mean sea level
NAD83 UTM coordinate pairs along a given elevation contour
7.3.2 Variable Description/Definition
Elevation above mean sea level - The vertical distance between a plane at mean
sea level and a parallel plane intersecting this point.
NAD83 UTM coordinate pairs along a given elevation contour - The NAD83-based UTM
easting and northing coordinate pairs that define the geographic locations over
which the given contour exists.
7.3.3 Unit of Measurement
Elevation above mean sea level - meters
NAD83 UTM coordinate pairs along a given elevation contour - UTM meters
7.3.4 Data Source
Geomatics Canada
Natural Resources Canada
615 Booth St.
Ottawa, Ontario K1A 0E9 CANADA
7.3.5 Data Range
NSA-MSA
Elevation
(meters)
-----------
Minimum: 206
Maximum: 381
SSA-MSA
Elevation
(meters)
------------
Minimum: 335
Maximum: 747
7.4 Sample Data Record
442
533084.00, 5939891.00
533079.00, 5939891.00
533061.00, 5939889.00
533033.00, 5939897.00
532950.00, 5939902.00
532877.00, 5939910.00
532849.00, 5939918.00
532784.00, 5939950.00
532747.00, 5939991.00
532714.00, 5940015.00
532539.00, 5940100.00
END
8. Data Organization
8.1 Data Granularity
The smallest amount of data obtainable is the entire set of vector contour files.
8.2 Data Format(s)
8.2.1 Uncompressed Data Files
The vector contour data set consists of a set of 24 files in the following order:
File 1: Data for Map 73 G/09 (400 bytes per record) SSA
File 2: Data for Map 73 G/16 (400 bytes per record)
File 3: Data for Map 73 H/09 (400 bytes per record)
File 4: Data for Map 73 H/10 (400 bytes per record)
File 5: Data for Map 73 H/11 (400 bytes per record)
File 6: Data for Map 73 H/12 (400 bytes per record)
File 7: Data for Map 73 H/13 (400 bytes per record)
File 8: Data for Map 73 H/14 (400 bytes per record)
File 9: Data for Map 73 H/15 (400 bytes per record)
File 10: Data for Map 73 H/16 (400 bytes per record)
File 11: Data for Map 73 I/01 (400 bytes per record)
File 12: Data for Map 73 I/02 (400 bytes per record)
File 13: Data for Map 73 I/03 (400 bytes per record)
File 14: Data for Map 73 I/04 (400 bytes per record)
File 15: Data for Map 73 J/01 (400 bytes per record)
File 16: Data for Map 63 O/09 (400 bytes per record)
File 17: Data for Map 63 O/10 (400 bytes per record)
File 18: Data for Map 63 O/15 (400 bytes per record)
File 19: Data for Map 63 O/16 (400 bytes per record)
File 20: Data for Map 63 P/14 (400 bytes per record)
File 21: Data for Map 64 A/03 (400 bytes per record)
File 22: Data for Map 64 A/04 (400 bytes per record)
File 23: Data for Map 64 B/01 (400 bytes per record)
File 24: Data for Map 64 B/02 (400 bytes per record)
The 24 data files each contain maximum record sizes of 400 bytes. Each physical
record on tape consists of 1 to 10 logical records of 40 bytes each. As noted
previously, the data in the files are stored in the ARC/INFO Generate format.
Within each file, the data in the 40-byte logical records are stored as American
Standard Code for Information Interchange (ASCII) characters. The records are
arranged in groups that contain varying numbers of records. The first record of
the group contains the value for the elevation above mean sea level. This is
followed by the records containing the UTM easting and northing coordinate pairs
for that elevation contour. At the end of each contour, a record containing the
ASCII characters �END� indicates the end of the contour. A second record
containing the ASCII �END� characters is given at the end of the contour groups
to indicate the end of the file. The following listing illustrates this format.
442 <-------- This is the contour�s elevation (meters)
533084.00, 5939891.00 <-------- This is the first of a series of UTM
533079.00, 5939891.00 coordinates (easting, northing) that
533061.00, 5939889.00 define the contour.
533033.00, 5939897.00
532950.00, 5939902.00
532877.00, 5939910.00
532849.00, 5939918.00
532784.00, 5939950.00
532747.00, 5939991.00
532714.00, 5940015.00
532539.00, 5940100.00
END <-------- This marks the end of this contour.
465 <-------- The elevation of the next contour.
531985.00, 5953858.00
531985.00, 5953866.00
531972.00, 5953881.00
531950.00, 5953891.00
531899.00, 5953894.00
531853.00, 5953913.00
531774.00, 5953915.00
531744.00, 5953899.00
...
531734.00, 5953875.00
531745.00, 5953826.00
531766.00, 5953808.00
END <----- This marks the end of this contour.
END <----- This marks the end of the file.
8.2.2 Compressed CD-ROM Files
On the BOREAS CD-ROMs, all the files listed in section 8.2.1 have been
compressed with the Gzip compression program (file name *.gz). These data have
been compressed using gzip version 1.2.4 and the high compression (-9) option
(Copyright (C) 1992-1993 Jean-loup Gailly). Gzip (GNU zip) uses the Lempel-Ziv
algorithm (Welch, 1994) used in the zip and PKZIP programs. The compressed files
may be uncompressed using gzip (-d option) or gunzip. Gzip is available from
many websites (for example, ftp site prep.ai.mit.edu/pub/gnu/gzip-*.*) for a
variety of operating systems in both executable and source code form. Versions
of the decompression software for various systems are included on the CD-ROMs.
9. Data Manipulations
9.1 Formulae
The only data value conversion performed by BORIS staff was to convert the
elevation measurements in feet in some (not all) of the files to meters. This
was done by dividing the elevation values of feet by 3.28 and then rounding the
result.
9.2 Data Processing Sequence
9.2.1 Processing Steps
BORIS staff processed the original data to the current product by:
1) Attempting to read a file with the provided software.
2) Modifying the C source code and updating the file header to read the specific
file.
3) Running the program to extract contours from the file and create output files.
4) Writing the output files to tape.
5) Copy the ASCII and compress the binary files for release on CD-ROM.
9.2.2 Processing Changes
None.
9.3 Calculations
9.3.1 Special Corrections/Adjustments
There appeared to be two types of files in the original set. In many cases, the
header information in each file had to be modified in order for the modified
software to extract the contours successfully.
9.3.2 Calculated Variables
See Section 9.1.
9.4 Graphs and Plots
None.
10. Errors
10.1 Sources of Error
One source of error is the digitizing process used to create the contours from
the map sheets. It is not known whether the maps were hand digitized or if
software was used to digitize the contours. In either case, the error is
probably negligible.
10.2 Quality Assessment
10.2.1 Data Validation by Source
Unknown.
10.2.2 Confidence Level/Accuracy Judgment
Unknown.
10.2.3 Measurement Error for Parameters
Unknown.
10.2.4 Additional Quality Assessments
None.
10.2.5 Data Verification by Data Center
After extracting the data into the ARC/INFO Generate files, BORIS staff plotted
the contour data and visually reviewed the data with the 1:50,000-scale hardcopy
maps. No anomalies or errors were detected in this review.
11. Notes
11.1 Limitations of the Data
Because the data have a 25-foot contour interval, variations in the terrain that
are smaller than 25 feet may not be detectable. The user should not expect to
see terrain detail such as small berms or other minor topographic relief.
11.2 Known Problems with the Data
The NSA maps from which these data were derived were found to be in disagreement
with BOREAS gathered and differentially corrected GPS coordinates by about 150
meters. The error did not appear to be systematic. The SSA maps have a higher
degree of accuracy (about 45 meters) when compared to GPS.
11.3 Usage Guidance
If these data are going to be used to create a DEM, the various vector files
should be edge-matched to create seamless contours that do not have
discontinuities at the map boundaries.
Before uncompressing the Gzip files on CD-ROM, be sure that you have enough disk
space to hold the uncompressed data files. Then use the appropriate
decompression program provided on the CD-ROM for your specific system.
11.4 Other Relevant Information
None.
12. Application of the Data Set
These data can be used to create a gridded DEM of the area of interest as well as
for graphical purposes, as an overlay along with other vector layers.
13. Future Modifications and Plans
None.
14. Software
C source code from HYD-8 for converting from SIF or K8A format.
14.1 Software Description
The software to read the SIF and K8A was originally produced by an unknown
source, although it was obtained from HYD-08. The software reads the input file
and extracts certain features based on feature codes that are supplied by the
user.
Gzip (GNU zip) uses the Lempel-Ziv algorithm (Welch, 1994) used in the zip and
PKZIP commands.
14.2 Software Access
The software is written in C and is operational on UNIX workstations at GSFC. The
software is available by contacting the ORNL DAAC or BOREAS Staff.
Gzip is available from many websites across the net (for example) ftp site
prep.ai.mit.edu/pub/gnu/gzip-*.*) for a variety of operating systems in both
executable and source code form. Versions of the decompression software for
various systems are included on the CD-ROMs.
15. Data Access
15.1 Contact Information
Primary contact:
Ms. Beth McCowan
BOREAS Data Manager
NASA/GSFC
Greenbelt, MD
(301) 286-4005
(301) 286-0239 (fax)
beth@ltpmail.gsfc.nasa.gov
15.2 Data Center Identification
See Section 15.1.
15.3 Procedures for Obtaining Data
Users may place data requests by telephone, electronic mail, or fax.
15.4 Data Center Status/Plans
The NSA and SSA elevation contour data are available from the Earth Observing
System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL)
Distributed Active Archive Center (DAAC).
The BOREAS contact at ORNL is:
ORNL DAAC User Services
Oak Ridge National Laboratory
(865) 241-3952
ornldaac@ornl.gov
ornl@eos.nasa.gov
16. Output Products and Availability
16.1 Tape Products
The vector contour data can be made available on 8-mm, Digital Archive Tape
(DAT), or 9-track tapes at 6250 or 1600 Bytes Per Inch (BPI).
16.2 Film Products
None.
16.3 Other Products
These data are available on the BOREAS CD-ROM series.
17. References
17.1 Platform/Sensor/Instrument/Data Processing Documentation
Welch, T.A. 1984, A Technique for High Performance Data Compression, IEEE
Computer, Vol. 17, No. 6, pp. 8 - 19.
17.2 Journal Articles and Study Reports
Sellers, P., F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan.
Version 1994-3.0, NASA BOREAS Report (EXPLAN 94).
Sellers, P., F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan.
Version 1996-2.0, NASA BOREAS Report (EXPLAN 96).
Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere
Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94).
Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere
Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96).
Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J.
Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E.
Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and
early results from the 1994 field year. Bulletin of the American Meteorological
Society. 76(9):1549-1577.
Sellers, P., F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press).
17.3 Archive/DBMS Usage Documentation
None.
18. Glossary of Terms
None.
19. List of Acronyms
ASCII - American Standard Code for Information Interchange
BOREAS - Boreal Ecosystem-Atmosphere Study
BORIS - BOREAS Information System
BPI - Bytes Per Inch
CCRS - Canadian Centre for Remote Sensing
CD-ROM - Compact Disk-Read-Only-Memory
DAAC - Distributed Active Archive Center
DAT - Digital Audio Tape
DEM - Digital Elevation Model
EOS - Earth Observing System
EOSDIS - EOS Data and Information System
GIS - Geographic Information System
GMT - Greenwich Mean Time
GSFC - Goddard Space Flight Center
MSA - Modeling Sub-Area
NAD27 - North American Datum 1927
NAD83 - North American Datum 1983
NASA - National Aeronautics and Space Administration
NSA - Northern Study Area
NTS - National Topographic System
ORNL - Oak Ridge National Laboratory
PANP - Prince Albert National Park
SIF - Standard Interchange Format
SSA - Southern Study Area
URL - Uniform Resource Locator
UTM - Universal Transverse Mercator
WWW - World Wide Web
20. Document Information
20.1 Document Revision Date(s)
Written: 09-Jun-1995
Last Updated: 22-Jan-1998
20.2 Document Review Date(s)
BORIS Review: 06-Jun-1997
Science Review:
20.3 Document ID
20.4 Citation
These data originated as vector data that were provided to BORIS staff through
CCRS by Geomatics Canada. The contribution of the data by CCRS and Geomatics
Canada and processing of the data by BORIS staff are greatly appreciated.
20.5 Document Curator
20.6 Document URL
Keywords
-----------------
Elevation Contours
NSA_SSA_Elev_Contours.doc
04/17/98