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