BOREAS Forest Cover Data Layers over the SSA-MSA in Raster Format Summary This data set was prepared by BORIS staff by processing the original vector data into raster files. The original data were received as ARC/INFO coverages or as export files from SERM. The data include information on forest parameters for the BOREAS SSA MSA. The data are stored in binary, image format files. Note that the binary 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 Forest Cover Data Layers over the SSA-MSA in Raster Format 1.2 Data Set Introduction The forest cover data layers were created in raster form from the vector polygon forest cover data provided by Saskatchewan Environment and Resource Management, Forestry Branch - Inventory Unit (SERM-FBIU). The forest cover data layers created for this product are species cover, canopy closure, height, and year. 1.3 Objective/Purpose These data are provided as part of the BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Geographical Information system (GIS) Data Collection Program, which included the collection of pertinent map data in both hard copy and digital form. This data set, originally provided as vector polygons with attributes, has been processed to provide raster files that can be used for modeling or for comparison purposes. 1.4 Summary of Parameters The parameters that are in the raster data include species association (cover type), crown closure, height class, and decadal year of stand origin or disturbance. 1.5 Discussion Based on a review of the data and discussions with SERM personnel and BOREAS scientists, BOREAS Information System (BORIS) staff processed the original vector data into raster data layers. A full description of the data layer derivations is given in Section 9. 1.6 Related Data Sets BOREAS Forest Cover Data Layers of the NSA-MSA in Raster Format SERM Forest Cover Data Layers of the SSA in Vector Format SERM Forest Fire Chronology of Saskatchewan in Vector Format SERM Forest Cover Data of Saskatchewan in Vector Format Prince Albert National Park Forest Cover Data in Vector Format 2. Investigator(s) 2.1 Investigator(s) Name and Title BOREAS Staff 2.2 Title of Investigation BOREAS Staff Science GIS Data Collection Program 2.3 Contact Information Contact 1 ---------- Fern Gruszka Saskatchewan Environment and Resource Management Prince Albert, SK CANADA (306)953-2360 gruszka@larix.derm.gov.sk.ca Contact 2 ---------- Jaime Nickeson NASA/GSFC Greenbelt, MD (301) 286-3373 (301) 286-0239 (fax) Jaime.Nickeson@gsfc.nasa.gov 3. Theory of Measurements SERM-FBIU maintains in its inventory unit a GIS of forest inventory information for Saskatchewan. This inventory is maintained primarily for use by forest managers for silvicultural purposes, and it contains a wealth of information that can be of use in Earth resources analyses and ecosystem modeling either in its raw form or as a derived product such as this one. 4. Equipment 4.1 Sensor/Instrument Description The original polygon data were digitized from 1:12,500-scale forest cover maps. The maps were derived from black-and-white 1:12,500-scale infrared aerial photography and field reconnaissance notes. No information is known about the original digitizing equipment or procedures and criteria used in the digitizing process. 4.1.1 Collection Environment These original vector data were acquired as ARC/INFO vector coverages or in ARC/INFO export format. The data were produced by SERM-FBIU. No specific information other than the scale of the resulting photography is known about the aircraft flights or the equipment that was used to collect the aerial photography. 4.1.2 Source/Platform Unknown. 4.1.3 Source/Platform Mission Objectives Unknown. 4.1.4 Key Variables The key variables of this data set are species cover, crown closure, height class, and decadal year of stand origin or disturbance. 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 Unknown. 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 SERM personnel created the forest cover maps by transcribing information from photo-interpreted 1:12,500-scale black-and-white infrared aerial photography and field reconnaissance notes. 6. Observations 6.1 Data Notes None. 6.2 Field Notes The field notes used in compiling the original forest cover data are available from SERM-FBIU. See Section 2.3. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage This data set covers a portion of the BOREAS Southern Study Area (SSA) and encompasses most of the associated SSA-Modeling Sub-Area (MSA). The corners of the actual raster data files are: BOREAS BOREAS West North Point X (km) Y (km) Longitude Latitude --------------------------------------------------------------- Upper Right 425.160 360.840 104.49043 54.06416 Upper Left 381.870 360.840 105.14995 54.09860 Lower Left 381.870 326.490 105.19373 53.79137 Lower Right 425.160 326.490 104.53910 53.75717 These locations represent the outside corners of the corner pixels. 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution These data were gridded to a cell size of 30 m. 7.1.4 Projection The area mapped is projected in the BOREAS grid projection, which is based on the ellipsoidal version of the Albers Equal-Area Conic (AEAC) projection. The projection has the following parameters: Datum: North American Datum 1983 (NAD83) Ellipsoid: Geodetic Reference System GRS80 or WGS84 Origin: 111.000° West Longitude 51.000° North Latitude Standard Parallels: 52° 30' 00" N 58° 30' 00" N Units of Measure: kilometers 7.1.5 Grid Description The data are gridded in 30-m intervals based on the ellipsoidal version of the AEAC projection with standard parallels of 52° 30' N and 58° 30' N and a lower left origin of 51° N and 111° W. 7.2 Temporal Characteristics Most of the data used for this product were acquired by BORIS in 1993. The maps from which the data are derived are completely reinventoried on a 10 to 20-year cycle by SERM, except for disturbed areas, which are updated annually. BORIS acquired the data in 1993; the forest cover layers have not yet had any inventory updates. 7.2.1 Temporal Coverage These maps were produced from aerial photography taken as recently as 1988. The data base maintained by SERM is updated as needed based on fires, cutting, or other disturbances. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution As noted, the original maps are completely reinventoried by SERM personnel on a 10- to 20-year cycle, except for disturbed areas, which are updated annually. The photographs and other information used to create the original vector data set most likely covered the 10- to 20-year period prior to 1988 and any updates made from then to 1993, when the data were acquired. 7.3 Data Characteristics 7.3.1 Parameter/Variable Species Association (cover type) Crown Closure Height Class Year of Stand Origin or Disturbance 7.3.2 Variable Description/Definition Species Association - The vegetative species association covering the given area as derived by BORIS personnel. See Section 9 for derivation details. Crown Closure: The crown closure category specified in the original data set. See Section 9 for derivation details. Height Class: The height class of the vegetation covering the area. See Section 9 for class details. Year of Stand Origin or Disturbance: The decade in which the vegetation in the area originated or the year it was last disturbed. See Section 9 for coding details. 7.3.3 Unit of Measurement The values in each of the data layers are described as follows: SPECIES ASSOCIATION (COVER TYPE) Binary Number value in file Definition ----- ------- ------------------- 0 317185 border pixels 11 3415 White Spruce (WS) 12 169411 Black Spruce (BS) 13 171532 Jack Pine (JP) 14 10126 Tamarack (TL) 21 202620 Spruce/Pine 31 24728 Mix Spruce Fir/Broadleaf 32 156003 Mix Jack Pine/Broadleaf 51 23902 Mix Broadleaf/Spruce-Fir 52 48546 Mix Broadleaf/Jack Pine 71 12079 Aspen 101 322405 treed muskeg 103 58898 clear muskeg 105 26976 brushland 107 12180 clearing 109 23129 burn-over (nonprod) 112 17638 disturb, cut or burn 113 1100 disturb, JP regeneration 118 30 experimental area 121 959 flooded land 122 49373 water CROWN CLOSURE (DENSITY) Binary Number value in file definition ----- ------- --------------- 0 830069 nonproductive or border pixels 61 11080 10% < CC <= 30% 62 93651 30% < CC <= 55% 63 403725 55% < CC <= 80% 64 313710 80% < CC HEIGHT CLASS value npixels definition ----- ------- -------------------- 0 830088 nonproductive or border pixels 5 176609 2.5m < hgt <= 7.5m 10 248422 7.5m < hgt <= 12.5m 15 310962 12.5m < hgt <= 17.5m 20 68612 17.5m < hgt <= 22.5m 25 17542 22.5m < hgt YEAR OF STAND ORIGIN or DISTURBANCE value npixels definition ----- ------- ----------------- 0 811127 nonproductive or border pixels 82 33 1815-1825 Year of stand origin 83 1378 1825-1835 84 2496 1835-1845 85 18158 1845-1855 86 30086 1855-1865 87 12824 1865-1875 88 62706 1875-1885 89 90075 1885-1895 90 104530 1895-1905 91 75163 1905-1915 92 116326 1915-1925 93 30494 1925-1935 94 112734 1935-1945 95 10165 1945-1955 96 2283 1955-1965 97 39688 1965-1975 98 113392 1975-1985 176 103 1976 Year of disturbance 177 51 1977 180 51 1980 183 8 1983 184 7232 1984 185 4951 1985 186 6181 1986 7.3.4 Data Source The original data were acquired in ARC/INFO format from: Saskatchewan Environment and Resource Management Forestry Branch - Inventory Unit 800 Central Ave. Prince Albert, Saskatchewan Canada S6V 6G1 The original data were gridded into a binary image format for the SSA-MSA by BORIS personnel. 7.3.5 Data Range Species Association 0 - 122 Crown Closure 0 - 64 Height Class 0 - 25 Year of Stand Origin or Disturbance 0 - 186 7.4 Sample Data Record Not applicable. 8. Data Organization The raster data are stored on tape as single-byte band-sequential binary files. 8.1 Data Granularity The smallest amount of obtainable data is the entire data set containing the four raster layers and other supporting files. 8.2 Data Format(s) 8.2.1 Uncompressed Data Files The data files include: Record Number of File Description Size (Bytes) Records Bytes/Pixel ------------------------------------------------------------------------- 1 Header File 80 19 N/A 2 SPECIES COVER 1443 1145 1 3 CROWN CLOSURE 1443 1145 1 4 HEIGHT 1443 1145 1 5 YEAR 1443 1145 1 6 AML 1 (calc cover, year) 80 79 N/A 7 AML 2 (create grid, combine) 80 129 N/A 8 AMK 3 (reprojection info) 80 10 N/A The data set consists of eight files. The first file is the header file which contains 80-byte records of American Standard Code for Information Interchange (ASCII) characters that describe the general content of the data set. Files 2 through 5 contain the binary raster data layers. Each raster layer contains 1,443 8-bit (1-byte) values in each of 1,145 lines. Files 6 through 8 contain ASCII files that provide examples of the type of ARC Macro Language (AML) files used to create this data set from the original vector data. These files were not intended to be used directly; they are merely examples of the process undertaken to produce the provided data set. 8.2.2 Compressed CD-ROM Files On the BOREAS CD-ROMs, files 1, 6, 7, and 8 listed above are stored as ASCII text files; however, files 2 - 4 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 The original data were acquired as ARC/INFO export files, one file per 10-km x 10-km area. The data were imported into ARC, and attributes of the coverage polygons were manipulated within AML scripts to produce new attributes. The new attributes were used as lookup tables for gridding the data, and the separate maps were then mosaicked together into one map for each layer/attribute. The relevant attributes (items) associated with each polygon in the vector data are as follows: Item Description SP10 Primary Species #1 (one of 13 possible tree species) SP11 Primary Species #2 (same as SP10) SP12 Primary Species #3 (same as SP10) SP20 Secondary Species #1 (same as SP10) HGT Height Class (one of 5 classes in 5-m intervals) D Density (crown closure, see below) YOO Decadal Year of Stand Origin MLEVEL Management Level (12 rarely used codes for non-forested polygons) SYR Year of Source (year source info. for a polygon was obtained) YSP Year of Silvicultural Activity (also rarely used) R1 Regenerating Species 1 (as in SP10, but may not be tree species) DIST Disturbance Type (cut-over or partial cut, by season, or burn-over) DYR Year of Disturbance NP Nonproductive Type (codes to identify all nonforested polygons) The data layers created for this product were derived from the above attributes as follows: Raster Layer Input Vector Items -------------- ------------------------------------------------ COVER SA, SP10, SP11, SP12, SP20, MLEVEL, R1, DIST, NP CROWN CLOSURE D HEIGHT HGT YEAR YOO, YSP, DIST, SA, SYR, DYR NP 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms The species association data use the items listed above to select one of the 18 species associations as defined by SERM, who provided the data. The minimum size for homogeneous forest stands varies from 1-4 hectares depending upon the size (HGT) and economic value of the species. The crown closure data were created using the D item within the coverages. This item is the average percent crown closure of the forest stand and is assigned to one of four classes. The boundaries of these classes are given in the table in Section 8.2. Values for item D exist only for forested polygons. The height class data were created from the HGT item within the coverages. The average height of all living trees in the main canopy of the stand is assigned to one of five height classes. The limits of the height classes are given in Section 8.2. Values for item HGT exist only for forested polygons. The decadal year of origin or disturbance data were derived from a combination of the items listed above. In the table in Section 8.2, year of silvicultural treatment and year of disturbance are coded similarly. The ages of productive polygons were assigned to decadal classes. When ages overlap two or more classes, the older class is usually chosen. Values for the year-associated items exist only for forested or disturbed polygons. 9.2 Data Processing Sequence 9.2.1 Processing Steps Most of the following processing steps were performed in ARC/INFO. 1) New attribute items were added to the attribute files of each coverage to store the value that would represent cover, crown closure, and year of stand origin. 2) HGT was already a numeric item and could be used directly as a lookup table for gridding the height layer. 3) Crown closure was not numeric, but levels were easily converted to a numeric item that was used to grid the height layer. 4) New values were assigned to the new cover item using the SERM definition of species association, which assigns one of 18 common boreal associations from the many possible combinations of the SP10, SP11, and SP12 (only 10 different species associations show up in this data set). 5) Management level, regenerating species, disturbance type, and nonproductive code were used to assign cover values for nonforested polygons. 6) To calculate the year item, the year of stand origin item was used for forested polygons, and year of disturbance or source year were used for nonforested polygons. 7) The numeric items created for cover and year were then used to grid the polygons for those layers. 8) The individual maps that had been gridded were mosaicked using the ARC function GRIDINSERT. 9) The resulting Universal Transverse Mecator (UTM) layer maps were reprojected in ARC to create the raster images in the BOREAS grid projection. 10) The gridded layers and other information files were written to tape for distribution. 11) 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 None. 9.3.2 Calculated Variables None. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error There is the possibility of coding errors in the attributes, transcription errors from original sample data, and photo-interpretation errors. 10.2 Quality Assessment 10.2.1 Data Validation by Source Unknown. 10.2.2 Confidence Level/Accuracy Judgment The accuracy of the gridding procedure is high. Some consideration should be given to the scale of the data and what will be inferred from it. 10.2.3 Measurement Error for Parameters Unknown. 10.2.4 Additional Quality Assessments None. 10.2.5 Data Verification by Data Center Each gridded image was checked visually to make sure that the gridding procedure assigned a digital number (DN) to each attribute value. The data were also checked for gaps of "no data" along the seams of the 10-km x 10-km coverages used to compile this product. 11. Notes 11.1 Limitations of the Data BORIS acquired these data in 1993; therefore, areas subjected to logging activity or other disturbance, such as fire, will appear much different today as compared to the forest cover data. 11.2 Known Problems with the Data None. 11.3 Usage Guidance Saskatchewan Parks and Renewable Resources does not accept any liability for decisions or action taken on the basis of these data. 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 Saskatchewan Parks and Renewable Resources also maintains stand and stock tables, 3P plots, and possibly some permanent sample plots in this area. Aerial photographic prints and negatives are also available. Contact the agency directly if you are interested in such information or if you wish to acquire those data. 12. Application of the Data Set This data set would provide good reference information for assessing spectral image data classification techniques over the area and serve as an initial baseline data set for analyzing land cover and vegetation change. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description The Environmental Systems Research Institute (ESRI) ARC/INFO (Version 7.0) package was used to perform the data manipulation and processing. Questions about the software should be directed to: Environmental Systems Research Institute, Inc. 380 New York Street Redlands, CA 92373-8100 Gzip (GNU zip) uses the Lempel-Ziv algorithm (Welch, 1994) used in the zip and PKZIP commands. 14.2 Software Access ARC/INFO is a commercial package; contact ESRI for details. 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 Ms. Beth Nelson BOREAS Data Manager NASA GSFC Greenbelt, MD (301) 286-4005 (301) 286-0239 (fax) Elizabeth.Nelson@gsfc.nasa.gov 15.2 Data Center Identification See Section 15.1. 15.3 Procedures for Obtaining Data Users may place requests by telephone, electronic mail, or fax. 15.4 Data Center Status/Plans As the BOREAS data are processed and sufficiently quality checked, they will be 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 None. 16.2 Film Products None. 16.3 Other Products These data are available on the BOREAS CD-ROM series. 17. References Lindenas, D. G. June 1985. Forest Inventory Interpretation and Mapping Manual - Specifications for the Interpretation and Mapping of Aerial Photographs in the Forest Inventory Section. Saskatchewan Parks and Renewable Resources 17.1 Platform/Sensor/Instrument/Data Processing Documentation ARC/INFO User's Guide (Version 7), 1994. Redlands, CA. 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.and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P.and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P.and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue. 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.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. (1997). "BOREAS in 1997: Experiment Overview, Scientific Results and Future Directions", Journal of Geophysical Research (JGR), BOREAS Special Issue, 102(D24), Dec. 1997, pp. 28731-28770. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms AEAC - Albers Equal-Area Conic AML - ARC Macro Langauge ASCII - American Standard Code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BS - Black Spruce DAAC - Distributed Active Archive Center DN - Digital Number EOS - Earth Observing System EOSDIS - EOS Data and Information System ESRI - Environmental Systems Research Institute GSFC - Goddard Space Flight Center GIS - Geographic Information System JP - Jack Pine NASA - National Aeronautics and Space Administration NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park SERM - Saskatchewan Environment and Resource Management SSA - Southern Study Area TL - Tamarack URL - Uniform Resource Locator (a World Wide Web address) WS - White Spruce 20. Document Information 20.1 Document Revision Dates Written: 01-Aug-1994 Last Updated: 28-Jul-1998 20.2 Document Review Dates BORIS Review: 15-May-1997 Science Review: 20.3 Document ID 20.4 Citation The original data were provided by SERM-FBIU. The vector data were processed and gridded by BORIS staff. The contribution of the vector data by SERM and the processing of the data by BORIS staff are greatly appreciated. 20.5 Document Curator 20.6 Document URL Keywords Forest Cover Forestry Forest Inventory GIS SSA_For_Cov_Raster.doc 08/18/98