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Transboundary Site Index Mapping
Nathan Walker, Audubon Alaska, GIS Biologist
This dataset was created in order to facilitate transboundary conservation work and research projects, by integrating land cover maps into a single dataset from Cape Caution, BC, to Yakutat Bay, AK. It includes three levels of land classification, site index, elevation, hydric soils (yes/no), karst (yes/no), primary and secondary species, size class, and volume class. It also includes a number of other important attributes from individual datasets, which were not crosswalked between the different areas. This file represents site index, or the number of meters trees would be expected to grow in 50 years.
This dataset was created in order to facilitate transboundary conservation work and research projects, by integrating land cover maps into a single dataset from Cape Caution, BC, to Yakutat Bay, AK. This file represents site index, or the number of meters trees would be expected to grow in 50 years.
Time Period of Content
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Point of Contact
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Browse Graphic Caption:
Regional overview of the dataset.
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Please cite Audubon Alaska and the data contributors listed in the Credits section in any products derived from these data. Data source constraints information provided below:VRI, BTM, and karst data:BC data is provided by the Province of British Columbia under the Open Government License for Government of BC Information v.BC1.0 (license information viewable at
land cover data:The Nature Conservancy shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any sale, distribution, loan, or offering for use of these digital data, in whole or in part, is prohibited without the approval of the Nature Conservancy. The use of these data to produce other GIS products and services with the intent to sell for a profit is prohibited without the written consent of the Nature Conservancy. All parties receiving these data must be informed of these restrictions. The Nature Conservancy shall be acknowledged as data contributors to any reports or other products derived from these data.Alaska land cover, harvest, site index data: The Forest Service uses the most current and complete data available. GIS data and product accuracy may vary. They may be developed from sources of differing accuracy; accurate only at certain scales; based on modeling or interpretation; incomplete while being created or revised; etc. Using GIS products for purposes other than those for which they were created, may yield inaccurate or misleading results. The Forest Service reserves the right to correct, update, modify or replace GIS products without notification. Any hardcopy or electronic products utilizing these data sets shall clearly indicate their source. If the user has modified the data in any way, they are obligated to describe the types of modifications they have performed. User specifically agrees not to misrepresent these data sets, nor to imply that the US Forest Service, Tongass National Forest approved the changes.Canadian Digital Elevation Dataset:The Licensee shall identify GeoBase® as a data source where any of the Data are redistributed, or contained within Derivative Products, and use of the Data shall not be construed as an endorsement by GeoBase® of those Derivative Products. License information viewable at :
Elevation Data:None. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Glacier Bay National Park land cover data:The Information Resource does not contain any sensitive information. No copyrights or other ownership issues. There are no distribution restrictions based solely on the proprietary evaluation.
Place Keyword Thesaurus:
Canada, Alaska, North America, Western British Columbia, United States, Southeast Alaska
Data Quality Information
Logical Consistency Report:
Land classification codes were assigned to each land classification class, and the codes for each level were appended into a single field; this field was then reviewed for contradictory information (e.g. LC1 = Water, LC 2 = Forest).
Of the initial planned extent, this excludes only land cover for the Yukon territory, and some minor no data holes and slivers (mostly along the border between Alaska and BC, in areas covered by neither dataset). The no data holes were filled with elevation data, but otherwise contain no attributes.
Varies depending on source data.
Step 1 Process Description:
D) Combined 1. Created template with relevant fields, merged in data from Alaska, Glacier Bay, BC, and BTM. 2. At this point, we discovered that some no-data holes, and slivers along the border remained in the dataset. These fell into two categories: places where no data were available in either dataset, and places where data from the VRI dataset had been left out (mostly in spots where the BTM dataset had been used to replace VRI data, but no BTM data had been available). For those areas where data were not available for any dataset, elevation was calculated. This was done using AK_BC_Blend: unlike previous elevation calculations, which were done entirely on the basis of a single dataset (AK_BC_50 prioritized Alaska, meaning that the BC data didn’t actually apply), these slivers included both BC and AK; for this reason, the AK and BC datasets were mosaicked a second time, this time using the blend operator. 3. We then joined these back to the sliver dataset, and appended the sliver dataset to previously created merge. 4. For the data gaps where VRI data had been available, first we converted the transboundary dataset to a raster and reclassed it such that all data had a value of 1, and no data had a value of 0. 5. Converted this raster to a polygon, and used a definition query to remove all the polygons with a value of 1. 6. Clipped the VRI polygon-to-raster-to-polygon file to the polygon file created in the previous step. 7. Used zonal stats to calculate elevation for these polygons using the AK_BC_Blend raster; joined these and the original VRI data back to these polygons. 8. Appended to the previously created-merge. (These were assigned a Dataset of “VRI” but a Project of ‘ “Slivers: “ & original Project entry,’ so that these records could be identified, and linked back to the original dataset if necessary, using the source ID field. 9. Ran attribute and spatial index on dataset. 10. Applied crosswalks (see crosswalk spreadsheet). 11. Created join table linking different land classification descriptions to land classification codes; joined this to dataset and transferred codes. 12. Created field appending the three LC codes, and exported a summary table of these values; reviewed table to identify, repair errors. 13. Created metadata.
Step 1 Process Date:
Step 2 Process Description:
This file was created from the dataset Tranboundary_Database using the following method: 1) Batch Selected features in 100,000-feature segments, breaking the dataset up into 65 smaller files. 2) Batch Simplified Polygon on each of these feature classes, Point Remove method, at 1 m maximum offset, no minimum area, no check for topological areas, and not keeping collapsed points. 3) Batch Dissolved based on field SIm_Int, which was created by rounding the SI_m field to the nearest integer value; features with a SIm_Int value of null or 0 were excluded from this. 4) Merged all of these dissolved feature sets back into a single file.
Step 2 Process Date:
Step 3 Process Description:
C) Alaska 1. Converted tsys_dbase to polygons, without simplifying polygons. 2. Erased GLBA (excluding unclassified polygons) and VRI features. 3. Used zonal statistics as table to calculate mean elevation (AK_BC_50) for each polygon. 4. Used zonal statistics as table to calculate mean site index (AK_BC_50) for each polygon; joined this, elevation table, and original tsys data back to polygons.
Step 3 Process Date:
Spatial Reference Information
Horizontal Datum Name:
D North American 1983
Denominator of Flattening Ratio:
Available for download in a zipped file geodatabase format at
See access and use constraints information.
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Metadata Reference Information
Metadata Creation Date:
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Metadata Standard Name:
FGDC Content Standard for Digital Geospatial Metadata
Metadata Standard Version:
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