The Arctic - Boreal Vulnerability Experiment (ABoVE) has developed two standardized spatial data products to expedite coordination of research activities and to facilitate data interoperability. The ABoVE Study Domain encompasses the Arctic and boreal regions of Alaska, USA, and the western provinces of Canada, North America. Core and Extended study regions have been designated within this Domain and are provided in both a vector representation (Shapefile) and a raster representation (GeoTIFF at 1,000-meter spatial resolution). A standard Reference Grid System has been developed to cover the entire Study Domain and also extends to the eastern portion of North America. This Reference Grid is provided as nested polygon grids at scales of 240, 30, and 5 meter spatial resolution. The 5 meter grid is new in Version 2. Note that the designated standard projection for the all ABoVE products is the Canadian Albers Equal Area projection.
Figure 1. ABoVE spatial data products - the Study Domain with Core and Extended study regions displayed and the Standard Reference Grid showing the nested 240 meter, 30 meter and 5 meter tiling scheme. Left: The location of sample tile Bh002v003 (in purple) within both the larger âAâ grid (in bold) and the smaller âBâ grid. Right: The location of sample tile Ch014v020 within the larger two grids is shown.
The Arctic - Boreal Vulnerability Experiment (ABoVE) has developed two standardized spatial data products to expedite coordination of research activities and to facilitate data interoperability. The ABoVE Study Domain encompasses the Arctic and boreal regions of Alaska, USA, and the western provinces of Canada, North America. Core and Extended study regions have been designated within this Domain and are provided in both a vector representation (Shapefile) and a raster representation (GeoTIFF at 1,000-meter spatial resolution). A Standard Reference Grid System has been developed to cover the entire Study Domain and also extends to the eastern portion of North America. This Reference Grid is provided as nested polygon grids at scales of 240, 30, and 5-meter spatial resolution. The 5-meter grid is new in Version 2.
The ABoVE Study Domain encompasses the Arctic and boreal regions of Alaska, USA, and the western provinces of Canada, North America. Core and Extended study regions have been designated within this Domain. The Core Region encompasses a range of landscapes, with areas that are rapidly changing in complex ways in response to global-scale climate change as well as regional-scale disturbances, and others that are not. This combination will allow for studies of both vulnerability and resilience. The Extended Region, outside of the Core Region, is needed for study of a subset of important changes that are unique to these regions (for example, insect outbreaks and forest dieback in the southern boreal forest). The Extended Region provides additional opportunities for research where environmental conditions are considered to be antecedent to those in the Core Region, as well collaboration on research being sponsored by partners.
The domain for the ABoVE study area is over 6.3 x 106 km2. Within the ABoVE campaign, many thematic data products will be generated from field measurements, flux towers, airborne remote sensors and satellite remote sensing data. The data sets will range considerably in resolution, format, geographic extent, projection and/or reference system.
The standardized Reference Grid and projection will enable researchers to identify, align and subdivide data products in order to facilitate archiving and distribution of datasets (both for long-term archiving of the data and near-term use throughout the campaign’s duration), and simplifies data standardization for scientific analysis within ABoVE.
ABoVE reference grid for the three spatial resolutions.
ABoVE_Study_Domain.tif ABoVE Study Domain as a raster file. This file provides a raster representation of the core and extended ABoVE study domain.
Value A unique value representing the core (Value = 1) and extended (Value = 2) ABoVE Study Domain.
The core and extended regions within the ABoVE Study Domain provide the opportunity to carry out research needed to address key research questions and objectives for understanding how environmental change is causing changes to social-ecological systems across the Arctic and boreal region of western North America.
The Core Region of the Study Domain captures the regional-scale variation in surface and atmospheric conditions necessary for the research addressing the second tier science questions and objectives of ABoVE. The Core Region encompasses a range of landscapes, with areas that are rapidly changing in complex ways in response to global-scale climate change and regional-scale disturbances as well, as others that are not - a combination that will allow for the studies on both vulnerability and resilience.
The Study Domain also includes an Extended Region outside of the Core Region that is needed for study of a subset of important changes that are unique to these regions (for example, insect outbreaks and forest dieback in the southern boreal forest). The Extended Region provides additional opportunities for research where environmental conditions are considered to be antecedent to those in the Core Region, as well as to collaborate on research being sponsored by partners.
The ABoVE field campaign will provide the opportunity to expand and coordinate a set of focused, interdisciplinary research activities designed to further understand the causes and consequences of change in the social-ecological systems of the Arctic and boreal regions of western North America. The campaign is expected to result in the development of multiple geospatial datasets. To facilitate data interoperability, a standard projection and reference grid have been proposed to cover the ABoVE study domain.
Thematic data products will be generated from field measurements, flux towers, airborne remote sensors and satellite remote sensing data. The datasets will range considerably in resolution, format, geographic extent, projection and/or reference system. This variability in ABoVE datasets is likely to place a considerable burden on individual researchers as they will need to standardize the incoming datasets to support geospatial analysis, thus leading to duplicated effort across research groups utilizing these products. This duplication of effort will continue to propagate as outcomes of scientific analysis from individual research groups will require subsequent standardization to support their further inclusion in ABoVE science projects.
Implementing a standard projection and grid enables the producers of the data to align and subdivide data products in order to ease archiving and distribution of datasets (both for long-term archiving of the data and near-term use throughout the campaign’s duration), and simplifies data standardization for scientific analysis within ABoVE. This compatibility across multiple datasets facilitates interoperability of the datasets in scientific analysis, and is an important benefit of the standardized projection and reference grid.
Additionally, it is expected that many data products will be generated with medium to fine resolution (30-m spatial resolution or less) imagery and hence would be too large to distribute to users as single files covering the entire study region. Where the projection provides a mechanism to ensure that the products are geometrically compatible, the reference grid provides a standardized way to break the files up into units that are easy to download and manipulate by the researchers.
Gridded ABoVE datasets of the extent larger than 100 X 100-km2 are to be produced in this grid and projection (this is roughly a Landsat tile). It is recognized that, at very high resolution, reprojection of original data can result in substantial special shifts in orientation, location, and shape of small objects; therefore, ABoVE science team members are encouraged to submit their fine-scale datasets in the original projection in addition to the ABoVE grid format (if the extent of their dataset is greater or equal to 10,000-km2) or only in the original projection if it is smaller than that size.
The reference grid naming convention is modeled after the MODIS grid using horizontal (h) and vertical (v) offsets from the upper left corner to describe the tile. For example in the left Figure 1-A (showing the large grid) the tile in the upper left corner is referred to as “h000v000” and the tile in the lower right corner is referred to as “h005v003”. The right Figure 1-B shows the smaller grid nested inside the larger grid. For each of the large tiles there is a series of small tiles nested inside. The large grid is referred to as “A”, the medium grid is referred to as “B”, and the small grid is referred to as “C”.
To simplify downstream processing it is recommended that all products use three digit identifiers for all grid tile identifiers (i.e. Ch014v020 instead of h14v20) to facilitate scripting in analyses later on.
The ABoVE Reference Grid is applicable mainly for raster-based products derived for the study domain (but does not apply to circumpolar datasets). The grid has been designed to cover the entire study domain, and extends to the eastern portions of North America (see Figure 1) to accommodate any products that are looking at continental scale processes. This grid is similar to the MODIS tiling scheme and is a nested set of grids provided at scales of 240, 30, and 5 meter spatial resolution, such that products from MODIS, Landsat, and very high spatial resolution (VHR) data would be compatible within the grid. It is easily scalable for products of 1 meter to 10 kilometers by switching from one grid resolution to another as the resolution gets coarser.
Hence Ch036v012 is in Ah001v000. Translating from the B-grid to the A-grid is the same as translating from C-grid to B-grid, simply divide h and v by 6.
Hence Bh010v008 is in Ah001v001. This simple translation method can facilitate analysis that requires using multiple products at varying spatial resolutions.
1. While the projection would be applicable to multiple data types, the grid would primarily be used for raster products produced over the study domain (not including circumpolar datasets).
2. To provide areal calculations from the data products we need to have the data in an equal area projection.
3. The products could range from fine spatial resolution (1 – 5m) to coarse spatial resolution (250m or more).
4. 30 m will be a central spatial resolution.
5. Users of raster data can easily download files that are 300MB in size.
The addition of the 5-meter grid, Grid C, is new in Version 2.