In the 1920s and 1930s Albert Everett Wieslander and several others explored much of California’s wilderness sampling vegetation, taking photographs, collecting specimens, and drawing detailed maps of what they found. These data represent a valuable resource for comparative and conservation ecology. The data are now fully digitized and made available through the Ecoengine.
For more information regarding this projects and its rediscovery, see vtm.berkeley.edu . An extended version of the site including tools for convenient data exploration will be released in August 2014.
The collection consists of three parts:
Contemporary retakes of the historic photos are also part of the collection and we will start a campaign for more re-shots in the future.
The Photos taken by Wieslander’s team during the VTM project are a subset of the /api/photos/ resource and can be accessed by querying /api/photos/?collection_code=vtm. All query parameters documented for this resource can be applied to the VTM photo collection.
If a historic photo has one or more contemporary re-shots (or vice versa)
the property internal_reference
will hold a list of internal links pointing to the associated resources:
{
"record": "CalPhotos:0000+0000+0513+1990",
"internal_reference": [
{
"url": "http://dev-ecoengine.berkeley.edu/api/photos/CalPhotos%3A5555%2B5555%2B0000%2B2687/"
}
]
}
To detect all VTM retakes query /api/photos/?collection_code=vtm&min_date=1980-01-01.
Another option is the use of the search engine: /api/photos/?q=retake. In doing so, it might become necessary to
thoroughly check the returns because such a query triggers a full text search and could return also
records that have contain the word “retake” in other contexts.
It is currently somewhat harder to select all historic photos that have a retake. The best strategy would be to query for retakes as described above and then select the historic photos using follow-up queries.
Some photos have associated species observations. Those were generated when the curators at CalPhoto explicitly extracted
species names from the photographer’s notes. Observations record associated with VTM data can be detected by
querying the /api/observations/ resource using the collection_code “vtm”: /api/observations/?collection_code=vtm.
Species entries derived from photos will have the observation_type “photo record”.
The Wieslander Vegetation Features (/api/vtmveg/) resource provides the digitized version of polygons that were drawn on topological maps and labeled with the dominant species in that area. The resource is somewhat similar to /api/checklists/ in regard to the fact that a geographic feature is associated with an observations list. However it has some specific attributes.
List View
GET /api/vtmveg/¶Detail View
GET /api/vtmveg/(record)¶GET /api/vtmveg/(url_escaped_record)¶Tile Template
GET /tiles/vtmveg/{z}/{x}/{y}.png¶The tile template provides pre-rendered and cached tiles. The legend needs to be added/published.
The field whr provides a crosswalk from Wieslander’s dominant species field to the Wildlife Habitat Relationships, Vegetation Type (WHRTYPE). More information
and linked resources see www.fs.usda.gov/detail/r5/landmanagement/resourcemanagement/?cid=fsbdev3_048103.
The field mcv contains a similar crosswalk to the CNPS’ Manual of California Vegetation, for more resources see
www.cnps.org/cnps/vegetation/manual.php
The geographical query methods as described in Query Parameters Working Across Resources can be applied.
Warning
Known data problems:
- Some features have terms associated that are not species. In some cases this entries generated invalid observation entries.
- Some identifications are ambiguous, or incorrectly over-specified. For example redwood was collected with one single abbreviation which was (incorrectly) transcribed as Sequoia sempervirens in the Sierra Nevada.
Please let you know if you find additional problems. Thank you.
Plot surveys take a detailed inventory of species and abundance in sample plots representing a landscape or vegetation. The Wieslander team studied over 17,000 plots between 1920 and 1939. They recorded tree and brush species, tree size and brush distribution.
Within the Ecoengine this data is represented by three endpoints: plots, plot trees, and plot brushes, a structure that represents the original data most effectively.
List View
GET /api/vtmplots/¶Detail View
GET /api/vtmplots/(record)/¶The plot resources contain all properties that are associated with the plot such as the geometry, the collection data, the location description, soil characteristics etc.
It also contains a list of species connecting to observations records via linked resources. These links that connect a species with a particular plot have additional attributes and are stored in the VTM plots trees and the VTM plots brushes resources which can be independently used as a starting point for analysis:
List View
GET /api/vtmplot_trees/¶Detail View
GET /api/vtmplot_tress/(link_id)¶Attributes
List View
GET /api/vtmplot_brushes/¶Detail View
GET /api/vtmplot_brushes/(link_id)¶Attributes
Warning
The VTM plots data need some further clean-up. Species names are not always clean and contain additional comments such as ‘LITTER’, ‘BARREN, etc. In some cases identification seems to be ambiguous. The resource will improve as Maggy Kelly’s team is actively working on the data. If you plan research using this data, please contact us.