Online reporting systems like the Greenprint report report tool query, one at a time, a range of layers to build individual area reports. The volume of data in the Greenprint meant we could not rely on that approach - each report would take many minutes to run. Instead, we created a "fishnet" - a grid of 30-meter square polygons across the region, where each grid cell contains values for many different metrics. Creating an area report then involves selecting the correct grid cells (those within the area the user selected) and summing, averaging, or otherwise aggregating the values for each of the metrics.
Precise unit values have been assigned to the fishnet cells - data layers have not been downsampled. Not all data can be accurately reflected in the grid. Those that would double-count, exclude, or misrepresent attributes are handled outside of the fishnet. Those variables not in the fishnet are maintained in their original form. This combination of methods allows for both fast performance and accurate results. Metrics we expect to update frequently are also maintained outside of the fishnet.
Note that most data is clipped to the nine-county Bay Area, so reports that extend outside the edge of the Bay Area will be incomplete.
The product you are downloading is precisely what the online tool uses - a feature class of vector points, representing the centroids of the 30-meter fishnet grid overlaying the Bay Area. Why centroids and not the polygon grids? Because it's significantly smaller in size, and easier to use when summarizing at your own custom geographies. Note that this is still a very large dataset at 3.5 GB in size. It contains over 20 million records and 54 fields.
The download package includes a data dictionary describing all the fields in the fishnet, their units of measurement, and math needed to be performed on each in order to match the content of the Greenprint report. For those metrics that did not fit into the fishnet, the data dictionary lists those as well, along with links to their definitions and sources.
Included in the data download package:
If you're working on a project that changes its footprint frequently, or a series of many projects (dozens or even hundreds), you may want to use this data on your own desktop rather than uploading individual project shapefiles over and over again. If that does not describe your needs, we encourage you to read through this documentation before committing to running the data on your own. We estimate it will take as long as a full workday to download everything and work through how to use it on your own.
Most of the data used in the Greenprint tool are freely available online. Look at the glossary for individual data source citations and links, and please feel free to reach out to us with questions (firstname.lastname@example.org). Some datasets require a license (such as CNDDB, the California Natural Diversity Database), some were exclusively shared with the Greenprint team and are not yet available to the public (such as RAMP, the Regional Advance Mitigation Project), and some are compound datasets created by the Greenprint team (such as Important Habitat for Threatened and Endangered Vertebrates).