BISON provides access to georeferenced (those with latitude and longitude coordinates) and non-georeferenced data describing the occurrence or presence of terrestrial and aquatic species recorded or collected by a person (or instrument) at a specific time in the United States and its Territories (American Samoa, Guam, the Federated States of Micronesia, the Republic of Palau, the Republic of Marshall Islands, the Northern Mariana Islands, Puerto Rico, the U.S. Virgin Islands, and U.S. Minor Outlying Islands). We refer to these data in general terms as 'species occurrence data'. The species occurrence data that are available through BISON have been contributed by various Federal and State agencies, universities, and non-profit organizations either directly to BISON or indirectly through their participation in the Global Biodiversity Information Facility (GBIF). Each record in a species occurrence dataset available in BISON will typically consist of a scientific name (genus and specific epithet), a date, and one or more geographic references such as a state name, county name, and/or decimal latitude and longitude coordinates. In addition to these typical data fields, species occurrence datasets often include many other data fields that describe each species occurrence event in more detail.

Most research on biological organisms in the wild involves recording or collecting evidence of an occurrence of a species by a person (or instrument) at a particular place and time: We refer to these data in general terms as 'species occurrence data'. Regardless of the initial reason why the species occurrence was recorded somewhere, the knowledge that it was actually at a specific place at a specific time is extremely useful in many areas of science. For example, these occurrence records are instrumental in tracking the spread of invasive species, the decline of threatened species, and the movement of ranges in response to climate change or other environmental factors. Species occurrence data is used as baseline data for modeling and analysis, in ecological research, and in the management of natural resources.

Each record in a species occurrence dataset available in BISON will typically consist of a scientific name (genus and specific epithet), a date, and one or more geographic references such as a state name, county name, and/or decimal latitude and longitude coordinates. In addition to these typical data fields, species occurrence datasets often include many other data fields that describe each species occurrence event in more detail.

BISON can accommodate some or all of the following data fields:

Associated Media - the URL link to media files associated with the species occurrence record
Associated References - A hyperlinked resource or reference associated with the occurrence, such as a sound or video file, pdf publication, or an html landing page with additional associated URLs.
Basis of Record - the type of species occurrence or evidence upon which it is based. Basis of Record values include the following:

• fossil - petrified evidence in geological time
• germplasm - living tissue from which new organisms can be grown
• literature - assertion in a scientific publication
• living - the organism is kept at the given location
• observation - record of a free-living organismal occurrence that does not produce a specimen or germplasm
• specimen - the organism or a part of it has been collected and preserved in a formal collection
• unknown - the nature of the record is obscure

BISON ID (or ID)- a unique identifier assigned to the species occurrence record during the upload process, which may or may not be persistent
Calculated FIPS - the standardized 5-digit numeric geographic Federal Information Processing Standard or FIPS code for the U.S. State/Territory-County name combination
Calculated State Name - the standardized U.S. State or Territory name computed based on the Calculated FIPS value
Catalog Number - A unique (preferably persistent) alpha-numeric code or key for each record (row) in a dataset
Centroid - a text string indicating that the latitude and longitude coordinates represent the central point of a polygon, and describing the polygon type e.g. "7.5 min Grid"
Clean Provided Scientific Name - the standardized Latin scientific term for the organism. Most commonly but not always a binomial name. In BISON, it does not include taxonomic author. Mapped whenever possible to the Integrated Taxonomic Information System (ITIS), https://www.itis.gov/)
Collector - The name(s) of people, group(s), or organization(s) responsible for recording the original species occurrence
Collector Number - an identifier given to the species occurrence record by the collector at the time it was recorded
Common Names - the vernacular (or common) name(s) for the species
Coordinate Precision - a decimal representation of the exactness of the latitude and longitude coordinates
Coordinate Uncertainty - the horizontal distance (in meters) from the latitude and longitude coordinates, describing the smallest circle containing the whole of the species occurrence location
County - the U.S. county, parish, or borough name in which the species occurrence is located (may be designated by the collector or by the most recent county name based on the latitudinal and longitudinal coordinates)
General Comments - a free text field for additional pertinent information associated with the species occurrence that isn't appropriate for other available data fields.
Geodetic Datum - the ellipsoid, geodetic datum, or spatial reference system (SRS) upon which the geographic coordinates given in the Latitude and Longitude fields are based
ID (or bisonID)- a unique identifier assigned to the species occurrence record during the upload process, which may or may not be persistent
ISO Country Code - the standardized two-letter geographic country code of the species occurrence according to ISO 3166-1 alpha-2
ITIS Common Name - the organism's vernacular name according to the Integrated Taxonomic Information System (ITIS, https://www.itis.gov/)
ITIS TSN - the ITIS unique, persistent, Taxonomic Serial Number (TSN) associated with the Clean Provided Scientific Name
Latitude - the decimal angular distance of a point north (+) or south (-) of the earth's equator for the location of the species occurrence (in BISON, up to 6 decimal places)
Longitude - the decimal angular distance of a point east (+) or west (-) of the earth's Greenwich UK Prime Meridian for the location of the species occurrence (in BISON, up to 6 decimal places)
Occurrence Date - the date on which the species sighting or collection event was observed or recorded, in the ISO 8601 standard format YYYY-MM-DD
Occurrence URL - a URL link to the occurrence record (if available elsewhere on the Internet)
Provided Common Name - the original, uncorrected vernacular name(s) of the species, retained as it was provided in the original, raw dataset
Provided County Name - the original, uncorrected U.S. County, Parish, or organized Borough name retained as it was provided in the original, raw dataset
Provided FIPS - the original, uncorrected 5-digit numeric geographic Federal Information Processing Standards of FIPS code for the U.S. State/Territory-County name combination, retained as it was provided in the original, raw dataset
Provided Kingdom - the original, uncorrected taxonomic Kingdom of the species, retained as it was provided in the original, raw dataset
Provided Scientific Name - the original, uncorrected scientific name retained as it was provided in the original, raw dataset
Provided State Name - the original, uncorrected U.S. State or Territory name as it was provided in the original, raw dataset
Provider - name of the data provider
Provider ID - a unique, non-persistent integer identifier for the data provider
Provider URL - the URL link to the data provider or source of the species occurrence data
Resource - the name, acronym, or code, identifying the service, group, collection or dataset from which the record was derived
Resource ID - a unique, integer identifier for the Resource or dataset
Resource URL - a URL link to the collection or dataset from which the record was derived
Scientific Name - the Latin taxonomic name, usually a combination of genus and specific epithet for the species
Thumb URL - the URL link to a small or thumbnail sized version of a larger media file associated with the species occurrence record
Valid Accepted Scientific Name - the standardized current valid or accepted scientific name of the species according to ITIS, that is taxonomically linked to the Clean Provided Scientific Name (the latter may or may not be a valid or accepted scientific name for the species)
Verbatim Depth - the original, uncorrected description of the depth below the local surface retained as it was provided in the original, raw dataset
Verbatim Elevation - the original, uncorrected description of the elevation (altitude, usually above sea level) retained as it was provided in the original, raw dataset
Year - the year in which the species occurrence or collection event was recorded, in the ISO standard format YYYY (see ISO 8601).

Any data field label that begins with 'As Provided' or ‘Provided’ is one that contains the original, uncorrected data, retained as it was provided to us in the raw dataset. Data fields whose labels begin with 'calculated' contain a cleaned and/or standardized version of the original data.

When the information in provided and calculated data fields differs, it may indicate a difference in format or accuracy, and not necessarily an error, in the data. These differences commonly occur in species occurrence data when the contents of data fields are misspelled, abbreviated, old (such as old U.S. counties that have since been renamed), or include additional characters that can inhibit database indexing. Calculated fields in BISON often reflect the conversion of data such as latitude and longitude coordinates or a date to a standard format e.g. reformatting coordinates from a degrees-minutes-seconds format to a decimal degrees format. This standardization of the data can improve data indexing and search functionality.

In BISON, calculated data do not replace original data, they are only appended to datasets in specifically designated data fields and are not intended to change the ‘story’ communicated by the original dataset.

No, BISON does not include observations of the absence of species (or species absence data). And the absence of georeferenced or non-georeferenced species occurrence (presence) data in BISON does not prove or indicate the absence of that species in the United States and its Territories (American Samoa, Guam, the Federated States of Micronesia, the Republic of Palau, the Republic of Marshall Islands, the Northern Mariana Islands, Puerto Rico, the U.S. Virgin Islands, and U.S. Minor Outlying Islands). In order for species absence data to be useful, much more information about the sampling methods used to collect the data must be known and incorporated into any interpretation of the data in a statistically defensible way.

No, but lists of all of the species currently represented in BISON are available through the links below. The species are listed alphabetically by scientific name and each name links to a dynamically generated map of occurrences for that species. Use the unique URLs provided for each species scientific name to insert or reference these species occurrence maps in your own Web sites.

BISON is sponsored and developed by the Core Science Analytics and Synthesis (CSAS) program of the United States Geological Survey (USGS). The USGS is also the U.S. Node of the Global Biodiversity Information Facility (GBIF)and benefits in terms of the data and aggregation services provided by GBIF, funded in part by contributions from multiple Federal agencies. BISON also greatly benefits from the contributions of more than 300 participating data providers including many Federal agencies, universities, and non-profit organizations.

The species occurrence data that are available through BISON have been contributed by various Federal and State agencies, universities, and non-profit organizations either directly to BISON or indirectly through their participation in the Global Biodiversity Information Facility (GBIF). BISON is a product of the United States Geological Survey (USGS) (the U.S. Node of GBIF), and thus works closely and shares data with GBIF. As data providers contribute data directly to BISON, they become part of the network of more than 300 data providers whose data are submitted regularly to GBIF. In turn, as U.S. data are added directly to GBIF, their data also become available through BISON. There is a time lag between updates, so a search of GBIF and BISON may not always yield the same results. While data in BISON conform to the Darwin Core standard, data providers are ultimately responsible for the quality, scope, and resolution of the data that they provide.

Use the following format to cite data retrieved from BISON:

[Data Provider or Owner name]. [Resource or dataset name] published by [Data Provider name, address or affiliation(s)] (Accessed through Biodiversity Information Serving Our Nation (BISON), https://bison.usgs.gov, YYYY-MM-DD)

For example:
Field Museum of Natural History. U.S. Bird Occurrences published by Field Museum of Natural History, Museum of Vertebrate Zoology, University of Washington Burke Museum, and University of Turku (Accessed through Biodiversity Information Serving Our Nation (BISON), https://bison.usgs.gov, 2014-02-22)

Or

Gordon, J. U.S. Bird Occurrences published by Field Museum of Natural History, Museum of Vertebrate Zoology, University of Washington Burke Museum, and University of Turku (Accessed through Biodiversity Information Serving Our Nation (BISON), https://bison.usgs.gov, 2014-02-22)

This citation format is also included on the About page, and in the Data Use Agreement that displays during the first data download in each BISON Web session.

BISON provides access to species occurrence data recorded or collected at locations within the coastal boundaries of the United States and its Territories (American Samoa, Guam, the Federated States of Micronesia, the Republic of Palau, the Republic of Marshall Islands, the Northern Mariana Islands, Puerto Rico, the U.S. Virgin Islands, and U.S. Minor Outlying Islands). However some of these data are contributed by data providers who are not themselves located in the U.S. or its Territories.

Some data in BISON contain only partial geographic information. For example, some records may have a state designated, but no county or latitude and longitude coordinates. These non-georeferenced records cannot be displayed as dots on the map; however, they can be viewed in the List view accessed from the upper right corner of the map display and in data downloaded from BISON in CSV format. Note that data downloaded from BISON in KML or zipped shapefile bundle (ZIP) formats will include only georeferenced records.

The absence of data for any species in BISON does not prove or indicate the absence of that species from the U.S. or its Territories. Thus data available through BISON should not be considered comprehensive in terms of species' geographic ranges or distributions.

There are three ways to search for all species occurrence data within a geographic area in the BISON Map view:

1. Search by state and/or county: After the map displays the default BISON State Heatmap layer (see Layers pull-out tab on the right side of the map), click on any state and choose either the Show Counties or the Download link from the pop-up information box (you may need to enable pop-ups in your browser to see the pop-up information box). If you choose the Show Counties link, the BISON County Heatmap layer will be displayed for the selected state. Click on any county and choose either the Show Occurrences or the Download link from the pop-up information box.
2. Search by rectangular bounding box: After the map displays, click on either the Define BISON Search BBOX tool icon (a tan square on a gray (inactive) or orange (active) background, in the top right corner of the map) or on the Zoom In tool icon (a plus sign inside a magnifying glass over a red square on a gray (inactive) or orange (active) background) and click and drag the box boundaries over the area of interest on the map (up to a maximum of 100,000 square kilometers). This will initiate a search for species occurrence data within the selected area and the map will also zoom to the selected area. Use the Zoom In tool and/or the 'Move around the map' tool (a white hand on a gray (inactive) or orange (active) background) to move the map around and zoom in to the area of interest.
3. Search by Polygon tool: After the map displays, click on the Define BISON Search Polygon tool icon (a tan polygon on a gray (inactive) or orange (active) background, near the top right corner of the map). Then click along the edges and corners of the area of interest on the map (up to a maximum of 100,000 square kilometers) and close the polygon shape with a double click. This will initiate a search for species occurrence data within the selected area. Use the Zoom In tool ( a plus sign inside a magnifying glass over a red square on a gray (inactive) or orange (active) background) and/or the 'Move around the map' tool (a white hand on a gray (inactive) or orange (active) background) to move the map around and zoom in to the area of interest.

Within any of these three geographic area search techniques, the total number of records that matched your search criteria is displayed on the left side, immediately above the map. The number of georeferenced records that matched your search criteria is displayed in the gray bar immediately beneath the text indicating the total number of records.

Click the List link (above the upper right corner of the map) to view a paginated list of the search results. To switch back to the map view, click on the Map link (above the upper right corner of the map).

Refine Your Search Results
Click on the Refine Your Search link (above the upper right corner of the map) to refine your search by selecting one or more options from the Basis of Record, Provider, State, Higher Taxa, ,Year Range, and Centroid categories. When using the Refine Your Search feature, at least one Basis of Record and at least one Provider must be specified (all are selected as the default). Click on the Update Search Results button in the Refine Your Search panel to apply your selected options or click on the Hide Search Details button to close the Refine Your Search panel.

BISON provides access to species occurrence data from any time period that can be represented in a four digit year (YYYY) or year, month, day (YYYY-MM-DD) format (see ISO 8601). A four digit year is BISON's minimum requirement for a species occurrence date or date upon which a species' presence was observed, recorded or collected. BISON does not currently accommodate geologic time units. However BISON does provide access to species occurrence data that are based on fossil evidence. In this case, the occurrence date usually represents the date upon which the fossil was found and/or the fossil-based observation of the species' presence or occurrence was recorded.

Data available through BISON are not limited to any specific taxon or organism. BISON does not however include occurrence data for all species known to currently or to have historically occurred in the U.S. and its Territories. The absence of data for any species in BISON does not prove or indicate the absence of that species from the U.S. or its Territories. Thus data available through BISON should not be considered comprehensive in terms of taxonomic coverage.

Each data provider is responsible for choosing what scientific names they will use to refer to species in their datasets. BISON uses the Integrated Taxonomic Information System (ITIS) as its taxonomic authority for scientific names and has incorporated an ITIS index into its search functionality. ITIS is extremely rich in U.S. taxa and fully complete for most high-profile taxonomic groups. When a scientific or common name search is conducted in BISON with the ITIS enabled search checkbox selected (this is the default setting), BISON compares the name entered by the user with those in ITIS, and based on that comparison, retrieves all species occurrence records that include an exact match, plus any records for taxonomic synonyms and their children.

Sometimes very different organisms (i.e. a plant and an animal) can have the same scientific or common name and are only distinguishable by their taxonomic name authors and higher taxonomic groupings e.g. the genus Ficus authored by Linnaeus is a group of plant species but it is also a genus of snail species authored by Röding. If the user has chosen an ambiguous name like this for their search, they will be asked to choose from a list of scientific names in order to clarify their search criteria e.g. did they mean to search for the plant or the animal known by that name? The ITIS index and disambiguation capability allows BISON to provide comprehensive search results for individual species and for entire hierarchical taxonomic groups (families, orders, etc.), while also being able to include related, old, invalid/not accepted or ambiguous names.

If a user chooses a scientific or common name for their search that is not currently included in the ITIS index, or if the ITIS enabled search checkbox is not selected, BISON will perform an 'exact-match' search, retrieving only those species occurrence data that include exactly that scientific or common name.

BISON can be searched by entering a species scientific name or common name (or by geographic area - see question 11). Select the type of search you wish to perform from the pick-list to the left of the search box (ITIS Enabled/Not Enabled; scientific or common name). BISON uses the Integrated Taxonomic Information System (ITIS) (our taxonomic authority) to improve the quality of search results (see question 14) so we recommend choosing one of the ITIS Enabled search options. As you start typing a species scientific or common name into the search box, a dynamically generated type-ahead menu will display, offering suggested names. If you see the species name that you are interested in listed in the type-ahead menu, select it by clicking on the name and your search will automatically start (no need to click the Search button). If you do not see the type-ahead menu or the name you are interested in does not appear in it, finish typing the name in the search box and click the Search button. If you use an ambiguous species name for your search, you may be asked to choose a more specific name in order to complete the search.

BISON includes georeferenced (those with latitude and longitude coordinates) and non-georeferenced data. Georeferenced data can be displayed as dots on the map or as records in the List view accessed through the List link above the upper right corner of the map. Non-georeferenced data can only be displayed as records in the List view.

The total number of records that match your search criteria is displayed on the left side, immediately above the map. The number of georeferenced records that match your search criteria is displayed in the gray bar immediately beneath the text indicating the total number of records.

Click the List link (above the upper right corner of the map) to view a paginated list of the search results. To switch back to the Map view, click on the Map link (next to the List link).

If your search results include more than 5,000 georeferenced species occurrences, the default BISON State Heatmap layer displays, on which the number of species occurrences in each state is represented by a range of light to dark color shades (explained in the Legend pull-out tab on the left side of the map). Click on any state to view information on the number of occurrences in that state in a pop-up information box (you may need to enable pop-ups in your browser to see the pop-up information box). The pop-up information box also includes a Show Counties link and a Download link. Click on the Show Counties link to display the BISON County Heatmap for the selected state or on the Download link to download the species occurrence data for that entire state.

If your search results include less than 5,000 georeferenced species occurrences, a map displays on which the species occurrences are represented by different colored dots (explained in the Legend pull-out tab on the left side of the map). A single dot may represent multiple species occurrence records. Click on an individual dot to view details about the record(s) it represents. Change the display back to a Heatmap style by selecting the State and/or County Heatmap layers from the BISON Layers section of the Layers tab and modifying their opacity as needed.

Refine Your Search Results
Click on the Refine Your Search link (above the upper right corner of the map) to refine your search by selecting one or more options from the Basis of Record, Provider, State, Higher Taxa, Year Range, and Centroid categories. Choose individual options by clicking on their corresponding checkboxes or use the Check All and Uncheck All links below each category. Selecting some options may result in the display of subcategories or different categories in the panel e.g. multiple resources available from a provider; counties within a state. When using the Refine Your Search feature, at least one Basis of Record and at least one Provider must be specified (all are selected as the default). Click on the Update Search Results button in the Refine Your Search panel to apply your selected options or click on the Hide Search Details button to close the Refine Your Search panel. The Refine Your Search panel will not close until either the Hide Search Details button or the Update Search Results button is clicked.

BISON includes georeferenced data (those with latitude and longitude coordinates) and non-georeferenced data. Georeferenced data can be displayed as dots in the Map view or as records in the List view. Non-georeferenced data can only be displayed in the List view. There are three ways to download data (search results) from BISON:

1. Download both georeferenced and non-georeferenced data as a batch using the data download tool (a downward-pointing white arrow inside a gray (inactive) or green (active) circle, in the upper right corner of the map),
2. Download a single georeferenced occurrence point by clicking on a single dot on the map and choosing the download option for a single record, and
3. Download all of the georeferenced and non-georeferenced data for a particular state or county by clicking on the state or county (with the View Feature Information tool active) and choosing the Download link.

Batch downloads in CSV format (see question 18) will include both georeferenced and non-georeferenced species occurrence records returned by the selected search criteria. Data downloaded from BISON in KML or zipped shapefile bundle (ZIP) formats will include only georeferenced records. Note that large datasets (>3000 records) may take several minutes to process. In such cases, the user will be notified and given the option to have the file emailed to them.

A Data Use Agreement displays once during the first data download in each BISON Web session. You must accept the Data Use Agreement before any data download can be completed.

No. Data are available for download from BISON in three different formats: comma separated values (CSV), Google Earth Keyhole Markup Language (KML), and as a zipped Shapefile bundle (ZIP). The download format that you choose will determine what software you can use to open a downloaded file and interact with the data. Data downloaded from BISON in CSV format will include both georeferenced (those with decimal latitude and longitude coordinates) and non-georeferenced records while data downloaded in KML format or as a zipped shapefile bundle (ZIP) will include only georeferenced records.

Common spreadsheet (e.g., MSExcel) and basic text (e.g., Notepad) reading software may be used to open data downloaded from BISON in CSV format. Mapping and data visualization software such as Google Earth and ArcGIS can be used to display and manipulate georeferenced data.

For mapping purposes, note that some data providers do not report their datum to us, so we assume the WGS84 datum (and Web Mercator Projection for Web display) for the BISON Web Map Service (see question 20). But when mapping georeferenced data downloaded from BISON use the EPSG-4326 Map Projection for the WGS84 datum.

Yes. A REST (Representational State Transfer) API (Application Programming Interface) is available for application developers. The API is documented here.

We assume the WGS84 datum (and Web Mercator projection for Web display) for the BISON Web Map Service. For the WGS84 datum use the EPSG-4326 Map Projection. But when mapping georeferenced data downloaded from BISON use the EPSG-4326 Map Projection for the WGS84 datum.

BISON is optimized for the most recent versions of Firefox and Internet Explorer. It will also display in Chrome, Opera, and Safari.

The system is best viewed at a screen resolution of 1024 x 768 pixels or higher. In the browser settings, make sure that pop-up windows are not blocked. This can be done via Options in the Tools menu of Firefox, or via Internet Options in the Tools menu of Internet Explorer.

The BISON search capability involves use of the Search and Reset buttons, and the Refine Your Search link. The Search button enables the user to initiate a search based on the name of a species that they have typed into the search box. The Reset button refreshes the map display, returning it to the default BISON State Heatmap layer and clearing any search criteria or results from view.

Refine Your Search Results
Click on the Refine Your Search link (above the upper right corner of the map) to refine your search by selecting one or more options from the Basis of Record, Provider, State, Higher Taxa, Year Range, and Centroid categories. Choose individual options by clicking on their corresponding checkboxes or use the Check All and Uncheck All links below each category. Selecting some options may result in the display of subcategories or different categories in the panel e.g. multiple resources available from a provider; counties within a state. When using the Refine Your Search feature, at least one Basis of Record and at least one Provider must be specified (all are selected as the default). Click on the Update Search Results button in the Refine Your Search panel to apply your selected options or click on the Hide Search Details button to discard your selections and close the Refine Your Search panel. The Refine Your Search panel will not close until either the Hide Search Details button or the Update Search Results button is clicked.

Map Tools
Hover the cursor over each of the map tools (in the upper right corner of the map) to see pop-up text that identifies and explains the function of each tool (you may need to enable pop-ups in your browser if you do not see the pop-up text). To activate and use a map tool, click on it and then click on the map. With the exception of the Data Download tool (a downward-pointing white arrow inside a gray (inactive) or green (active) circle), an active tool or one that is currently in use will have an orange colored background. Inactive tools have a gray colored background.

Map Tools, from left to right:

The Incremental Pan and Zoom tool (a set of 4 white arrows above a plus, minus, and globe symbol on a blue background, in the upper left corner of the map) enable the user to shift the map up, down, left, and right (arrows); and zoom in (plus symbol), zoom out (minus symbol), and to the global extent or a view of all continents (globe symbol).

The Data Download tool (a downward-pointing white arrow inside a gray (inactive) or green (active) circle) initiates a download of the selected search results. It is activated when your search results include 15 million records or less. Click on this tool to initiate the data download process (see question 17 for more information about downloading data from BISON).

The View Feature Information tool (the letter 'i' inside a blue map pin on a gray (inactive) or orange (active) background) is selected or active by default. It enables the user to click on states or counties in the BISON State or County Heatmap layers or on individual dots in the BISON Occurrence Layer (described in the Layers pull-out tab on the right side of the map) to view information about species occurrence data associated with them (you may need to enable pop-ups in your browser to see these pop-up information boxes).

The Zoom In tool (a plus sign inside a magnifying glass over a red square on a gray (inactive) or orange (active) background) enables the user to click and/or draw a rectangular bounding box and zoom in on the map to enlarge an area of interest, centered on the cursor or bounding box. The View Feature Information tool is then activated. Either continue to click on the Zoom In tool to continue zooming in to your area of interest or click on the View Feature Information tool and then on the map to display a pop-up information box containing either a Show Counties (for a State Heatmap layer) link or a Show Occurrences link (for a County Heatmap layer), and a Download link; or click on a dot on the map to display a pop-up information box containing a Show Details link and a Download link for each record represented by the dot.

The Define BISON Search BBOX (bounding box) tool (a tan square on a gray (inactive) or orange (active) background in the top right corner of the map) enables the user to select and search for species occurrence data within a particular area of the map defined by a rectangle shape. Click on the Define BISON Search BBOX tool and then click and drag the box boundaries over the area of interest on the map (up to a maximum of 100,000 square kilometers). This will initiate a search for species occurrence data within the selected area and the map will also zoom to the selected area.

The Define BISON Search Polygon tool (a tan polygon on a gray (inactive) or orange (active) background) enables the user to select and search for species occurrence data within a particular area of the map defined by a polygon shape. Click on the Define BISON Search Polygon tool and then click along the edges and corners of the area of interest on the map (up to a maximum of 100,000 square kilometers) and close the polygon shape with a double click. This will initiate a search for species occurrence data within the selected area.

The 'Move around the map' tool (a white hand on a gray (inactive) or orange (active) background) enables the user to move the map display in any direction, and remains active until you choose another tool.

The BISON map view includes three main links: Refine Your Search, Map, and List above the top right corner of the map. The Refine Your Search link displays a panel that enables the user to narrow the search by selecting one or more options from the following categories: Basis of Record, Provider, State, County, Year Range, Higher Taxa, and Centroid (see question 16). The List link displays both georeferenced (those with latitude and longitude coordinates) and non-georeferenced search results in a paginated list while the Map link displays only georeferenced records as dots on the map.

If state and county search criteria are selected, additional links display inside square brackets in the line of text above the left corner of the map e.g. [show all counties], [show all states]. Clicking on these links will display the results in either the BISON County Heatmap or the BISON State Heatmap layers.

The Legend pull-out tab (on the left side of the map) provides a key to the colors used in each of the BISON State Heatmap, County Heatmap, and Occurrence Layer map layers. Click on the Legend pull-out tab to show or hide it from view (the Legend pull-out tab will not close until the user closes it). Darker shades in the BISON State Heatmap and County Heatmap layers indicate higher numbers of occurrences. Different colored dots in the BISON Occurrence Layer indicate the evidence on which each species occurrence record is based e.g. observation, specimen, fossil, literature, living, or unknown; and whether or not the dot represents latitude and longitude coordinates for a centroid (or center) of a polygon such as a county. The content of the Legend pull-out tab changes to reflect changes in search results.

The Layers pull-out tab (on the right side of the map) lists over 50 map layers that are available to augment the map display with additional geospatial information. Click the Layers pull-out tab to show or hide it from view (the Layers pull-out tab will not close until the user closes it). Click on any of the map layer categories to expand and collapse them. Select or deselect individual map layers by clicking on their corresponding radio options or checkboxes. The selected layers will be added to the map (some map layers may take some time to display depending on their size and on your internet connection). For a selected layer, clicking on the layer name will expand and collapse an opacity slider and a legend or key to that layer's colors and features. The small blue bar at the left of each layer links to its source or to metadata about the layer.

BISON provides access to over 50 map layers to augment the display of your search results (click on the Layers pull-out tab on the right side of the map to view them). Many of them are provided by third-party sources, whose services may not always be available. We will do our best to ensure that all the BISON map layers are available to you, but there may be brief periods of time during which a selected dynamically-served layer may not render. We have added checks in our code to determine if the base layers (USGS Base Map and USGS Vector Map) are unavailable, and when this is true alternative base layers are chosen. If the base layers stop working while BISON is in use, reload the page and the alternative base layers will be displayed. If you encounter a map layer that is not functioning, clear your browser's cache, and try the layer again. If the layer is still not functioning, please let us know by sending an email to bison@usgs.gov