The Polygon tab

Select the Polygon tab from the BioBase trip viewer to view the GIS Polygon tool. GIS polygon tool allows you to trace areas of interest on the map and generate area analysis and statistics.

These statistics include area, depth and water volume statistics, as well as aquatic vegetation cover and biovolume statistics.

Creating a polygon

You can create a new polygon or assign the same polygon to multiple trips that can be accessed by all users in an organization.

To create a polygon on the map, use the Create new polygon button found in the Polygon tab. Click on the map to set a polygon vertex and double click to set the last vertex and close the polygon.

Saving a polygon

the Polygon tab to generate the polygon area analysis and statistics data. Polygons are grouped by waterbody.

When the polygon is calculated and applied to the selected trip, you can review the polygon area analysis and statistics data listed on the Analysis Polygon Metadata table. These data are based on kriging interpolated raster grid values.

Note: Once a polygon is saved, it cannot be edited.

Note: Polygon "templates" that intersect a waterbody are saved in that particular waterbody and available for all members in an organization who have a BioBase account. If a polygon does not intersect a waterbody (e.g., an "orphan" polygon) the template will be listed in all waterbodies in a users account. Polygon templates are not automatically "applied" to all trips, and thus if a user wishes to apply a previously created template to a new trip or merge they must select the "save" icon to generate the statistics

Saving the analysis polygon metadata

You can save the polygon area analysis and statistics data listed on the Analysis Polygon Metadata table simply by selecting the data in the polygon window, then copying (Ctrl + C) and pasting (Ctrl + V) the data into a spreadsheet.

Deleting a polygon

Note: Only polygon owners or Organization Data Managers can delete polygons.

To delete a polygon, select the polygon and click the Delete button found beside the polygon name. Deleting a polygon from a selected trip will also delete the polygon from other associated trips.

Note: Once a polygon is deleted, it cannot be undone.

Note: Polygon statistic generation requires a background application to run and can sometimes take minutes to complete depending on lake size and amount of data in the trip/merge. You can only create and analyze one polygon at a time. If many users are using the feature at the same time, you may need to wait to save. Watch the alerts in the upper right part of your screen and click the Save icon periodically until the service is available.

Exporting a polygon

You can export any polygon as a GIS shapefile associated to the selected trip. To export, use the Download Analysis Polygons button. The button is available when you click the Export Selected Polygons button found in the Polygon tab.

The exported polygon contains shapefiles and other polygon area analysis and statistics data associated to the selected trip.

The shapefiles can be uploaded and analyzed in any GIS software that supports the *.shp format. The shapefiles can also be converted to *.gpx trails that can be used in your Lowrance/Simrad MFD

Note: BioBasemaps.com does not offer user support for various file conversions.

Reusing existing polygon

You can reuse any existing polygons listed in the Template Polygons. Any available polygon in the list may be a system generated or created by someone else.

To reuse an existing polygon, select the polygon from the list and click the Apply and Calculate button found beside the polygon name. The polygon will then be calculated and applied to your selected trip.

Example 1: The image shown below is an example of how the polygon GIS tool is used around a hypothetical area targeted for treatment with aquatic herbicides.

Care was taken not to include extrapolated areas outside of the track because submersed vegetation growth between the boat track (red line) and shore was not verified during the data collection.
Example 2: The image shown below is an example of a polygon statistics from an area where only a small proportion of the trip was sampled.

You should interpret generated statistics in cases like these with extreme caution because statistics are based on only a very small sampled area and may not be representative of the remaining polygon area.