Submersed Aquatic Vegetation community multi-year data from the Sacramento - San Joaquin Delta in California

Since 2007, field data have been collected in the Sacramento - San Joaquin Delta in northern California for the purpose of training and validating invasive species maps derived from remote sensing imagery over the Delta. The field crew collected submersed aquatic vegetation (SAV) species location data. For each point they noted attributes such as species name(s), location, cover estimates, and patch size. In addition, a thatching rake tethered to a rope was thrown off the side of the boat and pulled back out of the water; Secchi depth was measured using a Secchi disk and depth to the SAV mat was estimated by the field crew. Points were collected in patches larger than 9 square meters (3 m x 3 m). Point locations were measured using high precision (sub-meter accuracy) Trimble DGPS units (Trimble Navigation Limited, Sunnyvale, California) with Wide Area Augmentation System (WAAS) differential correction. All data points were exported as ArcGIS shapefiles and projected to UTM Zone 10N, Datum WGS-84 however this dataset includes the Latitude and Longitude of each point in decimal degrees. The spatial and attribute data quality was checked by examining photos of the data points and confirming the identify of the documented species.