Original planimetric features were derived from 2014 imagery, with a horizontal positional accuracy that shall not exceed 0.38-meters NSSDA 95% confidence (0.22-meters Root Mean Squared (RMSE) Error XY (0.15 meter RMSE X or Y), suitable for 40-scale planimetrics. All data was compiled using softcopy photogrammetric methods and map compilation was conducted under the direct supervision of an ASPRS Certified Photogrammetrist. Map compilation methods used must ensure that the final deliverable will meet the project's accuracy requirements.

About the 2020 data acquisition project:

Update features in an existing planimetric dataset, and collect some new additional feature classes, from imagery acquired in the spring of 2020, with a horizontal positional accuracy that shall not exceed 0.38-meters NSSDA 95% confidence (0.22-meters Root Mean Squared (RMSE) Error XY (0.15-meter RMSE X or Y), suitable for 40-scale Planimetrics.

Imagery Bands: 4-band (true color & near infrared)

Acceptable Window: Spring 2020, generally thought to be from February 1, 2020 and continue through April 30, 2020.

Acquisition Conditions: Leaf off, snow free, free from clouds, smoke, haze, light streaks, flooding (streams/rivers in banks), and excessive soil moisture.

Sun angle: Greater than 35 degrees over entire project. Minimal shadows, generally between 10am and 2pm.

Resolution: 7.5 cm Ground Sample Distance (pixel resolution)

Integrated into the Town of Sandwich GIS 10/5/2022.

Last Town of Sandwich update: 10/5/2022.