| 2006 Southwest Florida Water Management District (SWFWMD) Lidar: Upper Myakka District |
| EarthData International collected ALS-50-derived LiDAR over Upper Myakka Florida with
a one-meter post spacing. The period of collection was between 3 October and 12 October
2006. This data set falls in Manatee County. The collection was performed by EarthData
Aviation, using a Leica ALS-50 LiDAR system, including an inertial measuring unit
(IMU) and a dual frequency GPS receiver. This project required six lifts of flight
lines to be collected. The product generated consisted of LiDAR bare earth elevation
models in LAS format. This data set is one component of a digital terrain model (DTM)
for the Southwest Florida Water Management District’s FY2005 Digital LiDAR Project
(H048), encompassing approximately 291 square miles across Manatee County. The 2005
LiDAR dataset is comprised of 3-D mass points delivered in the LAS file format based
on the District’s 5,000’ by 5,000’ grid (325 cells). The other DTM component is 2-D
and 3-D breakline features in the ESRI ArcGIS Personal Geodatabase format. In accordance
with the 2005 SWFWMD Topographic Database Design, the following breakline closed water
bodies (lakes, reservoirs, etc) as 3-D polygons; linear hydrographic features (streams,
canals, swales, embankments, etc) as 3-D breaklines; coastal shorelines as 3-D linear
features; edge of pavement road features as 3-D breaklines; soft features (ridges,
valleys, etc.) as 3-D breaklines; obscured vegetation polygons as 2-D polygons; overpasses
and bridges as 3-D breaklines; 1-foot contours for visualization purposes; and island
features as 3-D polygons. Breakline features were captured to develop a hydrologically
correct DTM. Contours (1-foot) were generated from the DTM that meet the National
Map Accuracy Standards for 2-foot contours (FEMA specifications). Bare earth LiDAR
mass point data display a vertical accuracy of at least 0.3-feet root mean square
error (RMSE) in open unobscured areas.
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