2005/2006 Southwest Florida Water Management District (SWFWMD) Lidar: Peace River South (including Carter Creek)

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Simple download of data files.

Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

The Peace River South and Carter Creek LiDAR Survey was acquired for the Southwest Florida Water Management

District and processed by 3001, Inc.

| Source Geospatial Form: Remote-sensing image | Type of Source Media: Digital tape media

The ABGPS, inertial measurement unit (IMU), and raw scans are collected during the LiDAR aerial survey.

The ABGPS monitors the xyz position of the sensor and the IMU monitors the orientation. During the aerial survey laser pulses

reflected from features on the ground surface are detected by the receiver optics and collected by the data logger. GPS

locations are based on data collected by receivers on the aircraft and base stations on the ground. The ground base stations

are placed no more than 35 km radius from the flight survey area.

Process date for Carter Creek is 2006.

The ABGPS, IMU, and raw scans are integrated using proprietary software developed by the Leica Geosystems

and delivered with the Leica ALS50 System. The resultant file is in a LAS binary file format. The LAS file version 1.0 format

can be easily transferred from one file format to another. It is a binary file format that maintains information specific to

the LiDAR data (return#, intensity value, xyz, etc.). The resultant points are produced in the State Plane Florida West

coordinate system, with units in feet and referenced to the NAD83 horizontal datum and NAVD88 vertical datum.

Process date for Carter Creek is 20060726.

The unedited data are classified to facilitate the application of the appropriate feature extraction

filters. A combination of proprietary filters is applied as appropriate for the production of bare earth digital terrain

models (DTMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the

feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature

extraction filters are used to produce elevation height surfaces.

Process date for Carter Creek is 20060802.

Filtered and edited data are subjected to rigorous QA/QC according to the 3001 Inc. Quality Control Plan

and procedures. Very briefly, a series of quantitative and visual procedures are employed to validate the accuracy and

consistency of the filtered and edited data. Ground control is established by 3001, Inc. and GPS-derived ground control

points (GCPs) points in various areas of dominant and prescribed land cover. These points are coded according to land cover,

surface material and ground control suitability. A suitable number of points are selected for calculation of a statistically

significant accuracy assessment as per the requirements of the National Standard for Spatial Data Accuracy. A spatial

proximity analysis is used to select edited lidar data points within a specified distance of the relevant GCPs. A search

radius decision rule is applied with consideration of terrain complexity, cumulative error and adequate sample size. Accuracy

validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation

of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA) according to Federal Geographic

Data Committee (FGDC) specifications.

Process date for Carter Creek is 20060807-20060914. Processing for Peace River South is 2005/2006.

The LiDAR mass points were delivered in American Society for Photogrammetry and Remote Sensing LAS 1.0

format. The header file for each dataset is complete as define by the LAS 1.0 specification. In addition the following fields

are included: Flight Date Julian, Year, and Class. The LAS files do not include overlap. The data was classified as follows:

Class 1 = Unclassified. This class includes vegetation, buildings, noise etc.

Class 2 = Ground

Class 3 = Water

The datasets were delivered in the Districts standard 5000' by 5000' tiling scheme. The tiles are contiguous

and do not overlap. The tiles are suitable for seamless topographic data mosaics that include no "no data" areas. The names

of the tiles are left padded with zeros as required to achieve a five character length and all files utilize the LAS file

extension. The South Peace LiDAR Survey was filtered and edited using LiDAR profiles, aerial imagery, and stereo pairs that

were created from LiDAR intensity images. The South Peace LiDAR datasets have gone through extensive QC procedures by 3001

and the Southwest Florida Water Management District. During the QC, 3001 used the following principals to guide their

filtering, editing, and QC decisions: All of the data sets were reviewed and the breaklines were created using stereo pairs

that were generated from the GeoCue LiDARgrammetry software. In addition, imagery was used during the editing / and breakline

creation processes and during the final review of the data sets. If the imagery and the LiDAR did not agree, 3001 used the

LiDAR profiles as a guide in areas where the profiles were adequate. In areas where the point density was not sufficient

enough to use as a guide, 3001 relied on the imagery and created obstruction polygons. If an area changed between the Imagery

acquisition and the LiDAR acquisition, 3001 followed the LiDAR as a guide. 3001 used the LiDAR and the imagery to create

breaklines. In some instances, the breaklines do not reflect the imagery due to a significant amount of rain during

acquisition. The following paragraph is from the South Peace metadata.

"There was significant rain fall during the acquisition of the South Peace LiDAR survey. According to the gage at the

USGS 02295637 Peace River at Zolfo Springs Florida, the gage height went from approximately 14.3 feet to 17.3 feet between

February 28, 2005 and March 2, 2005. Between March 2, 2005 and March 4, 2005 the gage fell to about 15.1 feet. The changes

in the channel are evident in the breaklines. In some areas there are sudden changes in the size of the channel as well as

the elevation of the breaklines. Due to the inconsistencies in the channel we have created obscured polygons around the

affected channels."

In areas of dense vegetation the bare-earth surface may appear rough in nature. This is due to the scarcity of points in the

area or the uneven nature of the ground. Quality Control Procedures were performed by different people and using different

methods during the project. Due to this, there may be different interpretations of the bare-earth surface in areas of dense

vegetation. The main difference in the surfaces is the amount of points that each editor removed from the profile to represent

the ground. This does not mean that either editor was incorrect in their calculations; it means that some editors were able

to describe the surface with less points. The process date for Peace River South is 2005/2006.

The process date for Carter Creek for this step is 20060921.

The NOAA Office for Coastal Management (OCM) received the files in LAS format. The files contained Lidar

intensity and elevation measurements. The data was in Florida State Plane Projection and NAVD88 vertical datum. OCM

performed the following processing to the data to make it available within the LDART Retrieval Tool (LDART):

1. The data were converted from Florida State Plane West coordinates to geographic coordinates.

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 99.

3. The LAS data were sorted by latitude and the headers were updated.