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OCM Partners, 2022: 2004 Southwest Florida Water Management District Lidar: Sarasota District, https://www.fisheries.noaa.gov/inport/item/50029.

Item Identification

Title: 2004 Southwest Florida Water Management District Lidar: Sarasota District
Short Name: swfwmd_sarasota_m63_metadata
Status: Completed
Publication Date: 2005-05-10
Abstract:

This metadata record describes the ortho & lidar mapping of Sarasota County, FL. The mapping consists of lidar data

collected using a Leica ALS-40 Lidar Sensor, contour generation, and production of natural color orthophotography with a 30-cm

GSD using imagery collected with a Leica ADS-40 Aerial Digital Camera. This topographic survey for Sarasota County covers 572

square miles and was acquired in two lift acquisitions. Lift 1 was on Feb 28 2004 and lift 2 was on Mar 4, 2004. The original

lidar had gaps in the coverage and the areas were flown on May 15, 2004. Lidar data acquired with 2 meter nominal post spacing.

Original contact information:

Contact Name: Steve Dicks

Contact Org: Southwest Florida Water Management District (SWFWMD)

Phone: 352-796-7211

Purpose:

The purpose of this mapping project is to create and deliver digital terrain models (DTM), capable of generating one-foot

contours and to produce orthophotography at a 200' scale.

Notes:

10673

Supplemental Information:

The Report of Topographic Survey for Sarasota County may be viewed at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/63/supplemental/index.html

Keywords

Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
elevation
UNCONTROLLED
EDI Thesaurus Aerial Photography
EDI Thesaurus Bathymetry/Topography
EDI Thesaurus Contours
EDI Thesaurus Digital Orthophotography
EDI Thesaurus Digital Terrain Model (DTM)
EDI Thesaurus LIDAR

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: Unknown
Distribution Liability:

Any conclusions drawn for the analysis of this information are not the responsibility of the Office for Coastal Management or its partners.

Support Roles

Data Steward

CC ID: 687667
Date Effective From: 2005-05-10
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 687669
Date Effective From: 2005-05-10
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Metadata Contact

CC ID: 687670
Date Effective From: 2005-05-10
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 687668
Date Effective From: 2005-05-10
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Publication Date

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1139782
W° Bound: -82.6558
E° Bound: -82.0403
N° Bound: 27.4754
S° Bound: 26.9309

Extent Group 1 / Time Frame 1

CC ID: 1139779
Time Frame Type: Discrete
Start: 2004-02-28

Extent Group 1 / Time Frame 2

CC ID: 1139780
Time Frame Type: Discrete
Start: 2004-03-04

Extent Group 1 / Time Frame 3

CC ID: 1139781
Time Frame Type: Discrete
Start: 2004-05-15

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;

Data Access Constraints:

None

Data Use Constraints:

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of

this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a

full awareness of its limitations.

Distribution Information

Distribution 1

CC ID: 742682
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=63
Distributor:
File Name: Customized Download
Description:

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

Distribution 2

CC ID: 742683
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/63/index.html
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 742685
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 742686
URL: https://coast.noaa.gov
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 687687
Activity Date/Time: 2017-03-20
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 687686
Activity Date/Time: 2017-11-14
Description:

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.

Activity Log 3

CC ID: 718631
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 742684
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Data Quality

Accuracy:

The generated contours were NOT produced to be fully compliant with NSSDA accuracy standards for 2'

contours. Contours were generated from lidar DTM as is without the benefit of photogrammetric breakline support. Lidar elevation

data meets National Map Accuracy Standards. The digital orthophotography meets national mapping accuracy standards for 200 scale

product.

Horizontal Positional Accuracy:

The digital orthophotos fully comply with NMAS standards for production of orthophotos at

a horizontal natural ratio of 1 to 2,400 with a ground pixel resolution of 1 foot.

Tested 1.1 m (3.6-feet) horizontal accuracy at the 95% confidence level.

Vertical Positional Accuracy:

The digital elevation model is fully compliant with National Standard for Spatial Data

Accuracy (NSSDA) published by the Federal Geographic Data Committee (FGDC) in 1998. The NSSDA uses root-mean-square error

(RMSE) to estimate positional accuracy. RMSE is the square root of the average of the set of squared differences between

data set coordinate values and coordinate values from an independent source of higher accuracy for identical points.

Accuracy is reported in ground distances at the 95% confidence level. Accuracy reported at the 95% confidence level means

that 95% of the positions in the data set will have an error with respect to true ground position that is equal to or smaller

than the reported accuracy value. The reported accuracy value reflects all uncertainties, including those introduced by geodetic

control coordinates, compilation, and final computation of ground coordinate values in the product. The intended vertical

accuracy of this project is 17.98 cm (0.59-feet) (95% confidence level) vertical.

RMSE=9.144 cm (0.3-feet) for unobscured ground points, not tested.

Completeness Measure:

Cloud Cover: 0

Completeness Report:

The following software is used for validation of the

1. Aerotriangulation - ISTAR Processing

2. DTM data - Z/I Imaging SSK

3. Digital Orthophotography - Z/I Imaging OrthoPro

Conceptual Consistency:

Compliance with the accuracy standard was ensured by the placement of GPS ground control prior to the

acquisition of aerial photography. The following checks were performed.

1. The ground control and airborne GPS data stream were validated through a fully analytical bundle aerotriangulation adjustment.

The residuals of the adjustment met the required standards for accuracy which are 1 part in 10,000 of the flying height for the

horizontal position (X and Y) and 1 part in 9,000 or better of the flying height in elevation (Z).

2. The DTM (Digital Terrain Model) data were checked against the project control. The technician visited and confirmed the accuracy

of the project mass points during initial processing.

3. Digital orthophotography was validated through an inspection of edge matching and visual inspection for image quality.

Lineage

Sources

Digital Aerial Photography of Sarasota County, FL

CC ID: 1139769
Publish Date: 2004-02-08
Extent Type: Range
Extent Start Date/Time: 2004-02-03
Extent End Date/Time: 2004-02-08
Scale Denominator: 14400
Source Contribution:

The digital aerial photographic mission was composed of a total of 2 lifts of flight lines. Photography

was obtained at an altitude of 9,450 feet above mean terrain. Digital photography was recorded in conjunction with airborne GPS;

the stationary GPS receiver was positioned over a control point located at the airport. Recorded digital imagery was shipped

via external hard drive to the production facility for processing.

| Source Geospatial Form: Profile | Type of Source Media: Firewire Drive

Lidar Acquisition of Sarasota County, FL

CC ID: 1139770
Publish Date: 2004-03-04
Extent Type: Range
Extent Start Date/Time: 2004-02-28
Extent End Date/Time: 2004-03-04
Source Contribution:

The lidar acquisition for Sarasota County consisted of 2 lifts of flight lines acquired in 2 sorties using

the Leica ALS40 sensor. The data was acquired at a flying height of 6,000 feet AMT with a scan rate of 13 Hz and a 25 degree

field of view. Approximately 3.04 billion raw lidar points were collected at a nominal 2 meter post spacing.

| Source Geospatial Form: Profile | Type of Source Media: Firewire Drive

Report of Survey - SWFWMD, Sarasota County, FL

CC ID: 1139771
Publish Date: 2004-04-21
Extent Type: Discrete
Extent Start Date/Time: 2004-07-20
Scale Denominator: 1200
Source Contribution:

Kevin Chappell, a Florida PSM, under contract to EarthData International established 15 photo identifiable

ground control after aerial imagery acquisition. The points were surveyed using GPS for both vertical and horizontal coordinate

values. Ground control references Florida West State Plane NAD83, NAVD88 both in Meters.

| Source Geospatial Form: Diagram | Type of Source Media: Electronic mail system

Process Steps

Process Step 1

CC ID: 1139772
Description:

New ground control was established to control and orient the photography, and included only photo-identifiable

features. The ground control network and airborne GPS data was integrated into a rigid network through the completion of a fully

analytical bundle aerotriangulation adjustment.

1. The digital aerial photo data was ingested into the ISTAR processing system by uploading the data from portable hard drives.

2. The coverage of the imagery was checked for gaps and a directory tree structure for the project was established on one

of the workstations. This project was then accessed by other workstations through the network. The criteria used for

establishment of the directory structure and file naming conventions accessed through the network avoid confusion or

errors due to inconsistencies in digital data. The project area was reviewed against the client-approved boundary.

The technician verified that the datum and units of measurement for the supplied control were consistent with the project

requirements.

3. The photogrammetric technician performed an automatic triangulation of the data using the ISTAR processing system.

The aerotriangulation adjustment merged the airborne GPS, IMU, and ground control data into a project-wide network.

4. While ground control points (GCPs) were used, reliance on the GPS-/IMU-derived orientation parameters required significantly

fewer GCPs than are typically used in aerotriangulation.

5. The adjustment was performed for each sortie and then multiple sorties were merged to produce a project-wide adjustment.

6. The aerotriangulation component of the ISTAR suite utilized the airborne GPS as a separate control source and held the

IMU (Inertial Measurement Unit) parameters rigidly.

7. The accuracy of the final solution was verified by running the final adjustment, placing no constraints on any quality control

points. The RMSE values for these points must fall within the tolerances above for the solution to be acceptable.

Process Date/Time: 2004-09-30 00:00:00

Process Step 2

CC ID: 1139773
Description:

EarthData has developed a unique method for processing lidar data to identify and remove elevation points

falling on vegetation, buildings, and other aboveground structures. The algorithms for filtering data were utilized within

EarthData's proprietary software and commercial software written by TerraSolid. This software suite of tools provides efficient

processing for small to large-scale, projects and has been incorporated into ISO 9001 compliant production work flows. The

following is a step-by-step breakdown of the process.

1. Using the lidar data set provided by EarthData, the technician performs calibrations on the data set.

2. Using the lidar data set provided by EarthData, the technician performed a visual inspection of the data to verify that the

flight lines overlap correctly. The technician also verified that there were no voids, and that the data covered the project

limits. The technician then selected a series of areas from the data set and inspected them where adjacent flight lines

overlapped. These overlapping areas were merged and a process which utilizes 3-D Analyst and EarthData's proprietary software

was run to detect and color code the differences in elevation values and profiles. The technician reviewed these plots and

located the areas that contained systematic errors or distortions that were introduced by the lidar sensor.

3. Systematic distortions highlighted in step 2 were removed and the data was re-inspected. Corrections and adjustments can

involve the application of angular deflection or compensation for curvature of the ground surface that can be introduced

by crossing from one type of land cover to another.

4. The lidar data for each flight line was trimmed in batch for the removal of the overlap areas between flight lines. The data

was checked against a control network to ensure that vertical requirements were maintained. Conversion to the client-specified

datum and projections were then completed. The lidar flight line data sets were then segmented into adjoining tiles for batch

processing and data management.

5. The initial batch-processing run removed 95% of points falling on vegetation. The algorithm also removed the points that

fell on the edge of hard features such as structures, elevated roadways and bridges.

6. The operator interactively processed the data using lidar editing tools. During this final phase the operator generated

a TIN based on a desired thematic layer to evaluate the automated classification performed in step 5. This allowed the

operator to quickly re-classify points from one layer to another and recreate the TIN surface to see the effects of edits.

Geo-referenced images were toggled on or off to aid the operator in identifying problem areas. The data was also examined

with an automated profiling tool to aid the operator in the reclassification.

7. The data were separated into a bare-earth DEM. A grid-fill program was used to fill data voids caused by reflective objects

such as buildings and vegetation. The final DEM was written to an ASCII XYZ and LAS format.

8. The reflective surface data were also delivered in ASCII XYZ and LAS format.

9. Final TIN files are created and delivered.

Process Date/Time: 2004-08-17 00:00:00

Process Step 3

CC ID: 1139774
Description:

This process describes the method used to compile hydro-breaklines to support H&H modeling efforts. The

technical method used to produce hydro-breaklines for use in this project only included water features and they should not

be confused with traditional stereo-graphic or field survey derived breaklines. Watershed Concepts and EarthData utilized

techniques developed for FEMA flood map modernization projects to synthesize 3D break lines using digital orthophotos and

lidar data.

1. For larger streams (widths greater than 50 feet), breaklines were collected on the left and right water edge lines. The

2D lines defining streams and other water bodies were manually digitized into ArcView shape file format from the ADS-40

digital imagery. Flat water bodies such as ponds were collected by examining points near the edge of water, were a low

point could be quickly identified. This allowed the operators to draw an even-elevation breakline at that elevation

around the water body's perimeter.

2. A bounding polygon, created from the edge of bank lines, was used to remove all lidar points from within the channels

of streams and bodies of water. This step ensures that the lidar bare-earth point files match the breaklines.

3. The elevation component of the 3D streamlines (breaklines) was derived from the lowest adjacent bare earth lidar point

and was adjusted to ensure that the streams flow downstream. The best elevation that can be derived for the 3D streamlines

will be the water surface elevation on the date that the lidar data was acquired.

4. Automatic processes assigned elevations to the vertices of the centerline based on surrounding lidar points. The lines

were then smoothed to ensure a continuous downhill flow. Edge-of-bank vertices were adjusted vertically to match the

stream centerline vertices.

5. The new 3D lines were then viewed in profile to correct any anomalous vertices or remove errant points from the lidar DTM,

which cause unrealistic "spikes" or "dips" in the breaklines.

6. For this project, hydro breaklines were generated in the matter described above for all streams and water bodies.

a) A 2000 to identify any quality issues.

b) An automated routine was run to check the data for closure of water bodies.

c) An evaporation routine was run to remove lidar points from water bodies.

d) A final routine was run to check the generate TINs for anomalies including outside township/range boundary and elevation

extremes.

7. New TINs were then created from the remaining lidar points and newly created breaklines.

8. The breakline data set was then put into an ESRI shape file format

9. The 1 foot contours were generated in Microstation (using 2 foot specifications) with an overlay software package called

TerraSolid. Within TerraSolid, the module Terramodeler was utilized to first create the tin and then a color relief was

created to view for any irregularities before the contour generator was run. The contours were checked for accuracy over

the DTM and then the Index contours were annotated. At this point the technician identified any areas of heavy tree

coverage by collecting obscure shapes. Any contours that were found within these shapes are coded as obscure. The data

set was viewed over the orthos before the final conversion. The contours were then converted to Arc/Info where final

QC AMLs were run to verify that no contours were crossing. The contours were delivered in ESRI .shp format as a merged

file.

Due to the nature of the breaklines collected in accordance with FEMA guidelines, the contours do not meet any specified

accuracy requirement and are delivered as is.

Process Date/Time: 2005-04-15 00:00:00

Process Step 4

CC ID: 1139775
Description:

The digital orthophotography was produced in natural color at a natural ratio of 1 to 2,400 with a 1 ft

pixel resolution. A step-by-step breakdown of the digital orthophoto production process follows.

1. Digital image swath files were visually checked for image quality on the networked ISTAR processing farm.

2. The digital image files were loaded onto the digital orthophoto production workstation. The following information was then

loaded onto the workstation. - The camera parameters and flight line direction - Ground control and pass point locations -

The exterior orientation parameters from the aerotriangulation process - ASCII file containing the corner coordinates of the

orthophotos - The digital elevation model. - Project-specific requirements such as final tile size and resolution.

-Orientation parameters developed from the aerotriangulation solution. A coordinate transformation based on the camera

calibration fiducial coordinates was then undertaken. This transformation allowed the conversion of every measured element

of the images to a sample/line location. Each pixel in an image was then referenced by sample and line (its horizontal and

vertical position) and matched to project control.

3. The newly re-sected image was visually checked for pixel drop-out and/or other artifacts that may degrade the final orthophoto

image.

4. DTM data were imported and written to the correct subdirectory on disk.

5. The DTM file was re-inspected for missing or erroneous data points.

6. A complete differential rectification was carried out using a cubic convolution algorithm that removed image displacement

due to topographic relief, tip and tilt of the aircraft at the moment of exposure, and radial distortion within the camera.

Each final orthophoto was produced at a natural scale of 1 to 2,400 with a 1ft pixel resolution. At this point in the

process, the digital orthophotos covered the full aerial frame.

7. Each digital orthophoto image was visually checked for accuracy on the workstation screen. Selected control points

(control panels or photo-identifiable points) that are visible on the original film were visited on the screen, and the

X and Y coordinates of the location of the panel or photo-identifiable point were measured. This information was

cross-referenced with the X and Y information provided by the original ground survey. If the orthophoto did not meet or

exceed NMAS standards, the rectification was regenerated. The digital orthophotos were then edge-matched using proprietary

software that runs in Z/I Imaging OrthoPro software package. Adjoining images were displayed in alternating colors of red

and cyan. In areas of exact overlap, the image appears in gray-scale rendition. Offsets were colored red or cyan, depending

on the angle of displacement. The operator panned down each overlap line at a map scale to inspect the overlap area. Any

offset exceeding accuracy standards was re-rectified after the DTM and AT information was rechecked.

Process Date/Time: 2004-09-15 00:00:00

Process Step 5

CC ID: 1139776
Description:

8. Once the orthos were inspected and approved for accuracy, the files were copied to the network and downloaded by the ortho

finishing department. This production unit was charged with radiometrically correcting the orthophotos prior to completing

the mosaicking and clipping of the final tiles. The image processing technician performed a histogram analysis of several

images that contained different land forms (urban, agricultural, forested, etc.) and established a histogram that best

preserves detail in highlight and shadow areas. EarthData International has developed a proprietary piece of software

called "Image Dodging." This radiometric correction algorithm was utilized in batch and interactive modes. Used in this

fashion, this routine eliminated density changes due to sun angle and changes in flight direction. A block of images were

processed through image dodging, in batch mode and displayed using Z/I Imaging OrthoPro software. At this point the images

have been balanced internally, but there are global differences in color and brightness that were adjusted interactively.

The technician assigned correction values for each orthophoto then displayed the corrected files to assess the effectiveness

of the adjustment. This process was repeated until the match was considered near seamless. The files then were returned to

digital orthophoto production to mosaic the images.

9. The processed images were mosaicked using the Z/I Imaging software. The mosaic lines were set up interactively by the

technician and were placed in areas that avoided buildings, bridges, elevated roadways, or other features that would

highlight the mosaic lines. File names were assigned.

10. The finishing department performed final visual checks for orthophoto image quality. The images were inspected using

Adobe Photoshop, which enabled the technician to remove dust and lint from the image files interactively. Depending on the

size and location of the flaw, Photoshop provided several tools to remove the flaw. Interactive removal of dust was

accomplished at high magnification so that repairs are invisible. 11. The final orthophoto images were written out into

GeoTIFF format.

Process Date/Time: 2004-09-15 00:00:00

Process Step 6

CC ID: 1139777
Description:

The NOAA Office for Coastal Management (OCM) received the files in LAS format. The files contained Lidar 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 Geoid03.

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

Process Date/Time: 2008-01-25 00:00:00

Catalog Details

Catalog Item ID: 50029
GUID: gov.noaa.nmfs.inport:50029
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:23+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16