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Florida Statewide Base Digital Orthophotography Program Requirements
Florida Statewide Base Digital Orthophotography Group
August 1, 2013
3 ABBREVIATIONS / DEFINITIONS
4 PROJECT AREA
5 ORTHOPHOTO SPECIFICATIONS
5.2 Image Spatial Resolution
5.3 Horizontal and Vertical Datum
5.4 Horizontal Accuracy
5.5 Digital Elevation Model
6 IMAGE ACQUISITION
6.1 Ground Control
6.2 Flight Season
6.3 Image Quality
6.4 Historical Images
7 ORTHOPHOTO DELIVERABLES
7.1 File Formats and Image Types
7.3 Image Cutline Feature Class
7.4 Survey Report
8 ORTHOPHOTO PROJECT SCHEDULE
TABLE 1 – SURVEY CHECK POINTS FIELD PROPERTIES
ATTACHMENT A – GROUND CONTROL SURVEY REQUIREMENTS
ATTACHMENT B – REQUIRED TIFF AND GEOTIFF TAGS AND KEYS AND SAMPLE VALUES........... 16 ATTACHMENT C – METADATA TEMPLATES
Page 2 of 44 Florida Statewide Base Digital Orthophoto Program Requirements August 1, 2013 1 INTRODUCTION Since 1972, Florida Statutes have stipulated cooperation between USGS, FDOT, and the state Water Management Districts to facilitate statewide topographic mapping efforts.
Currently part of this is being done through the Florida Statewide Base Digital Orthophotography Program (FSBDOP) supported by partnerships and agreements between several state, federal, and local agencies represented by the Florida Digital Base Orthophotography Group. The current FSBDOP consists of statewide orthophotography coverage on a three year cycle for Florida with a ground sample distance of one foot.
This document defines the minimum requirements for providing digital orthophotography products for inclusion into the FSBDOP. All final data will be considered a public record as defined by applicable Florida Statutes.
When a contract is awarded and before any work begins, the consultant will contact the Florida Department of Transportation Surveying and Mapping Office to request a Photographic Designation (PD) number to be assigned to the project. This number will be by FDOT to track the project through the quality assurance process before being submitted to USGS, and shall be referenced in all correspondence and project deliverables.
Any products created from oblique aerial imagery acquired during the Orthophotography project imagery collection are beyond the scope of this document.
All work performed must be in accordance with the Minimum Technical Standards, Rule Chapter 5J-17, F.A.C., pursuant to Chapter 472, Florida Statutes. Unless otherwise stated herein the orthophotography products will be in accordance with the “U.S. Geological Survey Base Orthoimagery Specification (draft)”, dated August 23, 2010.
3 ABBREVIATIONS / DEFINITIONSASPRS – American Society for Photogrammetry & Remote Sensing CADD - Computer Aided Design & Drafting •
FIPS – Federal Information Processing Standards • FSBDOG – Florida Statewide Base Digital Orthophoto Group • FSBDOP – Florida Statewide Base Digital Orthophoto Program •
Page 3 of 44 Florida Statewide Base Digital Orthophoto Program Requirements August 1, 2013 LiDAR - Light Detection and Ranging LAS – A binary file standard supported by ASPRS for storing point location and • attribute information primarily used for LiDAR data.
• NSSDA – National Standard for Spatial Data Accuracy • Orthophotograph – A photographic copy, prepared from a perspective photograph, Orthophoto – same as Orthophotograph • in which the displacements of images due to tilt and relief have been removed.
• (Source: American Congress on Surveying and Mapping and the American Society of Civil Engineers. Definitions of Surveying and Associated Terms. Library of Congress Catalogue Card Number 72-76807. Washington 1972, 1978.
Orthophotomosaic – An assembly of orthophotographs forming a uniform-scale mosaic. (Source: American Congress on Surveying and Mapping and the American • Society of Civil Engineers. Definitions of Surveying and Associated Terms. Library of Congress Catalogue Card Number 72-76807. Washington 1972, 1978.
Orthorectification – A special case of image resampling whereby the effects of image perspective and relief displacement are removed so that the resulting •
orthoimage has uniformly scaled pixels, resembling a planimetric map. (Source:
American Society for Photogrammetry and Remote Sensing Manual of Photogrammetry Fifth Edition, 2004, page 963) Photogrammetry - The science or art of obtaining reliable measurements by photography. (Source: American Congress on Surveying and Mapping and the • American Society of Civil Engineers. Definitions of Surveying and Associated Terms.
Library of Congress Catalogue Card Number 72-76807. Washington 1972, 1978.
RMSE – Root Mean Square Error USft – United States Survey Feet •
4 PROJECT AREA The Agency will provide an outline of the project area to be mapped along with a collection of 5000 by 5000 foot tiles (cells) for this area using the FSBDOP predefined grid. This will serve as the final uniform tiling scheme for the seamless Orthophoto mosaic and topographic data deliverables.
5 ORTHOPHOTO SPECIFICATIONS
5.1 Sensor All imagery shall be collected using a digital aerial sensor with current USGS type certification. The sensor must also have a documented bore-sight calibration performed within six months of image acquisition.
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5.2 Image Spatial Resolution All original imagery will have a resolution between 0.5 feet and 1.06 feet. The Consultant will deliver images that have been re-sampled to 1.0 foot Ground Sample Distance (GSD) as defined in section 7: Orthophoto Deliverables.
5.3 Horizontal and Vertical Datum Unless otherwise requested the Orthophotography and other topographic products shall be referenced to the latest NGS realization of the North American Datum of 1983 (NAD83).
The map projection referenced shall be to the appropriate Florida State Plane Coordinate System in units of US Survey Feet.
Orthophotography and other topographic products shall be referenced to the North American Vertical Datum of 1988 (NAVD 88), in units of US Survey Feet.
5.4 Horizontal Accuracy Horizontal accuracy of the final Orthophotography product shall be determined using well defined photo identifiable check points. Computed local horizontal accuracy shall meet or exceed 5.06’ at the 95% confidence interval as specified in the FGDC “Geospatial Positioning Accuracy Standards, Part 3: National Standard for Spatial Data Accuracy”. A minimum of thirty (30) independent image checkpoints within the project area will be used for verification. Check points will be distributed throughout the dataset.
5.5 Digital Elevation Model A Digital Elevation Model adequate to support accuracy specifications identified for this project must be created to accurately orthorectify photographic imagery.
When available the Agency will provide DEM(s) or LiDAR data if available from past projects. The Consultant is responsible for evaluating the accuracy of the DEMs, and when necessary processing additional break lines necessary to accurately orthorectify photographic imagery.
The Consultant will submit information in the final survey report and metadata which documents the source, enhancements made, and final accuracy of the DEMs utilized for the Orthophoto mapping project.
Additionally, if LiDAR data is acquired as part of the project, the classified scan data must be provided in LAS file format as per ASPRS LAS Specification 1.2 with associated metadata.
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6 IMAGE ACQUISITION
6.1 Ground Control Sufficient ground control shall be used to support one foot Ground Sample Distance (GSD) spatial resolution Orthophoto mapping for the project. All newly established ground control as well as the check points necessary to meet the requirements of the Florida Digital Base Orthophotography Group document “Ground Control Requirements for Florida Statewide Base Digital Orthophotography Program”, dated September 1, 2011 see Attachment A.
The Consultant will coordinate with Agency staff in planning ground control surveys and methodology used for all horizontal and vertical control surveys.
6.2 Flight Season The specified flight season will be from October 1st through March 15th. To the greatest extent possible imagery should be obtained prior to January 30th. Imagery collected outside of this flight season will require written approval from contracting agency.
6.3 Image Quality All images will be obtained under cloud free conditions and will be free of obscuring haze, smoke or other atmospheric conditions. Radiometric and color balancing of the imagery is described in Section 7: Orthophoto Deliverables. All images must be collected with a sun angle no less than 30°.
Imagery shall be acquired at a density in the “high-rise” urban areas such that all road networks are clearly visible and that buildings show no signs of excessive tilt or lean.
6.4 Historical Images To maintain consistency between images collected during different years, historical examples of imagery shall be reviewed. If applicable color balancing should be performed that is consistent with previous FSBDOP county imagery.
7 ORTHOPHOTO DELIVERABLESAll deliverables will be the property of the Contracting Agency and are considered public record. Written permission from the Agency must be obtained to release data to any party prior to final publication. The Consultant will deliver only the Ortho-rectified color infrared and natural color imagery. Stereoscopic panchromatic imagery will be collected but not delivered unless specifically requested by the Agency. The Consultant will keep a copy of the original data for a period of five (5) years and must contact the Agency before destroying the data.
Page 6 of 44 Florida Statewide Base Digital Orthophoto Program Requirements August 1, 2013 The Consultant will document all data deliveries with an itemized transmittal letter.
7.1 File Formats and Image Types Clarity and quality of the imagery is of the highest importance. Imagery will be delivered as uncompressed GeoTIFF images with valid projection header information. Refer to
ATTACHMENT B – REQUIRED TIFF AND GEOTIFF TAGS AND KEYS AND SAMPLE VALUES fordetails. One GeoTIFF file per 5000 x 5000 foot tile is required.
a) Natural Color Imagery – The natural color, RGB, bands will be color balanced across the entire study area to the greatest extent possible to allow viewing of the image tiles as a visually seamless mosaic. Care should be taken during radiometric processing to avoid loss of detail in shadows and overexposure on bright surfaces such as bare ground and light colored building roofs.
b) Color Infrared Imagery – The color infrared bands will be radiometrically processed in a manner that preserves original image characteristics to the greatest extent practical. Systematic radiometric corrections to reduce sun angle and sensor variations are desired. Corrections for seasonal variations in ground cover are not to be done, however, care should be taken to ensure appropriate coloration of different vegetation types (e.g. deciduous, evergreen, etc.) is evident.
All orthoimages will be delivered according to the tiling scheme defined in Section 4:
Project Area. Tiles will be contiguous and non-overlapping and will be suitable for creating a seamless image mosaic that includes no data void cells or gaps. Tile naming convention is
The following examples represent the three color variations of the same Orthophoto image tile that was acquired during the 2013– 2014 flying season.
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7.2 Metadata A metadata file must be delivered for each GeoTIFF image file, the DEM used for OrthoPhoto production, and the cutline feature class in an ArcCatalog compatible XML format. Templates for each deliverable that requires metadata are found in ATTACHMENT C – METADATA TEMPLATES. The templates are also available in an XML file delivered under separate cover.
Metadata must be compliant with the Federal Geographic Data Committee's (FGDC) Content Standard for Spatial Metadata. All metadata must pass through the USGS metadata parser at http://geo-nsdi.er.usgs.gov/validation/ with no errors.
Metadata and the image collection date(s) must apply to each individual tile. The image Collection Date(s) field must be populated.
7.3 Image Cutline Feature Class The Consultant will include a file “ProjectName_Cutlines” in ESRI Shape file format, containing a feature class of non-overlapping polygons with no data voids for the project area. Each polygon will delineate image capture dates used to seam together photographs for the production of orthophotography.
The feature class should conform to project boundary, and must have one date field named FLIGHTDATE that identifies the date the imagery was collected. The FLIGHTDATE attribute field should be populated as YYYYMMDD. Metadata must accompany the image cutline feature class.
7.4 Survey Report The Consultant Professional Surveyor and Mapper (PSM) will prepare a survey report that documents all processes and is compliant with relevant Minimal Technical Standards for Professional Surveying and Mapping done in Florida. The Report of Orthophotography
Survey that shall at a minimum include the following items: