Title:
FY2007 Digital Orthophoto Metadata - North District

Publication date: July 18, 2007
Geospatial data presentation form: Mr. Sid Mosaic

Publication information:
Publication place: 11315 Corporate Boulevard, Suite 115, Orlando, FL 32817-8340
Publisher: Woolpert, Inc.

Originators:
Southwest Florida Water Management District (SWFWMD)
Mapping and GIS Section
2379 Broad Street (Mail Code GIS)
Brooksville, FL 34604-6899
352-796-7211
352-540-6018 (Fax)
8:00 am - 5:00 pm

Title:
2006 SWFWMD North District DOI Project (B089)

Publication date: July 18, 2007
Edition: Original
Geospatial data presentation form: Raster digital data MrSid

Abstract:
This data set is one component of a digital orthophoto coverage (DOI) over the Southwest Florida Water Management District (SWFWMD) North District and Polk District Project Area. This dataset is comprised of color DOI cells in a Geotiff format, at a 1-foot pixel resolution, based on the District 5,000' x 5,000' tile system. This dataset was created from source imagery acquired through the Leica ADS40/ADS51 multispectral scanners during January 26 through March 5 2007. There are a total of 6,063 cells (tiles) encompassing +/-5,437 square miles in all or parts of Alachua, Citrus, Hernando, Lake, Levy, Marion, Pasco, Polk and Sumter counties. The companion datasets to this coverage include color infrared DOI at the same pixel resolution and geographic extents as the color DOI dataset and a dataset comprised of the original imagery mosaic lines with dates of imagery acquisition in the ESRI shapefile format. The GeoTIFF format was compressed to MrSid format for distribution or is stored in ArcSDE for District use.

Process Description:
The imagery was acquired in the Winter of 2007 (see SWFWMD FY2007 Digital Orthophoto cutlines shapefile for a listing of imagery and acquisition dates) using the Leica ADS40 and ADS51 multispectral scanner. The fundamental resoltuion of the imagery was 0.9-feet over the approximate 4,920 square mile project area. The Leica ADS40 Airborne Digital Sensor delivers all digital, 12-bit data with the swath width and coverage area of a traditional film camera with up to 5-centimeter spatial resolution. The sensor is capable of simultaneous acquisition of seven bands of information: three panchromatic CCD lines capture information in views forward, nadir and backward from the aircraft, while four multispectral lines capture data in the near-infrared band. Th ADS40 utilizes the Applanix POSAV direct positioning and orientation system that is based on airborne GPS and inertial measurement unit (IMU) technology. POSAV data were reduced using the Applanix POSPAC Air software package (V4.3). All of the source imagery was processed using the Leica GPRO (V2.1) software package. This package provides the capability to perform digital image processing, aerial triangulation and image rectification. The rectified strips of imagery were then mosaicked together to form a seamless base map over the North District Project area using the OrthoVista software (version 4.1.1) by Inpho GmbH. Image tiles were then extracted using the I/RASC software package (version 8.04.00) by Z/I Imaging

For each deliverable, the individual geotiffs were loaded into a single raster mosaic in the District's enterprise SDE using ArcCatalog. The tile size is 128 with a 50% JPEG compression. Pyramids were built after all of the geotiffs were loaded using command line ArcSDE. Statistics was built using the software TOAD on all raster tables in SDE. The District conducted QC on the deliverables (see Logical Consistency Report). Once completed and all the deliverables were accepted by the District, all geotiffs were loaded into a single mosaic file. For the District's GIS Data Distribution site, MrSid mosaics are created using the GeoExpress software by LizardTech. They are compressed at a ratio of 20:1 from GeoTiff files. These mosaics then have projection files (.aux) created for viewing with ArcGIS. The .aux files are created from the Raster Georeference Enabler (RAGE) tool developed by 3001.

Logic:
SWFWMD QC The imagery data layer stored in the District's enterprise database is opened in ArcMap. The District's LiDAR project grid is also added. The imagery is scanned at 1:6,000 looking at each LiDAR grid cell individually. If a problem is found, then a point shapefile is created and a point in the location of the problem is added. Comments are added to the shapefile in an attribute field about the problem and a bitmap is created displaying the area with the problem. Each bitmap includes: comments added to the shapefile, grid cell number, date, initials of the QC staff, and whether the image is natural color or color infrared. After all of the grids have been scanned, the imagery is drawn to the full extent. The overall color balance and offset is checked. Possible problems that are reviewed include: color balance between cut lines over land, offsets over 8 feet, missing data, anomalies, and overall color balance.

Purpose:
The DOI was developed to support the DISTRICT's regulatory, land management and acquisition, planning, engineering, and habitat restoration projects