Cumberland County 2001

Identification Information

Citation Information

Originator	GlobeXplorer, Maine Library of Geographic Information (MLGI), Maine Office of Geographic Information Systems (MEGIS)(comp.)
Publication Date	200307
Title	Cumberland County 2001
Edition	200104
Series Name	CITIPIX Ortho-rectified Digital Images (ODI)
Issue Identification	2001
Publication Place	Augusta ME
Publisher	Maine Office of Geographic Information Systems (MEGIS)
Other Citation Details	1:1200 (MEGIS) ORTHO_HF consists of 906 tiles of high resolution, 24-bit color aerial photography. These GLOBEXPLORER CITIPIX digital images have a pixel resolution (or ground sample distance) of 1/2 foot, are precision geo-referenced and ortho-rectified, and accurate for 1"=100' mapping applications. Flown in April 2001, from Portland to Auburn ME the ortho-rectified digital imagery covers all of Cumberland County and part of Androscoggin County, Maine.
Online Linkage	http://megis.maine.gov/maps/

Abstract

ORTHO_HF contains high resolution 24-bit color CITIPIX Ortho-rectified Digital Images (ODIs) from GLOBEXPLORER. These digital images result from ortho-rectification and mosaicking of scanned color aerial photographs. Each pixel represents a planimetric square 1/2 foot on a side on the ground. Digital file features include high quality ground-level georeferencing, derived from accurate positioning and geometric corrections, and provide a digital photographic map suitable for applications requiring a 1:1200 National Map Accuracy Standard (NMAS). Based on the CITIPIX nation-wide standard for urban aerial coverage, georeference and distribution, CITIPIX ODIs serve the GIS industry, state and local governments as well as private sector, supplying 6-inch (15-cm) ground pixel size map-accurate continuous digital photographic coverage.

Purpose

Based on the CITIPIX nation-wide standard for urban aerial coverage, georeference and distribution, CITIPIX ODIs serve the GIS industry, state and local governments as well as private sector, supplying 6-inch (15-cm) ground pixel size map-accurate continuous digital photographic coverage.Information in this document on the CITIPIX ODIs presented in ORTHO_HF was drawn from: GlobeXplorer. 2003. CITIPIX Ortho-rectified Digital Image (ODI) Product Description. March 2003, Walnut Creek, CA. CITIPIX is a trademarked product of GlobeXplorer. For more information about GlobeXplorer see http://www.globexplore.org/citipix.html.

Supplemental Information

ORTHO_HF is available from Maine GIS as a Web Mapping Service (WMS) and is included in the Aerial Photography Viewer located on the maps page of the MEGIS website - http://megis.maine.gov/maps/The image names of the MrSID files were created so that the first 3 digits in the name increase by one from west to east. The last 4 digits increase by one from south to north. Images in the southwest location will always have the lowest numbered name and images in the northeast will always have the highest numbered name. A file index with the same names is also available in ArcSDE and for download in the Maine GIS Internet Data Catalog.

Time Period of Content

Calendar Date	200104
Currentness Reference	flight date

Status

Progress	Complete
Maintenance and Update Frequency	Unknown

Bounding Coordinates

West Bounding Coordinate	-70.84727
East Bounding Coordinate	-69.86047
North Bounding Coordinate	44.17948
South Bounding Coordinate	43.46049

Keywords

Theme	imageryBaseMapsEarthCover (ISO Keyword Thesaurus)
Theme	aerial photograph, ortho-rectified digital image, color imagery 24-bit, ground sample distance 1/2 foot (Maine GIS Thesaurus-Theme)
Place	Maine, United States (Maine GIS Thesaurus-Place)
Stratum	land surface, radiance or imagery (GCMD Parameter Keyword)

Access Constraints

none

Use Constraints

none

Contact Organization

(MEGIS) Maine Office of Geographic Information Systems

Contact Person

GIS Coordinator

Contact Position

GIS Coordinator

Address Type

mailing address

Address

State House Station 174

City

Augusta

State or Province

Postal Code

04333-0174

Country

USA

Contact Voice Telephone

207 624-7700

Contact Facsimile Telephone

207 287-3842

Hours of Service

Monday through Friday 0800 - 1700 EST

Data Set Credit

Credit should always be given to the data source and/or originator when the data is transferred or printed.

Native Data Set Environment

(GLOBEX) 906 CITIPIX Ortho-rectified Digital Image Mosaics were delivered by GlobeXplorer in a TIFF raster file format (with World file). Each original image is 2030 meters x 2030 meters with a 15 meter overlap, and image file size in .TIFF format is approximately 530 MB.

Logical Consistency Report

The CITIPIX Ortho-rectified Digital Images (ODIs)presented in ORTHO_HF covers all of Cumberland County and some of Androscoggin County. The aerial photography was flown in April 2001at a photoscale of 1:10,800. The orthoimages produced from the photography have a pixel resolution (or ground sample distance) of 1/2 foot. CITIPIX ortho-rectification used high accuracy digital terrain models, geometric correction, and a mosaic process to create 2030 meter x 2030 meter georeferenced tiles that overlap the UTM NAD83 grid by ~15 meters in all directions. In ORTHO_HF these tiles are presented as a single mosaic.

Completeness Report

The CITIPIX ODIs in ORTHO_HF were acquired as part of a larger effort by the Maine Library of Geographic Information (established April 9, 2002 by L.D.2116) to obtain and/or create new high resolution digital orthophotography for Maine. CITPIX ODI were flown in 2001 and cover all of Cumberland County and some of Androscoggin County.

Horizontal Positional Accuracy Report

The accuracy and quality of the CITIPIX ODIs in ORTHOS_HF meet National Map Accuracy Standards 1:1,200 scale, plus/minus 1 meter or 3.33 feet, and is accurate for mapping applications at 1" = 100'.

Horizontal Positional Accuracy Value

Horizontal Positional Accuracy Explanation

Digital file features include high quality ground-level georeferencing, derived from accurate positioning and geometric corrections, and provide a digital photographic map suitable for applications requiring a 1:1200 National Map Accuracy Standard (NMAS).

Citation Information

Originator	GlobeXplorer
Publication Date	20030303
Title	(CITIPIX)CitiPix
Geospatial Data Presentation Form	remote-sensing image
Publication Place	Walnut Creek CA
Publisher	GlobeXplorer
Other Citation Details	High resolution, 6-inch and 1-foot ground resolution, 24-bit color imagery, precision geo-referenced and ortho-rectified aerial photography, accurate for 1"=100' mapping applications
Online Linkage	http://www.globexplore.org/citipix.html

Time of Day

unknown

Source Citation Abbreviation

citipix

Source Contribution

ORTHO_HF contains high resolution 24-bit color CITIPIX Ortho-rectified Digital Images (ODIs). Flown in April 2001, from Portland to Auburn ME.

Process Description

The ArcSDE in Oracle version of ORTHO_HF is a seamless mosaic of CITIPIX (GlobeXplorer trademark) Ortho-rectified Digital Images (ODIs). CITIPIX ODIs are derived from color photographs, taken from an altitude of approximately 10,800 feet (3,300 meters) above mean terrain, using a 12 inch (305-mm) focal length Zeiss TOP30 aerial camera. The aircraft is equipped with a high accuracy dual frequency GPS2 receiver operating in kinematic relative mode and camera orientation is measured by inertial3 sensor technology. The 12-inch (305 mm) focal length lens, when compared to the usual six-inch, minimizes the perspective distortion in high buildings down town contexts. The nominal scale of the photography is approximately 1:10,800. Since ODIs are mosaics and considering flight overlaps, only the central portion of each aerial photograph is used in the final assembly, representing approximately 28% of each photo's coverage.Zeiss-Intergraph PhotoScan TD high-resolution photogrammetric scanners are used to scan 10-inch wide color negative film rolls in a controlled environment room (temperature, humidity and dust). Scanner aperture (pixel size) is 1,814 dots per inch or 14 *m4 which, when used on a 1:10800 photo-scale image, yields a ground pixel size of approximately 6 inches (15 cm), and which produces a color image of 16,700 by 16,700 24-bit pixels. This level of scanning resolution closely matches the film grain, which is between 10 and 12 *m, thus very close to 100% of the information present on the film itself is recorded in the digital file. Accuracy of these scanners is better than 2 *m, and lens distortion falls within the same order of magnitude. This insures that each measured pixel is right where it should be.Ortho-rectification was performed by Kodak Global Imaging, a former Eastman Kodak Company no longer in operation, using it's own technology involving high accuracy digital terrain models (DTMS) (created from CITIPIX stereo-models), geometric corrections and mosaicking processes. Each of these operations was performed by highly trained personnel, operating a tailor-made computerized processing chain.Once assembled in a continuous image covering sometimes thousands of photographs, base image data is separated in 2 km x 2km tiles, cut along Universal Transverse Mercator (UTM) even-numbered coordinate grid lines. A typical tile overlaps the UTM grid by an added 15 meters in all directions, the result being 2030 meters x 2030 meters tiles, overlapping each other by 30 meters: this is the default format of all ODI tiles produced and archived... Georeference for each tile is computed from accurate ortho-rectification and mosaicking processes. Each tile is given a pixel/ground transformation matrix (with zero-rotation), included in the file georeferencing parameters. UTM or State Plane Coordinate System (SPCS7), North American Datum (NAD83) or NAD27, X and Y coordinates are computed for each tile...Due to the high level of accuracy in the ortho-rectification and georeferencing processes, seam lines are often hardly visible to untrained eyes, thanks to operator-controlled, computer assisted seam line positioning on the final mosaic.

Process Date

2001

Contact Organization

(GLOBEX) GlobeXplorer

Address Type

physical address

Address

3021 Citrus Circle Suite 150

City

Walnut Creek

State or Province

Postal Code

94598

Contact Voice Telephone

800 417 7808 or 925 280 8765

Contact Facsimile Telephone

925 280 8760

Contact Electronic Mail Address

info@globexplorer.com or http://www.globexplorer.com

Process Description

The MrSid versions of the ORTHO_HF images were cropped and compressed using LizardTech's GeoExpress Command Line 3.1 software (www.lizardtech.com). The original 2km x 2km .tif images from Globexplorer were provided to MEGIS as multi-band TIFF images with no compression. The images were cropped to 1km x 1km tiles using 1000-meter UTM boundaries, plus a 2-pixel (.3m) buffer. Images were compressed at a ration of 12:1 using 5 zoom levels and were stored as MrSID Generation 2 files. The compression and cropping were all done in a single operation using command-line tools in the software. The images were done in batches of roughly 100GB and processed using an ArcInfo Arc Macro Language (AML) script which determined the UTM coordinates and passed the appropriate arguments to the GeoExpress software.

Process Date

2003

Contact Organization

(MEDEP) Maine Department of Environmental Protection

Contact Position

Senior Database Analyst

Address Type

mailing address

Address

SHS 17

City

Augusta

State or Province

Postal Code

04333

Country

USA

Contact Voice Telephone

(207)287-4292

Contact Facsimile Telephone

(207)287-7896

Indirect Spatial Reference

906 images all of Cumberland County

Direct Spatial Reference Method

Raster

Raster Object Type

Pixel

Row Count

506868

Column Count

546867

Grid Coordinate System Name

Universal Transverse Mercator

UTM Zone Number

Scale Factor at Central Meridian

0.9996

Longitude of Central Meridian

-69

Latitude of Projection Origin

False Easting

500000

False Northing

Planar Coordinate Encoding Method

Abscissa Resolution

Ordinate Resolution

Horizontal Datum Name

North American Datum of 1983

Ellipsoid Name

Geodetic Reference System 80

Semi-major Axis

6378137

Denominator of Flattening Ratio

298.257

Contact Organization

Maine Office of Geographic Information Systems

Contact Position

GIS Coordinator

Address Type

mailing address

Address

State House Station 174

City

Augusta

State or Province

Postal Code

04333-0174

Country

USA

Contact Voice Telephone

(207) 624-7700

Contact Facsimile Telephone

(207) 287-3842

Hours of Service

Monday through Friday 0800 - 1700 EST

Distribution Liability

Users must assume responsibility to determine the usability of this data for their purposes.

Format Name

WMS

Format Version Number

1.1

Format Specification

OpenGIS (OGC) Web Map Service (WMS)

Format Information Content

MEGIS has created a web based application for Maine GIS data that adheres to the OpenGIS Consortium (OGC) Web Mapping Specification (WMS 1.1.1) which allows map servers to create and send standard map images over the Web.

Network Resource Name

http://www.maine.gov/geolib/wms.htm

Fees

None

Ordering Instructions

A WMS is not a web application which you can see in a web browser; rather, it requires you to add the service to a GIS software application.

Metadata Reference Information

Metadata Date

20030711

Metadata Review Date

20100119

Metadata Contact

Contact Organization	(MEGIS) Maine Office of Geographic Information Systems
Contact Person	GIS Coordinator
Contact Position	GIS Coordinator
Address Type	mailing address
Address	State House Station 174
City	Augusta
State or Province	ME
Postal Code	04333-0174
Country	USA
Contact Voice Telephone	207 624-7700
Contact Facsimile Telephone	207 287-3842
Hours of Service	Monday through Friday 0800 - 1700 EST

Metadata Access Constraints

none

Metadata Use Constraints

none