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Short Citation:
OCM Partners, 2024: 2021 Maine NAIP Digital Ortho Photo Imagery,

Item Identification

Title: 2021 Maine NAIP Digital Ortho Photo Imagery
Status: Completed
Publication Date: 2022-09-19

This data set contains imagery from the National Agriculture Imagery Program (NAIP). The NAIP program is administered by USDA FSA and has been established to support two main FSA strategic goals centered on agricultural production. These are, increase stewardship of America's natural resources while enhancing the environment, and to ensure commodities are procured and distributed effectively and efficiently to increase food security. The NAIP program supports these goals by acquiring and providing ortho imagery that has been collected during the agricultural growing season in the U.S. The NAIP ortho imagery is tailored to meet FSA requirements and is a fundamental tool used to support FSA farm and conservation programs. Ortho imagery provides an effective, intuitive means of communication about farm program administration between FSA and stakeholders. New technology and innovation is identified by fostering and maintaining a relationship with vendors and government partners, and by keeping pace with the broader geospatial community. As a result of these efforts the NAIP program provides three main products: DOQQ tiles, Compressed County Mosaics (CCM), and Seamline shape files. The Contract specifications for NAIP imagery have changed over time reflecting agency requirements and improving technologies. These changes include image resolution, horizontal accuracy, coverage area, and number of bands. In general, flying seasons are established by FSA and are targeted for peak crop growing conditions. The NAIP acquisition cycle is based on a minimum 3 year refresh of base ortho imagery. The tiling format of the NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle with a 300 pixel buffer on all four sides. NAIP quarter quads are formatted to the UTM coordinate system using the North American Datum of 1983. NAIP imagery may contain as much as 10% cloud cover per tile.


NAIP imagery is available for distribution within 60 days of the end of a flying season and is intended to provide current information of agricultural conditions in support of USDA farm programs. For USDA Farm Service Agency, the 30 or 60 centimeter GSD product provides an ortho image base for Common Land Unit boundaries and other data sets. The NAIP imagery is generally acquired in projects covering full states in cooperation with state government and other federal agencies that use the imagery for a variety of purposes including land use planning and natural resource assessment. The NAIP is also used for disaster response. While suitable for a variety of uses, prior to 2007 the 2 meter GSD NAIP imagery was primarily intended to assess "crop condition and compliance" to USDA farm program conditions. The 2 meter imagery was generally acquired only for agricultural areas within state projects.


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None Aerial Compliance
None Compliance
None Digital Ortho rectified Image
None farming
None Ortho Rectification
None Quarter Quadrangle

Temporal Keywords

Thesaurus Keyword
None 2021

Spatial Keywords

Thesaurus Keyword
Geographic Names Information System Maine
Geographic Names Information System ME

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: Irregular
Data Presentation Form: Image (digital)
Entity Attribute Overview:

32-bit pixels, 4 band color(RGBIR) values 0 - 255

Entity Attribute Detail Citation:


Distribution Liability:

Users must assume responsibility to determine the appropriate use of these data. DATA SHOULD NOT BE USED FOR LEGALLY BINDING APPLICATIONS.

Support Roles

Data Steward

CC ID: 1184524
Date Effective From: 2022-09-19
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 1184526
Date Effective From: 2022-09-19
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 1184527
Date Effective From: 2022-09-19
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 1184525
Date Effective From: 2022-09-19
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1318183
W° Bound: -71.299
E° Bound: -66.799
N° Bound: 47.589
S° Bound: 42.833

Extent Group 1 / Time Frame 1

CC ID: 1318182
Time Frame Type: Range
Start: 2021-07-23
End: 2021-10-07

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Grid Representation 1

CC ID: 1184539
Dimension Count: 2
Cell Geometry: Point
Transformation Parameters Available?: No

Axis Dimension 1

Dimension Type: Row
Size: 1

Axis Dimension 2

Dimension Type: Column
Size: 1

Access Information

Security Class: Unclassified
Data Access Constraints:

There are no limitations for access.

Data Use Constraints:

None. The USDA-FSA Aerial Photography Field office

asks to be credited in derived products.

Distribution Information

Distribution 1

CC ID: 1184529
Download URL:
File Name: Customized Download

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

Distribution 2

CC ID: 1184530
Download URL:
File Name: Bulk Download

Simple download of data files.

Activity Log

Activity Log 1

CC ID: 1184533
Activity Date/Time: 2017-11-01

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 1184532
Activity Date/Time: 2017-11-14

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

Activity Log 3

CC ID: 1184534
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 1184535
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Technical Environment



Data Quality

Horizontal Positional Accuracy:

NAIP horizontal accuracy specifications have evolved over the life of the program. From 2003 to 2004 the specifications were as follows: 1-meter GSD imagery was to match within 3-meters, and 2-meter GSD to match within 10 meters of reference imagery. For 2005 the 1-meter GSD specification was changed to 5 meters matching the reference imagery. In 2006 a pilot project was performed using true ground specifications rather than reference imagery. All states used the same specifications as 2005 except Utah, which required a match of +/- 6 meters to true ground. In 2007 all specifications were the same as 2006 except Arizona used true ground specifications and all other states used reference imagery. In 2008 and subsequent years no 2-meter GSD imagery was acquired and all specifications were the same as 2007 except approximately half of the states acquired used true ground specifications and the other half used reference imagery. The 2008 states that used absolute ground control were; Indiana, Minnesota, New Hampshire, North Carolina, Texas, Vermont, and Virginia. Beginning in 2009, all NAIP imagery acquisitions used the +/- 6 meters to ground and in 2016 the specification was changed to +/- 4 meters to true ground.

Completeness Report:


Conceptual Consistency:

NAIP 3.75 minute tile file names are based

on the USGS quadrangle naming convention.


Process Steps

Process Step 1

CC ID: 1318176

DOQQ Production Process Description;

USDA FSA APFO NAIP Program 2021;

The imagery was collected using the following digital sensors:

Vexcel Condor M4.1 (Serial Number 435S52516X011066),

Vexcel Condor M4.1 (Serial Number 435S72614X210073),

Cameras are calibrated radiometrically and geometrically

by the manufacturer.

Collection was performed using a combination of the

following twin-engine aircraft with turbines flying

at 17,000 ft above mean terrain.

Plane types:

C441 Cessna Conquest

Tail numbers:



With this flying height, there is a 30% sidelap,

giving the collected data nominal ground sampling distance

of 15cm and rectified to 60cm.

Based-upon the CCD Array configuration present in

the Condor sensor, imagery for each flight

line is 48,460-pixels in width. Red, Green, Blue,

Near-Infrared and Panchromatic image bands were collected.

The Vexcel Condor has the following band specifications at 40% intensity:

Red 585-690,

Green 570-600,

Blue 425-530,

Near Infrared 700-830,

all values are in nanometers.

Flight planning was performed in IGI Plan over a

buffered boundary covering DOQQ extents provided by the USDA.

A 500m reduced resolution DEM file was used to determine

ground heights. A targeted flight altitude of approximately

17,000 feet above ground level for native 15 cm image

acquisition with sidelap of 30% was used

for flight planning parameters. Multiple aircraft were utilized

for acquisition, the seamline

shapefile clarifies which aircraft were used for a given area.

All aircraft were equipped with Vexcel

Condor systems where utilized for data

capture. The Vexcel Condor sensor

has been calibrated by the manufacturer as well as validated

against a local calibration range. The calibration includes

measuring the radiometric and geometric properties of the

camera. This data is used in the Post Processing Software

to eliminate the radiometric and geometric distortion.

All aerial imagery was collected with associated GPS/IMU

data. Condor collection requires high quality IMU data for

processing and was critical for early access hosting of digital

data to the web for USDA interim access and review.

Process Date/Time: 2022-01-10 00:00:00

Process Step 2

CC ID: 1318177

After early access web delivery was complete, all

imagery was triangulated using Vexcel Ultramap in which

the airborne GPS data was constrained to expected limits.

To validate the accuracy of the block adjustment derived from

GPS/IMU, sensor parameters and conjugate point measurements,

photo identifiable ground control points were field surveyed within

each State. These points were surveyed using GPS techniques to

produce coordinates that are accurate to +/- 0.25 meters RMSE in XYZ.

The GPS surveying techniques utilized assured that the coordinates

are derived in the required project datum and relative to an approved

National Reference System. Once the block has proper statistics and fits the

control to specifications, the final bundle adjustment was


The final adjustments assure a high quality relative adjustment

and a high quality absolute adjustment limited to the

airborne GPS data accuracy. This process assures the final

absolute accuracy of all geopositioned imagery. Both

signalized and photo identified ground control were used to

QC and control the IMU/GPS based aerial triangulation bundle

block solution. Surdex Grouping Tool provides real-time updates

of the USDA APFO Image Metrics. The image technician adjusts

image correction parameters to bring the radiometric

characteristics of large groups of images within the Image

Metrics ranges. For each project area the highest resolution

DEM or LiDAR was obtained and utilized for rectification of captured


Process Date/Time: 2022-01-10 00:00:00

Process Step 3

CC ID: 1318178

A visual inspection of the final DEM using color cycled

classification by elevation and a shaded relief was performed

to check for gaps, corruption and gross errors.

The predicted horizontal error for each

point was added as an attribute in the SURDEX enterprise

database. An operator reviews ortho seams

in areas these predicted errors indicate horizontal error in

excess of the contract specifications. Any imagery errors

introduced by source DEM required patching from an alternate

perspective or strip of photography.

Processing hardware used included various brands of survey grade

GPS receivers, various brands and models of computers,

RAID6 storage, calibrated monitors, various brands of monitor

calibration colorimeters. Vexcel Ultramap was used for post

processing of Condor data, and triangulation.

SURDEX software was used to orthorectify, color correct,

and remove bidirectional reflectance, vignetting and other

illumination trends. USDA APFO Image Metrics are measured and

images corrected to conform to the Image Metrics using

SURDEX software. GPS/IMU data was reduced to projected

coordinates in the appropriate UTM zone using

Applanix POSPac. SURDEX software was used

to calculate the optimal seam path, check seam topology and

create master tiles. SURDEX ortho software generates

occlusion/smear polygons used during seam review

of steep terrain. SURDEX software was used to

visually inspect master tiles for seam and image defects.

SURDEX software was used to project and cut final DOQQ image

files from masters. SURDEX software was used to create CCM

metadata. Lizardtech GeoExpress version was used

to create the CCM image file. SURDEX software was

used to perform final formatting, QC and naming of the DOQQ.

USGS metadata parser software was used to validate the metadata.

Various versions of Microsoft Windows were used in all phases of

production. Grouping Tool was used again after DOQQ and CCM

production to provide a quality assurance check. Individual

DOQQ and CCM may not meet the USDA APFO Image Metrics ranges

due to land cover. The goal is to have the state as a

whole meet the Image Metrics. All products are reviewed

by independent personnel prior to delivery.

The delivery is checked for omissions, commissions,

naming, formatting, specification compliance and data integrity.

Process Date/Time: 2022-01-10 00:00:00

Catalog Details

Catalog Item ID: 67912
GUID: gov.noaa.nmfs.inport:67912
Metadata Record Created By: Erik Hund
Metadata Record Created: 2022-09-19 18:11+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-11 12:43+0000
Metadata Record Published: 2024-01-11
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2019-12-26
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2020-12-26