Metadata: National Agricultural Imagery Program (NAIP), Minnesota, 2021, Digital Orthorectified Images (DOQ)

National Agricultural Imagery Program (NAIP), Minnesota, 2021, Digital Orthorectified Images (DOQ)

This page last updated: 04/04/2022
Metadata created using Minnesota Geographic Metadata Guidelines

Go to Section:
  1. Overview
  2. Data Quality
  3. Data Organization
  4. Coordinate System
  5. Attributes
  6. Distribution - Get Data
  7. Metadata Reference

Section 1: Overview

Originator:U.S. Department of Agriculture (USDA), Farm Service Agency (FSA), Aerial Photography Field Office (APFO)

Title: National Agricultural Imagery Program (NAIP), Minnesota, 2021, Digital Orthorectified Images (DOQ)

Abstract: This data set contains 4-band natural color and false color infrared (CIR) imagery from the National Agricultural Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S. A primary goal of the NAIP program is to enable availability of ortho imagery within one year of acquisition.

The source files are 60-centimeter (approx. 2-foot) ground sample distance (GSD) ortho imagery rectified to within +/- 4 meters to reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP) or from the National Agriculture Imagery Program (NAIP). The tiling format of NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle with a 300 pixel buffer on all four sides. NAIP imagery is formatted to the UTM coordinate system using the North American Datum of 1983 (NAD83). NAIP imagery may contain as much as 10% cloud cover per tile.

The county mosaic files downloadable from the USDA NRCS Geospatial Data Gateway (natural color and color infrared) were generated by compressing NAIP imagery that covers the county extent. MrSID compression was used. Target values for the compression ratio are 15:1.

Only the natural color imagery is currently available via a WMS service.

The Minnesota Geospatial Information Office (MnGeo) created this metadata record to describe the entire NAIP 2021 dataset, using information from FSA metadata. Each county file available from the USDA NRCS Geospatial Data Gateway is accompanied by the original FSA metadata for that county.

Purpose: NAIP imagery is typically 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 1 meter and 1/2 meter 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 who use the imagery for a variety of purposes including land use planning and natural resource assessment. NAIP is also used for disaster response often providing the most current pre-event imagery.

Time Period of Content Date: 2021

Currentness Reference: Summer and Fall 2021. See the IDATE attribute in the seamline shapefile for the state or accompanying each county download to find out the date(s) that the source imagery was acquired.

Options to access the dates:
1. A seamline shapefile for Minnesota may be downloaded from NRCS:
3. The shapefiles are included with the MrSID county mosaics downloadable from NRCS

Progress: Complete

Maintenance and Update Frequency: Irregular

Spatial Extent of Data: Minnesota

Bounding Coordinates: -97.5

Place Keywords: Minnesota, MN

Theme Keywords: imageryBaseMapsEarthCover, Digital Orthorectified Image, Digital Orthophoto Quad, Ortho, Orthophoto, DOQ, NAIP, Compliance, Air Photo, Air Photography, Aerial Photo, Aerial Photography

Theme Keyword Thesaurus: ISO 19115 Topic Category

Access Constraints: None

Use Constraints: The USDA-FSA Aerial Photography Field Office asks to be credited in derived products.

If defects are found in the NAIP imagery during the 1 year warranty period such as horizontal offsets, replacement imagery may be provided. Imagery containing defects that require the acquisition of new imagery, such as excessive cloud cover, specular reflectance, etc., will not be replaced within a NAIP project year.

Contact Person Information: Supervisor Customer Services Section,
USDA-FSA Aerial Photography Field Office
2222 West 2300 South
Salt Lake City, UT  84119
Phone: 801-844-2922

Browse Graphic: Click to view a data sample.
Graphic showing the entire state

Associated Data Sets: For information on other air photos available for Minnesota, including other years of NAIP imagery, see

Section 2: Data Quality

Attribute Accuracy: NAIP imagery may contain as much as 10% cloud cover per tile.

Imagery can show marked color differences between areas flown at different dates. For example, an area flown during the growing season in August will appear very green; it could be adjacent to an area flown in October after harvest which appears mostly brown. See the preview graphic:

Logical Consistency: N/A

Completeness: No report

Horizontal Positional Accuracy: NAIP Specifications. The quarter-quad files are 0.6 meter ground sample distance (GSD) ortho imagery rectified within +/- 4 meters to reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP) or from the National Agriculture Imagery Program (NAIP).

Vertical Positional Accuracy: N/A

Lineage: Flight planning was performed in Leica MissionPro 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 16,000 feet above ground level for acquisition with sidelap of 27% was used for flight planning parameters.

Five Cessna Conquests and a Cessna 414 were utilized for acquisition, the seamline shapefile clarifies which aircraft were used for a given area. All aircraft were equipped with Leica ADS100 systems for data capture. The Leica ADS100 pushbroom 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. These data are used in the Post Processing Software to eliminate the radiometric and geometric distortion.

All aerial imagery was collected with associated GPS/IMU data. ADS 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. After post processing was complete, all imagery was triangulated using Leica XPro 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. If the block does not fit the control points within specifications the pass and tie points were reviewed for blunders and weak areas. If, after these corrections were made, the block still does not fit the control well the GPS and IMU processing were reviewed.

Once the block has proper statistics and fits the control to specifications, the final bundle adjustment was made. As AT points are frequently on man-made and other vertical features not included in the DEM, these orthopoints can only be used to indicate regions of error by the clusters of points that predict excessive horizontal displacement. 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 imagery. 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 seamline areas where 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, calibrated monitors and various brands of monitor calibration colorimeters. Leica XPro was used for post processing of ADS pushbroom data, triangulation and orthorectification. SURDEX software was used to 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 Inertial Explorer software from Novatel. Aerial Triangulation and orthorectification was performed using Leica XPro. SURDEX software was used to adjust for minor radiometric variation between adjacent images. 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.

Section 3: Spatial Data Organization (not used in this metadata)

Section 4: Coordinate System

Horizontal Coordinate Scheme: Universal Transverse Mercator

UTM Zone Number: 15

Horizontal Datum: NAD83

Horizontal Units: meters

Vertical Datum: not applicable

Vertical Units:

Depth Datum: not applicable

Depth Units:

Cell Width: 0.6

Cell Height: 0.6

Section 5: Attributes

Overview: Natural color imagery has 8-bit pixels per band, 3 band RGB represent brightness values 0 - 255.

Detailed Citation: None

Table Detail:

Section 6: Distribution

Publisher: U.S. Department of Agriculture (USDA), Farm Service Agency (FSA), Aerial Photography Field Office (APFO)

Publication Date: 05/2020

Contact Person Information: Nancy Rader, GIS Data Specialist
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street, Room 300
St. Paul, MN  55155
Phone: 651-201-2489

Distributor's Data Set Identifier: NAIP 2021

Distribution Liability: 1. FSA Liability Statement: In no event shall the creators, custodians, or distributors of this information be liable for any damages arising out of its use (or the inability to use it).

2. MnGeo's disclaimer:

Ordering Instructions: The imagery is available free online by clicking below after Online Linkage.

1. View the natural color files seamlessly via a WMS service without having to download the files.

2. Download each county file in MrSID format (natural color or color infrared) and accompanying seamline shapefile from the U.S. Dept. of Agriculture, Natural Resources Conservation Service's Geospatial Data Gateway site:

Online Linkage: I AGREE to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process, link to a service, or provide more instructions. See "Ordering Instructions" above for details.

Section 7: Metadata Reference

Metadata Date: 04/04/2022

Contact Person Information: Nancy Rader, GIS Data Specialist
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street, Room 300
St. Paul, MN  55155
Phone: 651-201-2489

Metadata Standard Name: Minnesota Geographic Metadata Guidelines

Metadata Standard Version: 1.2

This page last updated: 04/04/2022
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