Metadata for Montana 2015 NAIP Orthophotos, 24-Kilometer Tiles Metadata for Montana 2015 NAIP Orthophotos, 24-Kilometer Tiles

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Identification Information:

Citation:

Originator:

U.S. Dept of Agriculture
Farm Services Agency
Aerial Photography Field Office

Publication date: 06/29/2017

Title: Montana 2015 NAIP Orthophotos, 24-Kilometer Tiles

Publication place: Helena, Montana
Publisher: Montana State Library

Online linkage: http://geoinfo.msl.mt.gov/Data/Aerial_Photos/NAIP_2015

Larger Work Citation:

Title: Montana 2015 NAIP Orthophotos
Online linkage: http://mslapps.mt.gov/Geographic_Information/Data/DataList/datalist_Details.aspx?did={b5a64e60-eac0-81e3-9be7-525861b86ab6}

Abstract:

This data set contains imagery from the National Agriculture Imagery Program (NAIP). These data are digital aerial photos of most the state of Montana, taken in 2015 and 2016. Due to cloud cover, wildfire smoke, and snow cover the imagery acquisition was not completed in 2015. Additional photos were taken in 2016. A map showing the imagery that was collected is available at http://docs.msl.mt.gov/geoinfo/Images/Metadata/NAIP_2015.jpg

This version of the data consists of a downloadable collection of 654 24x24 kilometer orthorectified 4-band images in MrSID format. The pixel resolution of the collection is 1 meter and the images are in Montana State Plane NAD83 coordinates, units meters. The FTP folder containing these images is https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2015_NAIP/24_km_tiles.

The data were derived from a collection 10,888 4-band (near infrared, red, green and blue) TIFF images, each of about 170 megabytes. The original TIFF images, in UTM coordinates, are available on request.

The data are also downloadable as a collection of compressed county mosaic (CCM) natural color MrSID images. These data are in UTM coordinates. The FTP folder containing these images is https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2015_NAIP/UTM_County_Mosaics.

An ESRI shapefile index showing the extent of the individual MrSID image files is available at https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2015_NAIP/NAIP_2015_tile_index.zip.

An ESRI shapefile index showing the dates and times the images were acquired is available at https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/Imagery/2015_NAIP/NAIP_2015_Dates.zip.

Time period of content:

Beginning date: 06/15/2015
Ending date: 08/25/2016
Currentness reference: ground condition

Access constraints: None

Use constraints:

The Montana State Library provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time.

Point of contact:

Aerial Photography Field Office (APFO)
222 West 2300 South
Salt Lake City, Utah 84119-2020
Telephone: 801-844-2922
Fax: 801-956-3653
E-Mail: apfo.sales@slc.usda.gov

Data Quality Information:

Horizontal Positional Accuracy Report:

NAIP horizontal accuracy specifications require a match of plus or minus 6 meters between objects on the ground and their position in the imagery.

Lineage:

Source information:

Originator:: U.S. Dept of Agriculture
Farm Services Agency
Aerial Photography Field Office
Publication date: 2016
Title: Aerial Photography
Beginning date: 06/15/2015
Ending date: 08/25/2016

Process step:

Digital imagery was collected at a nominal GSD of 40cm using eight Cessna 441 aircraft and two Beechcraft King Air flying at an average flight height of 5000m above ground level. All aircraft flew with Leica Geosystem's ADS100/SH100 digital sensors with firmware 4.42. Each sensor collected 12 image bands Red, Green, Blue and Near-infrared at each of three look angles; Backward 19 degrees, Forward 26 degrees and Nadir. The Nadir Green band was collected in high resolution mode effectively doubling the resolution for that band. The ADS100 spectral ranges are; Red 619-651nm, Green 525-585nm, Blue 435-495nm and Near-infrared at 808-882nm.

The CCD arrays have a pixel size of 5.0 microns in a 20000x1 format at nadir; a 18000x1 format at the backward look angle and a 16000x1 format at the forward look angle. The CCD's have a dynamic range of 72db and the A/D converters have a resolution of 14bits. The ADS is a push-broom sensor and the ground footprint of the imagery at a nominal GSD of 40cm is approximately 8km wide by the length flightline. The maximum flightline length is limited to approximately 240km.

The factory calibrations and IMU alignments for each sensor (Serial Numbers: 10511,10512,10514,10519, 10527,10528,10531,10534,10540,10554) were tested and verified by in-situ test flights before the start of the project. The Leica MissionPro Flight Planning Software is used to develop the flight acquisition plans. Flight acquisition sub blocks are designed first to define the GNSS base station logistics, and to break the project up into manageable acquisition units. The flight acquisition sub blocks are designed based on the specified acquisition season, native UTM zone of the DOQQs, flight line length limitations (to ensure sufficient performance of the IMU solution) as well as air traffic restrictions in the area. Once the sub blocks have been delineated they are brought into MissionPro for flight line design. The design parameters used in MissionPro will be 27 to 35% lateral overlap and 40cm resolution. The flight lines have been designed with a north/south orientation. The design takes into account the latitude of the state, which affects line spacing due to convergence as well as the terrain. SRTM elevation data is used in the MissionPro design to ensure the 50cm GSD is achieved over all types of terrain.

The raw data was downloaded from the sensors after each flight using Leica XPro software. The imagery was then georeferenced using the 200Hz GPS/INS data creating an exterior orientation for each scan line (x/y/z/o/p/k). Leica Xpro APM software was used to automatically generate tiepoint measurements between the foward 26 degree, nadir and backward 19 degree look angles for each line and to tie all flight lines together. The resulting point data and exterior orientation data were used to perform a full bundle adjustment using ORIMA software. Blunders were removed, and additional tie points measured in weak areas to ensure a robust solution.

Once the point data was clean and point coverage was acceptable, photo-identifiable GPS-surveyed ground control points were introduced into the block adjustment. The bundle adjustment process produces revised exterior orientation data for the sensor with GPS/INS, datum, and sensor calibration errors modeled and removed. Using the revised exterior orientation from the bundle adjustment, orthorectified image strips were created with Xpro software and the June 2015 USGS 10m NED DEM. The Xpro orthorectification software applies an atmospheric-BRDF radiometric correction to the imagery. This correction compensates for atmospheric absorption, solar illumination angle and bi-directional reflectance. The orthorectified strips were then overlaid with each other and the ground control to check accuracy.

Once the accuracy of the orthorectified image strips were validated the strips were then imported into Inpho's OrthoVista 6.0.1 package which was used for the final radiometric balance, mosaic, and DOQQ sheet creation. The final DOQQ images were produced with a 300m buffer and a ground pixel resolution of 1 meter.

Process step:

A 24x24-kilometer tile system was set up for Montana and a Python macro was written for the ESRI arcpy module that compared the extent of each tile with the extent of the TIFF images. This macro produces an XML file formatted to be loaded as a project by GeoExpress, a software package produced by Lizard Tech (http://www.lizardtech.com) that manipulates image data and produces MrSID images. The GeoExpress project compresses data from the appropriate TIFF images that cover each tile clips the data to the extent of the tile.


Process date: 03/06/2016

Spatial Reference Information:

Horizontal coordinate system definition:

Grid coordinate system name: State Plane Coordinate System

SPCS zone identifier: 2500

Lambert conformal conic: