Allentown_USGS_Orthoimagery

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator:NV5 Geospatial

Publication_Date:20250130

Title:

Allentown_USGS_Orthoimagery

Geospatial_Data_Presentation_Form:remote-sensing image

Description:

Abstract:

       Product: This orthoimagery data set includes 0.25 digital nadir orthoimages in 8-bit 4-band (RGB-IR) GeoTIFF tiles and 3-band (RGB) oblique images.
       Geographic Extent: 1 county in Pennsylvania, covering approximately 28 total square miles.
       Dataset Description: The Allentown_USGS_Orthoimagery project called for the planning, acquisition, processing, and derivative products of oblique and nadir imagery data to be collected at a ground sample distance (GSD) of 0.25. Project specifications are based on the American Society of Photogrammetry and Remote Sensing (ASPRS) standards. The data were developed based on a horizontal projection/datum of NAD 1983 2011 StatePlane Pennsylvania South FIPS 3702 Ft US, Foot US. Imagery data were delivered as 0.25 ft 8-bit 4-band (RGB-IR) GeoTIFF tiles 0.25 ft 3-band (RGB) oblique images. Tiled deliverables contained 129 individual 2500 ft x 2500 ft tiles.
       Ground Conditions: Imagery was collected in spring 2024, while no snow was on the ground and rivers were at or below normal levels. NV5 Geospatial completed a field survey of 26 ground control (calibration) points along with 30 blind QA points (total of 56 points) as an independent test of the accuracy of this project.  The imagery data was post processed to meet task order specifications and was produced to meet ASPRS horizontal accuracy guidelines.

Purpose:

These data depict geographic features on the surface of the earth. The dataset was created to update imagery data for Pennsylvania.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date:20240324

Ending_Date:20240324

Currentness_Reference:

Ground condition

Status:

Progress:Complete

Maintenance_and_Update_Frequency:None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate:-75.5583413201

East_Bounding_Coordinate:-75.4111200121

North_Bounding_Coordinate:40.6439142163

South_Bounding_Coordinate:40.5450578387

Keywords:

Theme:

Theme_Keyword_Thesaurus:None

Theme_Keyword:0.25 orthoimage

Theme_Keyword:GeoTIFF

Theme_Keyword:rectified photograph

Theme_Keyword:rectified image

Theme_Keyword:orthophoto

Theme_Keyword:natural color orthophoto

Theme_Keyword:orthoimage

Theme_Keyword:image map

Place:

Place_Keyword_Thesaurus:None

Place_Keyword:Pennsylvania

Place_Keyword:Lehigh County

Access_Constraints:No restrictions apply to these data.

Use_Constraints:

None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of their limitations. Acknowledgement of the organization providing these data to the public would be appreciated for products derived from these data.

Data_Set_Credit:

NV5 Geospatial

Native_Data_Set_Environment:

Windows 10.1; Esri ArcGIS Pro; ImageStation Suite 2022; Leica MissionPro; Inpho 13

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Radiometry is verified by visual inspection of the digital orthophoto. Slight systematic radiometric differences may exist between adjacent orthoimage files; these are due primarily to differences in source image capture dates and sun angles along flight lines. These differences can be observed in an image's general lightness or darkness when it is compared to adjacent orthoimage file coverages. Tonal balancing may be performed over a group of images during the mosaicking process which may serve to lighten or darken adjacent images for better color tone matching.

Logical_Consistency_Report:

All GeoTIFF tagged data and image file sizes are validated using commercial GIS software to ensure proper loading before being archived. This validation procedure ensures correct physical format and field values for tagged elements. Seamlines and tile edges are visually inspected. Seamline mismatches are corrected unless the overall displacement is less than 2 pixel(s).

Completeness_Report:

Orthoimages are visually inspected for completeness to ensure that no gaps or image misplacements exist within and between adjacent images. These images are derived by mosaicking multiple images to ensure complete coverage. Source imagery is cloud free.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The project specifications require that only horizontal accuracy be computed for orthoimagery files. The required accuracy was meet or exceed ASPRS standards. The horizontal accuracy was tested with 30 checkpoints located throughout the project area. These checkpoints were not used in the calibration or post-processing of the imagery data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies. The x and y positions of where the checkpoints fell on the orthoimagery were collected. These values were then compared to the surveyed control point x and y values.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value:0.0131

Horizontal_Positional_Accuracy_Explanation:

Tested 0.0131 meters (0.04 feet) RMSEx. The RMSEx of the imagery was calculated using 30 independent checkpoints.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value:0.0118

Horizontal_Positional_Accuracy_Explanation:

Tested 0.0118 meters (0.04 feet) RMSEy. The RMSEy of the imagery was calculated using 30 independent checkpoints.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value:0.0176

Horizontal_Positional_Accuracy_Explanation:

Tested 0.0176 meters (0.06 feet) RMSEr. The RMSEr of the imagery was calculated using 30 independent checkpoints.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

There is no vertical component for orthophotos.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator:NV5

Publication_Date:20250130

Title:

GPS Photo Control Survey

Geospatial_Data_Presentation_Form:vector digital data and tabular data

Type_of_Source_Media:online

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date:20240805

Source_Currentness_Reference:

ground condition

Source_Citation_Abbreviation:

CONTROL

Source_Contribution:

NV5 Geospatial performed a geodetic control survey in support of the digital orthophoto production project. A total of 26 points were used for aerotriangulation. A total of 30 points were used for QC testing. Please see the survey report for more information.

Source_Information:

Source_Citation:

Citation_Information:

Originator:NV5 Geospatial

Publication_Date:20250130

Title:

Georeferenced Single Frames

Geospatial_Data_Presentation_Form:remote-sensing image

Type_of_Source_Media:external hard drive

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date:20240324

Ending_Date:20240324

Source_Currentness_Reference:

ground condition

Source_Citation_Abbreviation:

PHOTO

Source_Contribution:

Aerial imagery was acquired using a UltraCam Osprey camera with a flight design that included a total of 39 flight lines. Aerial imagery was supplemented with the simultaneous acquisition of airborne GPS/IMU data, which captured the ground coordinate for the nadir point of each photograph. Aerial imagery was exposed at an altitude of 5600 feet above mean terrain.

Source_Information:

Source_Citation:

Citation_Information:

Originator:NV5 Geospatial

Publication_Date:20250130

Title:

Aerotriangulation

Geospatial_Data_Presentation_Form:model

Type_of_Source_Media:online

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date:20240606

Source_Currentness_Reference:

ground condition

Source_Citation_Abbreviation:

AT

Source_Contribution:

Softcopy aerotriangulation was performed utilizing the airborne GPS/IMU data, 26 GPS ground control points and image coordinate measurements allowing the direct computation of the exterior orientation parameters for each image of the project.

Source_Information:

Source_Citation:

Citation_Information:

Originator:NV5 Geospatial

Publication_Date:20250130

Title:

DEM

Geospatial_Data_Presentation_Form:raster digital data

Type_of_Source_Media:online

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date:2024

Source_Currentness_Reference:

publication date

Source_Citation_Abbreviation:

DEM

Source_Contribution:

A compilation of topographic land form elevation datasets developed using in-house LiDAR data and data from the National Elevation Dataset for use in developing digital ortho imagery.

Process_Step:

Process_Description:

Imagery Acquisition: Digital aerial imagery was obtained using a UltraCam Osprey camera equipped with Airborne GPS/IMU. A total of 39 flight lines were collected in the spring 2024 in multi-spectral (RGB-IR) format. The 0.25 imagery was acquired at an altitude above mean terrain of 5600 feet to yield a pixel resolution suitable for photogrammetric mapping and orthophoto production. The imagery was collected under conditions free from clouds and cloud shadows, smoke, fog, haze, light streaks, snow, ice on water bodies, flooding, excessive soil moisture, and foliage. The imagery consisted of blue, green, red, and infrared bands. Imagery for the photogrammetric mapping and digital orthophotos was captured according to task order specifications regarding, snow, haze, and cloud cover.

Source_Used_Citation_Abbreviation:

RAWs

Process_Date:20250130

Source_Produced_Citation_Abbreviation:

Georefs

Process_Step:

Process_Description:

Ground Control Point Collection: A total of 26 control points were established throughout the project area using a combination of conventional and GPS survey methods in order to support softcopy aerotriangulation and photogrammetric mapping meeting the accuracies specified in this Scope of Work. Ground control collection followed requirements set forth in the task order specifications. NV5 Geospatial completed a field survey of 26 ground control (calibration) points along with 30 blind QA points (total of 56 points) as an independent test of the accuracy of this project. Please see the survey report for more information.

Source_Used_Citation_Abbreviation:

Geodetic control

Process_Date:20250130

Source_Produced_Citation_Abbreviation:

Control

Process_Step:

Process_Description:

Aerotriangulation: Softcopy aerotriangulation was performed on one large block of imagery. The airborne GPS/IMU data, GPS ground control, and image coordinate measurements were utilized to allow the direct computation of the exterior orientation parameters for each image frame to support the photogrammetric process and orthophoto production.

Source_Used_Citation_Abbreviation:

ABGPS

Source_Used_Citation_Abbreviation:

Control

Source_Used_Citation_Abbreviation:

RAWs

Process_Date:20250130

Source_Produced_Citation_Abbreviation:

AT

Process_Step:

Process_Description:

Surface Creation: This process involved the development of seamless topographic landform elevation dataset utilizing in-house LiDAR data and data from the National Elevation Dataset to support the production of digital orthophotography that meet or exceed required orthophoto horizontal accuracy. The topographic features included a grid of elevation points and may include break lines that define ridges, valleys, edge of water, transportation features and abrupt changes in elevation. The final DEM is suitable for orthophoto production only (not suitable for contour generation). The DEM is used to then generate a Triangulated Irregular Network (TIN) to support orthophoto production. The final DEM used for orthophoto production was delivered in countywide rasters in a file geodatabase.

Source_Used_Citation_Abbreviation:

DEM

Source_Used_Citation_Abbreviation:

LiDAR

Process_Date:20250130

Source_Produced_Citation_Abbreviation:

DEM

Process_Step:

Process_Description:

Orthophoto Processing: Utilizing all four bands [blue (B), green (G), red (R), and infrared (IR)] digital orthorectification was performed using bilinear interpolation algorithms resulting in a spatial and radiometric transformation of the digital image from line/sample space into NAD 1983 2011 StatePlane Pennsylvania South FIPS 3702 Ft US, Foot US. The interior and exterior orientation parameters from the aerotriangulation process were used to project each pixel into the ground coordinate system, while the ortho grade DEM was used to correct for relief displacement. Radiometric correction software and techniques were used to create orthophoto files that minimize the appearance of image seams and without loss of feature signature. The final Nadir radiometry is applied to the Oblique imagery in order to ensure consistent radiometry project wide. Orthophotos are checked for geometric accuracy, image quality, and are tonally balanced to produce a uniform contrast and tone across the entire project. The individual overlapping orthophoto frames were mosaicked together. The ortho photos were meet ASPRS horizontal accuracy standards.

Source_Used_Citation_Abbreviation:

Georefs

Source_Used_Citation_Abbreviation:

AT

Source_Used_Citation_Abbreviation:

Control

Source_Used_Citation_Abbreviation:

DEM

Process_Date:20250130

Source_Produced_Citation_Abbreviation:

Orthos

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method:Raster

Raster_Object_Information:

Raster_Object_Type:pixel

Row_Count:10000

Column_Count:10000

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name:State Plane Coordinate System 1983

State_Plane_Coordinate_System:

SPCS_Zone_Identifier:3702

Lambert_Conformal_Conic:

Standard_Parallel:39.9333333333

Standard_Parallel:40.9666666667

Longitude_of_Central_Meridian:-77

Latitude_of_Projection_Origin:39.3333333333

False_Easting:1968500

False_Northing:0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method:row and column

Coordinate_Representation:

Abscissa_Resolution:0.25

Ordinate_Resolution:0.25

Planar_Distance_Units:Foot US

Geodetic_Model:

Horizontal_Datum_Name:D NAD 1983 2011

Ellipsoid_Name:Geodetic Reference System 80

Semi-major_Axis:6378137.0

Denominator_of_Flattening_Ratio:298.257222101

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

Three band orthoimagery is organized in three color bands or channels which represent the red, green, and blue (RGB) portions of the spectrum. Four band orthoimagery is organized in four color bands or channels which represent the red, green, blue (RGB), and near infrared (IR) portions of the spectrum. Each image pixel is assigned a triplet or quadruplet of numeric values, one for each color band. Numeric values range from 0 to 255.

Entity_and_Attribute_Detail_Citation:

U.S. Department of the Interior, U.S. Geological Survey, 1996, Standards for Digital Orthophotos: Reston, VA.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Organization:Pennsylvania Spatial Data Access (PASDA)

Contact_Address:

Address_Type:mailing and physical address

Address:

115 Land and Water building

City:University Park

State_or_Province:Pennsylvania

Postal_Code:16802

Country:United States

Contact_Voice_Telephone:(814) 865 - 8792

Contact_Electronic_Mail_Address:pasda@psu.edu

Distribution_Liability:

The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.

Metadata_Reference_Information:

Metadata_Date:20250130

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:NV5 Geospatial

Contact_Address:

Address_Type:mailing and physical

Address:

523 Wellington Way

City:Lexington

State_or_Province:KY

Postal_Code:40503

Country:USA

Contact_Voice_Telephone:859-277-8700

Contact_Facsimile_Telephone:859-277-8901

Hours_of_Service:Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)

Metadata_Standard_Name:FGDC Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version:FGDC-STD-001-1998

Metadata_Access_Constraints:None.

Metadata_Use_Constraints:

None.

Metadata_Security_Information:

Metadata_Security_Classification_System:None.

Metadata_Security_Classification:Unclassified

Metadata_Security_Handling_Description:

NONE

Metadata_Extensions:

Online_Linkage: None.

Profile_Name:None.