Lubbock 2015 Digital Orthophotography

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Frequently anticipated questions:

What does this data set describe?

Title: Lubbock 2015 Digital Orthophotography
Abstract:
This digital orthophotography dataset consists of tiled orthophotos covering approximately 352 square miles as part the City of Lubbock 2015 digital orthophotography project. The 1,526 overlapped tiles of orthophotography depict four-band color (Red, Green, Blue, and Infrared (RGBI)) digital aerial photographs acquired in March 2015 during leaf-off conditions. The project tiling scheme of roughly one-quarter square mile tiles is organized according to the City's grid scheme. Lens and terrain distortion have been removed through orthorectification and tonal differences between adjacent images have been minimized to form a color-balanced mosaic of the entire project area. The project area includes all of the City jurisdiction and portions of Lubbock County in Texas. Orthorectified imagery corrects for geometric distortion and creates an image-based map with features represented appropriately at ground level. Above-ground features such as buildings and bridges may show some distortion or lean due to elevation. Bridges and elevated roads have been checked for distortion and corrected as needed. Each orthorectified pixel is exactly 0.25 ft. square. This orthophoto product conforms to American Society for Photogrammetry and Remote Sensing (ASPRS) Class I Standards for 1"=50' horizontal mapping or current ASPRS Positional Accuracy Standards for Digital Geospatial Data for Standard Mapping product where Horizontal Accuracy at the 95% Confidence Level is less than or equal to 2 pixels. Project coordinate systems were established on the Texas State Plane North Central Zone 4202 projection, with horizontal datum referenced to the North American Datum of 1983 (NAD83), and vertical datum to the North American Vertical Datum of 1988 with units of U.S. Survey Feet.
  1. How might this data set be cited?
    Bohannan Huston, Inc., 20150923, Lubbock 2015 Digital Orthophotography: Lubbock Digital Orthophotography Project RGB with color infrared (CIR) four band (4) digital orthoimagery (DOI), City of Lubbock, 1625 13th Street Lubbock, Texas 79401.

    Online Links:

    Other_Citation_Details:
    This dataset was created as a joint effort between the City of Lubbock, Bohannan Huston, Inc. and Aero-Graphics, Inc. in support of the City of Lubbock Geographic Information Systems’ mission. The data is owned by the City of Lubbock.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -102.094465
    East_Bounding_Coordinate: -101.683301
    North_Bounding_Coordinate: 33.758523
    South_Bounding_Coordinate: 33.421434
  3. What does it look like?
    op_browse_graphic.png (portable network graphic)
    View of natural color project orthophoto mosaic.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 10-Mar-2015
    Ending_Date: 14-Mar-2015
    Currentness_Reference: ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: GeoTIFF
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 475,200 x 485,760, type Pixel 0.25
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: NAD 1983_StatePlane_Texas_North_Central_FIPS_4202_Feet
      State_Plane_Coordinate_System:
      SPCS_Zone_Identifier: Texas_North_Central_FIPS_4202
      Lambert_Conformal_Conic:
      Standard_Parallel: 32.133333
      Standard_Parallel: 33.966667
      Longitude_of_Central_Meridian: -98.5
      Latitude_of_Projection_Origin: 31.66666666666667
      False_Easting: 196855.0
      False_Northing: 6561666.666666666
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 0.25
      Ordinates (y-coordinates) are specified to the nearest 0.25
      Planar coordinates are specified in U.S. Survey Feet
      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.001 GPS position and orientation system
      Altitude_Distance_Units: U.S. Survey Feet
      Altitude_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?
    value
    4-band true color and near infrared orthoimagery is organized in four bands or channels which represent the red, green, blue, and near infrared (R,G,B,IR) portions of the electromagnetic spectrum. Each image pixel is assigned a triplet of numeric values, one for each band stored as 8-bit image data with 256 gray levels ranging from 0 to 255 for each band. (Source: U.S. Department of the Interior, U.S. Geological Survey, 1996, Standards for Digital Orthophotos: Reston, Va.)
    value
    gray-scale (Source: Radiometric image brightness values generated during orthophoto processing.)
    ValueDefinition
    255no data
    Entity_and_Attribute_Overview:
    For color-infrared and natural color image composites, a digital number from 0 to 255 will also be assigned to each pixel and for each band in a three-band image represented by red, green, and blue, (natural color composite - RGB) or infrared, red and green (as RGB for a false color-infrared (CIR) composite). Areas where the rectification process is incomplete because of incomplete data (that is, lack of image data) are represented as white or 255 in all three bands.
    Entity_and_Attribute_Detail_Citation:
    http://nationalmap.gov/standards/pdf/6META997.PDF National Mapping Program Technical Instructions U.S. Department of the Interior U.S. Geological Survey National Mapping Division Part 6 Digital Orthophoto Quadrangles Standards for the Preparation of Digital Geospatial Metadata

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    Acknowledgement of the City of Lubbock, TX GIS & Data Services Department, Bohannan Huston, Inc. and Aero-Graphics, Inc. would be appreciated for products derived from these data. Data is owned by the City of Lubbock.
  3. To whom should users address questions about the data?
    City of Lubbock
    Attn: Sally Still Abbe
    Director, GIS and Data Services
    PO Box 2000
    Lubbock, Texas
    USA

    806-775-2106 (voice)
    gisanddataservices@mylubbock.us

Why was the data set created?

The purpose of this project is to support activities throughout the City of Lubbock, including but not limited to Geographic Information Systems data maintenance, urban, community and regional planning; project and infrastructure planning; project reporting; floodplain mapping; stormwater management; vegetation analysis; change detection; and initial project reviews.

How was the data set created?

  1. From what previous works were the data drawn?
    Lubbock Control Report SIGNED 2015-06-02.pdf (source 1 of 2)
    Bohannan Huston, Inc.; Alan R. Benham, P.S., June 2, 2015, Survey Control Report for Lubbock Orthophotography.

    Type_of_Source_Media: Portable Document Format
    Source_Scale_Denominator: 240
    Source_Contribution:
    Geodetic control were established for the project to provide a primary control network for orthophotography mapping in the project coordinate system.
    (source 2 of 2)
    Inc., Aero-Graphics, 20150312, Airborne Collection - Microsoft/Vexcel UltraCam Eagle (UCE) digital camera system with Inertial Measurement Unit (IMU) and on-board Global Positioning System (GPS).on-board Global Positioning System (GPS)..

    Type_of_Source_Media: Hard drive
    Source_Scale_Denominator: 600
    Source_Contribution:
    Digital aerial imagery was collected at a nominal average altitude of 9,466 ft above ground level (AGL) using the Microsoft/Vexcel UltraCam Eagle (UCE) digital camera system. The UCE aerial imagery served the purpose of supporting the production of 3-inch ground sample distance (GSD) resolution digital orthoimagery.
  2. How were the data generated, processed, and modified?
    Date: Apr-2015 (process 1 of 4)
    1. Aerial Triangulation - Images were aerotriangulated to finalize their exterior orientation (EO). Intergraph ISAT and GeoMedia Professional were used to perform digital point matching/mensuration/block adjustments and quality control queries respectively. Final block adjustments were evaluated at sub-pixel accuracy.
    Date: Jun-2015 (process 2 of 4)
    2. Orthorectification - Images were orthorectified to remove distortions caused by changes in the elevation of the terrain, camera orientation and lens distortion. The orthorectification process used a cubic convolution interpolation method and ground elevations sampled from prior project 2010 LiDAR bare-earth surface digital elevation models (DEM). Orthorectified areas not covered by existing LiDAR were autocorrelated rectified to autocorrelated surface data generated from the 2015 aerial imagery. Intergraph ImageStation OrthoPro® software used was for orthorectification.
    Date: Jun-2015 (process 3 of 4)
    3. Orthomosaic - Images were color balanced and color corrected individually to ensure color consistency between flight lines, time(s) of day, and date(s) of capture. Images were mosaicked into large aggregate tiles and automatic seamlines were used to combine the most nadir components of individual images. Aggregate tiles were again tonally balanced and color corrected with the entire project in view. A second global color adjustment was performed to minimize color changes across images. Project deliverable tiles were cut from the mosaic and formatted for delivery. Trimble OrthoVista® software was used to perform these steps.
    Date: Jul-2015 (process 4 of 4)
    4. Orthophoto Quality Control (QC) and Delivery. Review processes were developed to comprehensively assess output orthophoto data tiles. This process was designed to identify any areas requiring additional effort to correct issues in automatic seam line placement and/or orthorectification (and bridge warping in particular). During this assessment, all orthophoto tiles were reviewed by analysts in GeoMedia Professional®. Issues requiring additional work were flagged using a “call” feature indicating the type of fix required. Next, specific rework sites were reprocessed with Adobe Photoshop® to remedy issues identified by call features. Final review of all fixed tiles was performed by an independent analyst to verify (Quality Assurance) that the call was corrected as required. Final QC data tiles were then processed for delivery to include production of compressed (GeoTIFF, MrSid, and ECW format) and uncompressed (GeoTIFF) tiles.
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Radiometric qualities of the imagery have been inspected and color balancing processing applied to create near seamless imagery mosaics. Slight radiometric differences may exist between adjacent orthorectified photos. Radiometric differences may be attributable to changes in time and date of source image acquisition and sun angles differences along flight lines. To minimize these variations image flight acquisition adhered to ASPRS capture standards requiring at least a 30 degree sun angle above horizon for all flights. Tonal balancing was also performed during image mosaicking to adjust and optimize color matching between adjacent photos.
  2. How accurate are the geographic locations?
    Tested 0.23 ft. horizontal accuracy (NSSDA) to well-defined primary aerial photography control. Independent accuracy testing of reasonably defined photo ID features tested to 0.50 feet horizontal accuracy.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Deliverable data tiles were inspected to ensure complete image data coverage. Data tiles may be comprised of multiple flight line data sources. Sources covering the orthophoto mosaic tiles are defined by flight line photo index information. The resulting digital orthophoto image (DOI) tile is a square.
  5. How consistent are the relationships among the observations, including topology?
    Orthophoto tiles have been validated for image file/pixel size and inspected visually to ensure logical relationships between expected data elements.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: Access to this data set is provided by the City of Lubbock.
Use_Constraints:
Neither City of Lubbock, nor Bohannan Huston, Inc. (BHI) assumes liability for misuse of the data. Data should be used at the scale for which they were intended. No warranty, expressed, or implied, is made by the City of Lubbock nor BHI regarding the utility of the data on any other system, nor shall the act of distribution constitute such warranty. THIS PUBLICATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE CITY OF LUBBOCK SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RELATED TO THE USE OF THIS PUBLICATION, WHETHER OR NOT THE CITY OF LUBBOCK IS ADVISED OF SUCH DAMAGE.
  1. Who distributes the data set? (Distributor 1 of 1)
    Contact_Organization
    City of Lubbock; Sally Still Abbe; Director, GIS and Data Services
    P.O. Box 2000
    Lubbock, TX
    USA

    (806) 775-2106 (voice)
    gisanddataservices@mylubbock.us
  2. What's the catalog number I need to order this data set? digital orthoimagery (DOI)
  3. What legal disclaimers am I supposed to read?
    Distribution_Liability: The City of Lubbock, Texas, is furnishing these geographic data on an "as is" basis, and makes no guarantee, representation or warranty concerning the accuracy or completeness of information contained in the geographic data. The City of Lubbock further makes no guarantees, representations or warranties, either expressed or implied, as to any other matter whatsoever concerning the data and product, including, without limitation, the condition of the product, or its fitness for any particular use or purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers of Bohannan Huston, Inc. (BHI) and served by the City of Lubbock, no guarantee, representation or warranty, either expressed or implied, is made regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such guarantee, representation or warranty. In no event shall the City of Lubbock or BHI have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support. THIS PUBLICATION IS PROVIDED BY THE CITY OF LUBBOCK "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE CITY OF LUBBOCK SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RELATED TO THE USE OF THIS PUBLICATION, WHETHER OR NOT THE CITY OF LUBBOCK IS ADVISED OF SUCH DAMAGE.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 2015
Metadata author:
Bohannan Huston, Inc.
Attn: Dennis Sandin
Sr. Vice President Geospatial Operations
7500 Jefferson St. NE
Albuquerque, NM
USA

800-877-5332 (voice)
505-798-7932 (FAX)
dsandin@bhinc.com
Hours_of_Service: Monday - Thursday 07:30am - 5:30pm; Friday 07:30am - 12:00pm
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Generated by mp version 2.9.32 on Wed Jan 06 15:29:34 2016