One-Foot Resolution Black & White Digital Orthophotography 2010, Dane County (WI)

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Frequently-anticipated questions:


What does this data set describe?

Title:
One-Foot Resolution Black & White Digital Orthophotography 2010, Dane County (WI)
Abstract:
The Fly Dane 2009/2010 one-foot resolution digital orthophotos are a raster mosaicked data set developed from color digital aerial imagery. The digital aerial imagery was acquired in the spring of 2010 to create 1"=200' scale digital orthophotos with one-foot ground resolution covering all of Dane County. The digital imagery was obtained during leaf off conditions, with little or no snow on the ground.
  1. How should this data set be cited?

    Dane County Land Information Office and Fly Dane Partnership, 20110131, One-Foot Resolution Black & White Digital Orthophotography 2010, Dane County (WI): Dane County Land Information Office, Madison, WI.

    Online Links:

    • \\data\lio$\Documents\METADATA\Dane County\xml\OrthoBW1Foot2010

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -89.842242
    East_Bounding_Coordinate: -89.007099
    North_Bounding_Coordinate: 43.295024
    South_Bounding_Coordinate: 42.825679

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 26-Mar-2010
    Ending_Date: 29-Mar-2010
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: SDE 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: None
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 12000 x 12000 x 1, type Pixel

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 43.069516
      Standard_Parallel: 60.000000
      Longitude_of_Central_Meridian: -89.422222
      Latitude_of_Projection_Origin: 43.069516
      False_Easting: 811000.000000
      False_Northing: 480943.886000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 1.000000
      Ordinates (y-coordinates) are specified to the nearest 1.000000
      Planar coordinates are specified in survey feet

      The horizontal datum used is D_North_American_1983_HARN.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 1.000000
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Each pixel in the digital image contains a value representing relative brightness or radiance(0-255 for this 8-bit imagery.) Each pixel represents a 1 square foot ground area.
    Entity_and_Attribute_Detail_Citation: Not available


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?

  3. To whom should users address questions about the data?

    Dane County Land Information Office
    c/o Fred Iausly
    Senior GIS Analyst
    210 Martin Luther King Jr. Blvd; Room 339
    Madison, WI 53703
    USA

    (608) 266-4398 (voice)
    (608) 266-1242 (FAX)
    iausly@countyofdane.com

    Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
    Contact_Instructions:
    Additional Contact Persons: Tim Confare (Senior GIS Analyst) (608) 267-1598 Dave Watson (Senior GIS Systems Administrator) (608) 266-4265


Why was the data set created?

These data are used for a number of purposes including base mapping, selection of photo-identifiable features, registration and adjustment of other vector data sets, onscreen digitizing and as an image backdrop for mapping, exhibits and informational materials. The development of the orthophotography also resulted in the production of a road centerline file, drainage vectors, and building footprint polygons.


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 2)
    Associates, Ayres, Unpublished Material, Dane County (WI) 2010 1:20000 Scale Black & White Aerial Photography:.

    Source_Scale_Denominator: 20000
    Source_Contribution:
    The imagery was collected at an altitude of 9,600 feet using a Digital Mapping Camera (DMC) sensor. The DMC sensor collects twelve bit image data which requires radiometric adjustment for output in standard eight bit image channels.

    Dane County (WI) DTM (source 2 of 2)
    Associates, Ayres, Unpublished Material, Dane County (WI) 2009 Digital Terrain Model.

    Source_Scale_Denominator: 1200
    Source_Contribution:
    Ayres Associates, Madison, WI, under contract to Dane County, WI, updated a DTM as part of the Fly Dane 2009 project.

  2. How were the data generated, processed, and modified?

    Date: 2010 (process 1 of 4)
    Ground control consisted of photo identifiable surveyed points and panels. The imagery was collected at an altitude of 9,600 feet using a DMC sensor. Image quality was verified during the post flight review phase. Factors considered during this review included but were not limited to the presence of smoke and/or cloud cover, contrails, light conditions and sun glint. The triangulated strips were rectified to an elevation model that Ayres developed for this project using lidar data developed for Fly Dane 2010. The red, green and blue bands were combined to generate a final orthophoto. The DMC sensor collects twelve bit image data which requires radiometric adjustment for output in standard eight bit image channels. Converting to eight bit results in a reduction of the color range from 4096 to 256 - thus loss of radiometric detail is inevitable. The extra dynamic range of the sensor permits greater object differentiation in shadows and in bright areas. The sixteen bit dynamic range permitted the imagery to be more effectively color balanced than is possible with eight bit imagery. This was accomplished by performing tonal enhancements immediately prior to the reduction from sixteen bit to eight bit data. In addition to color balancing these eight bit images were adjusted to create seamless imagery to the highest extent practically achievable. The imagery was mosaicked using a combination of automated and manual seam lines generation. Project specified tiles were extracted from the mosaic. Final image tiles were reviewed for artifacts and anomalies and adjusted as part of quality control procedures. Adjacent images are compared for consistency in overlap regions. The images are reviewed for rectification problems such as bridge displacements caused by the underlying digital elevation model. When necessary, local corrections to the imagery were performed to minimize such effects. After production was completed, the color orthoimagery was processed to grayscale. Grayscale values (0-255) were assigned to each pixel based upon its blue/green/red color values. The imagery was then adjusted a final time to assure even brightness and contrast.

    Person who carried out this activity:

    Ayres Associates
    1802 Pankratz St
    Madison, WI 53704-4069
    USA

    (608) 443-1200 (voice)
    (608) 443-1250 (FAX)

    Hours_of_Service: Normal Business Hours (8::00am - 5::00pm)
    Date: 12-Jan-2011 (process 2 of 4)
    Dataset copied.

    Data sources used in this process:

    • H:\Documents\METADATA\Dane County\xml\OrthoBW1Foot2010

    Date: 10-Jun-2011 (process 3 of 4)
    Dataset copied.

    Data sources used in this process:

    • J:\Orthos2010\Metadata\OrthoBW1Foot2010

    Date: 13-Jun-2011 (process 4 of 4)
    Dataset copied.

    Data sources used in this process:

    • H:\Documents\METADATA\Dane County\FD2010Metadata\OrthoBW1Foot2010

  3. What similar or related data should the user be aware of?

    Dane County Land Information Office and Fly Dane Partnership, 20110131, One-Foot Resolution Color Digital Orthophotography 2010, Dane County (WI): Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20110131, One-Foot Resolution Color Infrared Digital Orthophotography 2010, Dane County (WI): Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20090315, One-Foot Vertical Digital Elevation Model 2009, Dane County (WI): Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20110131, Five-Meter Resolution Black & White Digital Orthophotography 2010, Dane County (WI): Dane County Land Information Office, Madison, WI.


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

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    Data associated with this ortho project was developed using processed design to meet American Society for Photogrammetry and Remote Sensing Class II standards for 1"=200' scale mapping (or 1:2,400). The horizontal accuracy is +/- 6.6 feet for well-defined points, at a ninety percent confidence level.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    The digital images cover all of Dane County, WI, and are divided into 315 four square mile tiles with no gaps or omissions.

  5. How consistent are the relationships among the observations, including topology?

    This imagery is a mosaicked raster data set. Each pixel in the digital image contains a value representing relative brightness or radiance (0-255 for this 8-bit imagery.) Each pixel represents a 1 square foot ground area.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: Data is copyright and licensed for use.
Use_Constraints:
Refer to the License Agreement for Dane County Digital Geographic Data Sets. <http://www.co.dane.wi.us/lio/gis/licenseaggreement.pdf>

  1. Who distributes the data set? (Distributor 1 of 1)

    Dane County Land Information Office
    c/o Tim Confare
    Senior GIS Analyst
    210 Martin Luther King Jr. Blvd; Room 339
    Madison, WI 53703
    USA

    (608) 267-1598 (voice)
    (608) 266-1242 (FAX)
    confare@countyofdane.com

    Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
    Contact_Instructions:
    Additional Contact Persons:: Fred Iausly (Senior GIS Analyst) (608) 266-4398 Dave Watson (Senior GIS Systems Administrator) (608) 266-4265
  2. What's the catalog number I need to order this data set?

    One-Foot Resolution Black & White Digital Orthophotography 2010

  3. What legal disclaimers am I supposed to read?

    The burden for determining 'fitness for use' rests entirely upon the requester/Licensee. Dane County and its co-producers will not be liable in any way for accuracy of the data or for uses other than intended. Dane County assumes no responsibility whatsoever for direct, indirect, special, consequential, exemplary or other damages. Licensee agrees to indemnify, hold harmless and defend Dane County, its employees, agents, representatives and co-producers from any claims, damages, liabilities and expenses arising from Licensee's use of licensed data sets or products derived there from.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    An additional cost of $60/hour for staff time plus computer time and media charges is assessed for non-standard datasets or non-standard data file formats. Prices are subject to change without notice. See Price/Product list for more information, <http://www.co.dane.wi.us/lio/datacatalog.asp>. Data can be order online using the Dane County's On-line GIS Data Order System, <http://www.co.dane.wi.us/lio/digital_order.asp>. Acceptance of the License Agreement for Dane County Digital Geographic Data Sets must be received before data can be released. All requests will be invoiced following delivery of the data.


Who wrote the metadata?

Dates:
Last modified: 12-Jan-2011
Last Reviewed: 20-Feb-2006
Metadata author:
Dane County Land Information Office
c/o Fred Iausly
Senior GIS Analyst
210 Martin Luther King Jr. Blvd; Room 339
Madison, WI 53709
USA

(608) 266-4398 (voice)
(608) 266-1242 (FAX)
iausly@countyofdane.com

Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
Contact_Instructions:
Additional Contact Persons: Tim Confare (Senior GIS Analyst) (608) 267-1598 Dave Watson (Senior GIS Systems Administrator) (608) 266-4265
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.6 on Mon Jun 13 13:54:40 2011