Dane County (WI) 2005 One-Foot Resolution Digital Orthophotography

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Frequently-anticipated questions:


What does this data set describe?

Title:
Dane County (WI) 2005 One-Foot Resolution Digital Orthophotography
Abstract:
The Fly Dane 2005 one-foot resolution digital orthophotos are a raster mosaicked data set derived from black and white aerial photographs. The aerial photography was acquired in the spring of 2005 to create 1"=200' scale digital orthophotos with one-foot ground resolution covering all of Dane County.
  1. How should this data set be cited?

    Dane County Land Information Office and Fly Dane Partnership, 20060317, Dane County (WI) 2005 One-Foot Resolution Digital Orthophotography: Dane County Land Information Office, Madison, WI.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -89.84663
    East_Bounding_Coordinate: -88.98861
    North_Bounding_Coordinate: 43.29968
    South_Bounding_Coordinate: 42.84499

  3. What does it look like?

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

    Calendar_Date: 08-Apr-2005
    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: None
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 11363 x 11280 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: 43.230556
      Standard_Parallel: 42.908333
      Longitude_of_Central_Meridian: -89.422222
      Latitude_of_Projection_Origin: 41.75
      False_Easting: 247193.294400
      False_Northing: 0

      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 User_Defined_Datum.
      The ellipsoid used is User_Defined_Spheroid.
      The semi-major axis of the ellipsoid used is 6378407.621.
      The flattening of the ellipsoid used is 1/298.2698770.

  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 360
    Madison, WI 53703
    USA

    (608) 266-4398 (voice)
    (608) 266-1242 (FAX)
    iausly@co.dane.wi.us

    Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
    Contact_Instructions:
    Additional Contact Persons: Tim Confare (Senior GIS Analyst) (608) 267-1598, Diann Danielsen (Land Information Office Manager) (608) 266-4942


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 digital terrain model (DTM), road centerline file, drainage vectors, and 2-foot and 4-foot contours.


How was the data set created?

  1. From what previous works were the data drawn?

    Dane County 2005 AP (source 1 of 2)
    Associates, Ayres, Unpublished Material, Dane County (WI) 2005 1:20000 Scale BW Aerial Photography:.

    Source_Scale_Denominator: 20000
    Source_Contribution:
    The photo diapositives were digitally scanned at 15 microns and photogrammetrically processed to produce the final imagery and products.

    Dane County (WI) DTM (source 2 of 2)
    Associates, Ayres, Unpublished Material, Dane County (WI) 2005 Digital Terrain Model.

    Source_Scale_Denominator: 2400
    Source_Contribution:
    Ayres Associates, Madison, WI, under contract to Dane County, WI, updated a DTM as part of the Fly Dane 2005 project.

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

    Date: 2005 (process 1 of 2)
    The aerial photography was acquired April 8, 2005. The aerial photography was scanned at a 15 micron resolution. A ground solution was generated via digital photogrammetric aerotriangulation based upon an established ground survey network. The aerial photography was then rectified to the updated Digital Terrain Model. The rectified imagery underwent tone balancing and density matching to provide a seamless digital mosaic and edge-matching to assure no gaps or spatial shifts between adjoining images. Manual edits were made to eliminate film artifacts, spatial distortion of select above-ground features particularly bridges. Preliminary imagery was saved out in GeoTIFF file with an associated World File (tfw). The preliminary imagery was sent to the client for reviewed. After the preliminary imagery was accepted by the client, final GeoTIFFS were processed out and delivered.

    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: 2005 (process 2 of 2)
    Dane County Land Information Office performed a Quality Assurance review of the preliminary rectified imagery. Each tile was reviewed at 1;2,400 scale. The imagery was reviewed for scratches and dust spots, contract issues, tonal difficulties, bridge distortions, road distortions, ghosting and black holes. Errors were saved to a shapefile and sent to the contractor for correction. The corrected imagery was then sent to the county for a second review. When all the corrections have been made the county approved the imagery.

    Person who carried out this activity:

    Dane County Land Information Office
    c/o Fred Iausly
    Senior GIS Analyst
    210 Martin Luther King Jr. Blvd, Room 360
    Madison, WI 53703
    USA

    (608) 266-4398 (voice)
    (608) 266-1242 (FAX)
    iausly@co.dane.wi.us

    Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
    Contact_Instructions:
    Additional Contact Persons: Tim Confare (Senior GIS Analyst) (608) 267-1598, Diann Danielsen (Land Information Office Manager) (608) 266-4942
  3. What similar or related data should the user be aware of?

    Dane County Land Information Office and Fly Dane Partnership, 20060317, Dane County (WI) 2005 Six-Inch Resolution Digital Orthophotography: Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20060407, Dane County (WI) 2005 Digital Four-Foot Contours: Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20060407, Dane County (WI) 2005 Two-Foot Vertical Digital Elevation Model: Dane County Land Information Office, Madison, WI.

    Dane County Land Information Office and Fly Dane Partnership, 20060407, Dane County (WI) 2005 Digital Two-Foot Contours: Dane County Land Information Office, Madison, WI.

    This is part of the following larger work.

    .

    Dane County Land Information Office and Fly Dane Partnership, 20060324, Dane County (WI) 2005 Five-Meter Resolution Digital Orthophotography: 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?

    The data set meets the National Map Accuracy Standards for the scale 1:2,400 (or 1"=200'). The horizontal accuracy is +/- 6.6 feet for well-defined points, at a ninety percent confidence level. (Fly Dane 2005 Digital Orthophotography Accuracy Report, Ayres Associates).

  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 Fred Iausly
    Senior GIS Analyst
    210 Martin Luther King Jr. Blvd; Room 520
    Madison, WI 53703
    USA

    (608) 266-4398 (voice)
    (608) 266-1242 (FAX)
    iausly@co.dane.wi.us

    Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
    Contact_Instructions:
    Additional Contact Persons:: Tim Confare (Senior GIS Analyst) (608) 267-1598, Diann Danielsen (Land Information Office Manager) (608) 266-4942
  2. What's the catalog number I need to order this data set?

    UxxxttFDD9 (xxx refers to the survey township and range designation. For example 506 = T05N R06E. tt refers to the tile 1 thru 9 within the township). For more information on tiling and coverage area see <http://www.co.dane.wi.us/lio/flydane.asp>, Fly Dane 2005.

  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 $30/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. For a list of Products/ Prices see <http://www.co.dane.wi.us/lio/datacatalog.asp>. Data can be order online using the Dane County GIS Data Order Form, <http://www.co.dane.wi.us/lio/Gis/townbundle.htm>. Fill out the online License Agreement for Dane County Digital Geographic Data Sets <http://www.co.dane.wi.us/lio/Gis/licenseaggreement.pdf>, providing licensing information and custom data requested. Mail or fax in the license agreement. A signed license agreement 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: 16-Mar-2006
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 360
Madison, WI 53709
USA

(608) 266-4398 (voice)
(608) 266-1242 (FAX)
iausly@co.dane.wi.us

Hours_of_Service: Normal Business Hours (8:00am - 4:30pm)
Contact_Instructions:
Additional Contact Persons: Tim Confare (Senior GIS Analyst) (608) 267-1598, Diann Danielsen (Land Information Office Manager) (608) 266-4942
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.8.6 on Thu Mar 16 15:05:23 2006