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U.S. DEPARTMENT OF THE INTERIOR

BUREAU OF LAND MANAGEMENT

Oregon / Washington

GIS Metadata


BLM OR Aerial Photography Flightlines Line

Frequently-asked questions:


What does this data set describe?

Title:
BLM OR Aerial Photography Flightlines Line

Abstract:
ap_flightlines_arc: This line dataset depicts the flightlines of aerial photography taken over BLM lands in Oregon and Washington. This is subject to update at a future point.

Supplemental information:
This feature is intended to facilitate the location and identification of BLM flightline data for release to BLM district personnel, other agencies and the general public.

  1. How should this data set be cited?

    Bureau of Land Management, Oregon/Washington State Office, 20100101, BLM OR Aerial Photography Flightlines Line.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -125
    East: -116
    North: 49.5
    South: 41.5

  3. What does it look like?

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

    Beginning date: 19540701
    Ending date: 20130831
    Currentness reference:
    publication date

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

    Geospatial data presentation form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (14037)
      • String (14037)

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

  7. How does the data set describe geographic features?

    AP_Flightlines_Arc
    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    Shape_Length
    Length of feature in internal units. (Source: ESRI)
                      

    Positive real numbers that are automatically generated.

    Roll
    Number assigned to the film roll. (Source: BLM)
                      

    Flight
    The number assigned to the flight line.  Historically, R was used for reflights, G was used for Gap flights.  Flightline segments, after 1998, were numbered with decimals (14.0, 14.1, 14.2, etc.). (Source: BLM)
                      

    Proj_name
    Project code used as a unique identifier. (Source: BLM)
                      

    District
    BLM District project is located within. (Source: BLM)
                      

    Length_Mi
    Length of each line of flight in miles. Distance was calculated in UTM. (Source: BLM)
                      

    Drainage
    Alphanumeric code given to centers on flightlines that capture streams. Drainage codes are specific to a given reach within a given project. Different projects may share the same drainage values. Different flightlines over the same reach within the same project will share the same drainage value. Different reaches within the same project will have different values. (Source: BLM)
                      

    Stream_Name
    Stream Name along which flightline is coincident.

    Entity and attribute overview:
    Flight lines are in an arc feature class, created from digital files by connecting photocenters.

    Entity and attribute detail citation:
    Since 2001, contractors have collected GPS photo centers at the instant of exposure and provided them in digital form.  Where GPS obtained photo centers were not available, BLM scanned mylar or paper indexes and registered them to a projection before digitizing the photo centers.  In some cases, BLM digitized every fifth photo center and allowed a software program to interpolate the positions of the photo centers in between.  Those photo points are identified as "I" in the "Type" field of the attributes.
    
    Although BLM cannot verify, in each individual case, how historical indexes were made, it is presumed that the contractor who flew the photography identified the photo center positions and marked them on a mylar or paper map.
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Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

    • Bureau of Land Management, Oregon/Washington State Office

  2. Who also contributed to the data set?

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

    Corey Plank
    Bureau of Land Management
    Lead Cartographer
    P.O. Box 2965
    Portland, OR 97204
    US

    (503) 808-6145 (voice)
    cplank@blm.gov
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Why was the data set created?

This feature class assists in the location of aerial imagery.

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How was the data set created?

  1. Where did the data come from?

    Type of source media: onLine
    Source contribution:
    Photocenters

  2. What changes have been made?

    Date: unknown (change 1 of 3)
    The flight lines were created by BLM employees who connected the dots of the photocenters in order to more easily see where flight line segments began, ended, or overlapped.

    Person responsible for change:
    Susan Nelson
    Bureau of Land Management
    Cartographer/Remote Sensing Acquisition
    P.O. Box 2965
    Portland, OR 97204
    US

    (503) 808-6139 (voice)
    s1nelson@blm.gov

    Date: 20120423 (change 2 of 3)
    Field names were standardized (given common names). Data was projected to GCS North American 1983 Datum. Individual flightline data were appended from individual project files to a line feature class.

    Person responsible for change:
    Eric Hiebenthal
    Bureau of Land Management, Oregon State Office
    GIS Data Management Specialist
    P.O. Box 2965
    Portland, OR 97208
    US

    503-808-6565 (voice)
    503-808-6419 (FAX)
    ehiebent@blm.gov

    Date: 20130925 (change 3 of 3)
    Inclusion of data from the recent imagery over the Douglas Complex and Big Windy Fires.

    Person responsible for change:
    Corey Plank
    Bureau of Land Management
    Lead Cartographer
    P.O. Box 2965
    Portland, OR 97208
    US

    (503) 808-6145 (voice)
    cplank@blm.gov

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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?

    Flightlines connect photo centers so are only as accurate as the photo centers. 90% of the centerpoints are within 400 feet of their actual position.

  3. How accurate are the heights or depths?

    Not applicable.

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

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

    Not Applicable

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How can someone get a copy of the data set?

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

Access constraints: PUBLIC DATA: None, these data are considered public domain.
Use constraints:
These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived, and both scale and accuracy may vary across the data set. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of the metadata file associated with these data. These data are neither legal documents nor land surveys, and must not be used as such. Official records may be referenced at most BLM offices. Please report any errors in the data to the BLM office for which it was obtained. The BLM should be cited as the data source in any products derived from these data. Any Users wishing to modify the data should describe the types of modifications they have performed. The User should not misrepresent the data, nor imply that changes made were approved or endorsed by BLM. This information may be updated without notification.

Distributor 1 of 1

  1. Who distributes the data set?

    Eric Hiebenthal
    Bureau of Land Management, Oregon State Office
    GIS Data Management Specialist
    P.O. Box 2965
    Portland, OR 97208
    US

    503-808-6565 (voice)
    503-808-6419 (FAX)
    ehiebent@blm.gov

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    The BLM assumes no responsibility for errors or omissions. No warranty is made by the BLM as to the accuracy, reliability, or completeness of these data for individual use or aggregate use with other data; nor shall the act of distribution to contractors, partners, or beyond, constitute any such warranty for individual or aggregate data use with other data. Although these data have been processed successfully on computers of BLM, no warranty, expressed or implied, is made by BLM regarding the use of these data on any other system, or for general or scientific purposes, nor does the fact of distribution constitute or imply any such warranty. In no event shall the BLM 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 the use or reliance on the geographic data or arising out of the delivery, installation, operation, or support by BLM.

  4. How can I download or order the data?

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

  6. What hardware or software do I need in order to use the data set?

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Who wrote the metadata?

Dates:
Last modified: 20120503
Last reviewed: 20131021

Metadata author:
Roger Mills
Bureau of Land Management, Oregon State Office
GIS Spec
P.O. Box 2965
Portland, OR 97208
US

(503) 808-6340 (voice)
(503) 808-6419 (FAX)
r2mills@blm.gov

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata(FGDC-STD-001-1998)

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