Remote Sensing Week 13: Accuracy & Classification
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What does accuracy refer to in the context of remote sensing?

  • The level of detail of the measurement
  • The proportion of agreement between a classified map and the reference data (correct)
  • The thematic precision of the mapped data
  • The spatial resolution of the data set

    • What type of accuracy refers to how well the class name on the map corresponds to what is really on the ground?

  • Spatial Accuracy
  • Thematic Accuracy (correct)
  • Precision
  • Map Accuracy

    • What is the term for the data collected in the field to assess accuracy?

  • Spatial Data
  • Ground-Truth Data (correct)
  • Reference Data
  • Thematic Data

    • What is the relationship between accuracy and precision?

    <p>There is an inverse relationship between them</p> Signup and view all the answers

    What is spatial accuracy related to?

    <p>The spatial resolution of the data set</p> Signup and view all the answers

    What is an example of a map with high thematic precision?

    <p>A map distinguishing Lodgepole pine, Douglas fir, Ponderosa</p> Signup and view all the answers

    What is a potential drawback of using reference data in geospatial analysis?

    <p>It may not accurately represent the actual conditions on the ground.</p> Signup and view all the answers

    What is the purpose of comparing the classified data to the reference data?

    <p>To determine the accuracy of the classification.</p> Signup and view all the answers

    What type of array is used to create an error matrix?

    <p>An (n x n) array.</p> Signup and view all the answers

    What do the columns in an error matrix represent?

    <p>The reference data or the data that is known to be true or correct.</p> Signup and view all the answers

    What is the purpose of an error matrix?

    <p>To calculate a variety of accuracy metrics.</p> Signup and view all the answers

    In the example provided, how many reference sites were sampled in the field to verify the land cover type?

    <p>95</p> Signup and view all the answers

    What is the primary goal of stratified random sampling?

    <p>To ensure larger area classes receive more sampling points</p> Signup and view all the answers

    What is the ideal way to collect reference data?

    <p>Conducting field collection, also known as ground-truthing</p> Signup and view all the answers

    What is the advantage of using high-resolution reference imagery?

    <p>It is relatively inexpensive and generally faster than field collection</p> Signup and view all the answers

    What is the purpose of using high-resolution remotely sensed data?

    <p>To assess the accuracy of low-resolution data</p> Signup and view all the answers

    What is the benefit of using stratified random sampling in areas with varying class sizes?

    <p>It ensures that classes with a larger area receive more sampling points, while smaller area classes still have sampling points</p> Signup and view all the answers

    What is the formula to calculate the overall accuracy?

    <p>Number of correctly classified sites / Total number of reference sites</p> Signup and view all the answers

    What is the advantage of using field collection for collecting reference data?

    <p>It is the preferred method to obtain reference data</p> Signup and view all the answers

    What is the relationship between error and accuracy?

    <p>Error + Accuracy = 100%</p> Signup and view all the answers

    What type of error occurs when a reference site is left out from the correct class in the classified map?

    <p>Error of Omission</p> Signup and view all the answers

    What is the term for the accuracy from the point of view of a map user?

    <p>User's Accuracy</p> Signup and view all the answers

    How is the error of omission calculated?

    <p>By reviewing the reference sites for incorrect classifications</p> Signup and view all the answers

    What is the term for the accuracy from the point of view of the mapmaker?

    <p>Producer's Accuracy</p> Signup and view all the answers

    What is the Producer's Accuracy a measure of?

    <p>The number of correctly classified reference sites divided by the total number of reference sites</p> Signup and view all the answers

    What is the relationship between the Producer's Accuracy and the Omission Error?

    <p>The Producer's Accuracy is the difference between 100% and the Omission Error</p> Signup and view all the answers

    What does the User's Accuracy represent?

    <p>The reliability of the map from the user's point of view</p> Signup and view all the answers

    How is the User's Accuracy calculated?

    <p>By taking the total number of correct classifications and dividing it by the row total</p> Signup and view all the answers

    What is the Commission Error?

    <p>The number of incorrectly classified sites divided by the total number of classified sites</p> Signup and view all the answers

    What is the relationship between the User's Accuracy and the Commission Error?

    <p>The User's Accuracy is the difference between 100% and the Commission Error</p> Signup and view all the answers

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