LAND COVER INVESTIGATION

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LAND COVER INVESTIGATION
Mapping
Data Collection
Manual and Computer-aided Mapping and Change Over
Time Protocols
Land Cover Sample Site and Biometry Protocols
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LAND COVER INVESTIGATION

• Collect MANY Land Cover Sample Sites.
• Map your GLOBE Study Site using the data and
  topographic maps, aerial photos, etc. with manual
  mapping or computer-aided mapping.
• Carry out an accuracy assessment.
• Analyze change in two images several years apart.

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USING GPS IN A LAND COVER SAMPLE SITE
We need to compare each Land Cover Sample Site on
the ground to the corresponding area on the image.

• If we take the average of 5 minutes of GPS
  readings, our position is accurate to about 5m.
• It is impossible to determine the exact corner
  location of a single pixel on the ground.
• By collecting GPS data in the center of the site,
  we know that within the positional accuracy of
  the imagery and ground, the center pixel is
  within the 90m x 90m Land Cover Sample.

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LANDSAT IMAGE
Using the Land Cover data entry pages, you can
request your GLOBE Study Site image once you have
reported 250 measurements and submitted the GPS
coordinates of your school location.
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MAPPING

• Manual (Basic)
• Computer-aided
• satellite image (digital)
• MultiSpec software
• reference data, maps, aerial photos, etc.

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MAP USES

• studying the habitat of a certain animal or plant
• looking at the succession of fields to forests
• studying the rate of growth of a particular
  village, town or city
• looking at the amount of undeveloped land
• deciding how to protect water resources
• deciding where to plant certain crops during the
  next growing season.
• deciding new school boundaries
• choosing where to connect recreational trails to
  create one continuous system
• deciding how to efficiently run public
  transportation
• studying another specific question

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MAPPING
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MAPPING
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MAPPING
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MULTISPEC

• Free software for both Macintosh and PC
  computers.
• Allows digital manipulation of LandSat images
• zoom in/out
• examine different band combinations
• examine spectral properties of pixels/groups of
  pixels
• perform blue band correction of images
• Used to perform unsupervised clustering to create
  a computer-aided land cover type map

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COMPUTER-AIDED MAPPING
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COMPUTER-AIDED MAPPING
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ACCURACY ASSESSMENT
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ACCURACY ASSESSMENT
After we collect many Land Cover Sample Sites
throughout the GLOBE Study Site, perform an
accuracy assessment on the land cover type map.
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ACCURACY ASSESSMENT
Using the Land Cover Sample Site data, complete
the Accuracy Assessment Work Sheet.
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ACCURACY ASSESSMENT
Build an empty difference/error matrix.
Label the matrix with the titles and MUC classes.
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ACCURACY ASSESSMENT
Tally each row of data.
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ACCURACY ASSESSMENT
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ACCURACY ASSESSMENT

• Calculate
• Row Totals
• Column Totals
• Total Data Samples

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ACCURACY ASSESSMENT
Overall Accuracy indicates how well the map
identifies all land cover types on the ground.
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ACCURACY ASSESSMENT
Producers Accuracy indicates what percentage of
the time a particular land cover type on the
ground was identified as that land cover type on
the map. It expresses how well the map producer
identified a land cover type on the map from the
satellite imagery data.
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ACCURACY ASSESSMENT
Users Accuracy indicates what percentage of the
time a particular land cover type on the map is
really that land cover type on the ground. It
expresses how well a person using the map will
find that land cover type on the ground.
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ACCURACY ASSESSMENT
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ACCURACY ASSESSMENT
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ACCURACY ASSESSMENT
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CHANGE OVER TIME

• Comparing two images several years apart
• two images , several years apart (digital)
• these must be registered (images overlap exactly)
  to one another
• if you do not have the capability (software) to
  do this, contact the Land Cover Team to find out
  how you can have this done for you
• at least one completed land cover type map with
  accuracy assessment
• MultiSpec
• reference data, maps, aerial photos, etc.

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CHANGE OVER TIME

• Green may indicate an increase in urban type land
  covers
• Magenta may indicate a decrease in urban type
  land covers