Select By Location v. Topological Operators


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Lab test 2 is this Wednesday and Thursday.  You will have the first 30 minutes in lab to answer 2 questions.  The questions are:

  1. Determine the area in hectares of forested sites (deciduous, evergreen, and mixed) older than 20 years old that are within 50 meters of a stream.
  2. Determine the area in hectares of forested sites (deciduous, evergreen, and mixed) less than 20 years old, grassland/herbaceous, barren land, and shrub/scrub that are outside a 1 mile buffer of all developed areas (Developed Open Space, Developed Open Space – high, Developed Open spAce – Low, developed open space – med).

ATTRIBUTE QUERIES: AND, OR

GIS Data Layer:

  • LayerName: PlayingCards
  • Description: There are 52 polygons; each polygon has one record in the attribute table
  • Fields in the attribute table:
    • SUITE: club, spade, heart, diamond
    • COLOR: red, black
    • FACECARD: yes, no
    • VALUE: 1 – 13 (ace = 1, J = 11, Q = 12, K = 13)

Pictures of the 52 playing cards

SAMPLE QUERIES:

‘SUITE’ = “heart”

‘VALUE’ < 6

‘VALUE’ < 5 AND ‘SUITE’ = “club”

(‘VALUE’ < 5 AND ‘SUITE’ = “club”) OR ‘FACECARD’ = “yes”


SELECT BY LOCATION

The Select by Location command selects WHOLE polygons.

A screenshot of a social media post Description generated with very high confidence

Does the above procedure answer the “How many acres of each type are in our analysis extent?” question? NO!!!

  • Notice that there are areas of selected polygons that fall outside the analysis extent feature.

The above procedure answers the “How many acres of each polygon have at least a part that falls within our analysis extent?” question.


COMPARE THE SELECT BY LOCATION FROM ABOVE WITH THE CLIP PROCESS BELOW