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