Flashcards in Scale Deck (13):
What is scale?
Relationship between the length of a feature on a map versus the length of that feature on the ground.
Scale does not tell us_______.
Scale does not tell us what the features on the map actually are:
That is the job of the symbols.
Scale certainly does come into play in helping you decipher what items might be, but only as an ancillary clue
How do we describe scale?
Scale statements all compare Map Units to Earth Units. We describe scale as 1 map unit to “N” earth units in a variety of ways from fractions to drawings.
formula is 1:n. 1 and "n" are always in the same unit like any fraction.
What are graphic scales?
They draw the map unit on the map and do not state it.
1 mile =
1 foot =
1 meter =
1 mile =
1 km. =
What are large scale maps?
Maps that show features that are relatively closer to the actual size of the features on the earth are called “large scale” maps.
Typically these maps:
-Cover small areas of Earth
Show a larger amount of local detail
-Comes from the RF scale fraction basically as 1/24000 is larger than 1/100000
What are small scale maps?
Maps that show features that are relatively farther from the actual size of the features on the earth are called “small scale” maps.
Cover larger areas of Earth
Show lesser amounts of local detail
What is mapping's catch-22?
Based on the scale of the map, you can estimate________.
You can estimate the potential accuracy of a mapped point on the ground and determine if that is good enough for your work
The National Map Accuracy Standard (NMAS) states that:_________.
For maps on publication scales larger than 1:20,000, not more than 10 percent of the points tested shall be in error by more than 1/30 inch, measured on the publication scale; for maps on publication scales of 1:20,000 or smaller, 1/50 inch.
What would a map at a scale of 1:48000 NMAS values be?
48000 * 1/50” = 960”
960”/12” = 80 feet
Is larger scale always better
Larger does generally mean more detail is visible, but larger also means that more data are available and thus size may be an issue. The catch-22. Why do we care? Below are two maps of the same area from different sources at their relative proportions.