"Combine" : a Local Function Correct Answer ArcGIS
function that assigns a value to each unique combination of
input grid values
Can do as equation in the raster calculator
Uses multiple datasets
Major drawback:
Value is arbitrary and does not communicate meaning.
Active Correct Answer Sensor emits and receives own energy
reflected from target e.g. Lidar/Radar
Advantages and Disadvantages of Unsupervised Classification
Correct Answer + Advantages
•No prior knowledge (a priori) of the area of interest is required.
BUT... need knowledge of the area to interpret the resulting
classes!
•Opportunity for input error is minimized
•Unique classes recognized as distinct clusters of unique spectral
classes
- Disadvantages
•Classes statistically based...may not match field data well
•Spectral classes are not necessarily information classes
•You still have to interpret the classes and decide whether to
lump or split classes
, AVHRR Correct Answer Sea Surface Temperature
Binary Model Correct Answer 1) Define the objective and the
decision criteria
2) Identify the necessary data (raster format)
3) Reclassify each raster layer into binary values
1 = satisfies criteria
0 = does not satisfy criteria
4) Multiply reclassified binary layers together
Change Detection Correct Answer -LIDAR
Classification Correct Answer Unsupervised
Supervised
Combination Matrix Correct Answer A method to combine
numeric attributes so that their values are in a defined numeric
place within a larger number.
The resulting map contains both:
- vegetation codes (tens place)
- slope codes (ones place)
Convolution Correct Answer you Know This in GIS as
Neighborhood Analysis
Convolution involves the passing of a moving
window(Neighborhood) over an image