Todd Mitchell

GEOG-499c

Lab 4: Raster Modeling

Question / Answer

 

Hand-In 1 (elevation graph):

 

Hand-In 2 (hillshade):

 

Hand-In 3 (elevation reclass with hillshade):

 

Hand-In 4 (distance to schools grid):

 

Hand-In 5 (allocation to schools grid):

 

Hand-In 6 (raster calculation):

 

Hand-In 7 (relational operation):

 

Hand-In 8 (raster addition):

 

Hand-In 9 (neighborhood statistics, range):

 

Hand-In 10 (neighborhood statistics, majority):

 

Hand-In 11 (zonal statistics, mean vs. variety):

 

Hand-In 12 (zonal statistics, graphs):

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Hand-In 13 (boolean operations):

 

Hand-In 14 (mosaic):

 

Hand-In 15 (resample, size 200):

 

Hand-In 16 (resample, size 400):

 

Resample Supplement (200 resample vs. 400 resample, graph):

 

Hand-In 17 (conversions):

 

 

Answer the following questions

 

1. While do we need reclassification sometimes? Give an example where it is useful?

 

Reclassification is needed to group objects based on certain conditions, or to assign new class values to the original class. Topographic or bathymetric values can be reclassified to show only a certain range of elevation or depth to isolate an area of study.

 

 

2. In conducting neighborhood statistics, what are the statistics types that you can use? What types of neighborhoods are available in ArcGIS? Can you give two examples where such statistics and neighborhoods can be used?

 

Neighborhood statistics available are minimum, maximum, range, sum, mean, standard deviation, variety, majority, minority and median. Neighborhoods can be annulus, circle, rectangle or wedge. Examples might be a dot map showing maximum harvested crop areas, or the average household income in a census tract.

 

 

3. In conducting Zonal statistics, what are the major statistic types are available? Give two examples whether they could be useful?

 

The zonal statistic types are minimum, maximum, range, sum, standard deviation, variety, majority, minority and median Areas in need of irrigation could be determined from zones of minimum rainfall and temperature value. Also, preferable skiing locations could be mapped based on zones of maximum snowfall and elevation value.

 

 

4. Why do we need to do resampling sometimes?

 

Resampling is necessary when overlaying rasters of different coordinate systems or different cell sizes. This way the raster layers are compatible, thus avoiding ambiguous overlay.