Exercises--all due September 18 at the beginning of class
I. Digital topography of the US. This exercise gives you a chance to investigate the broad topography of the US. Main tasks:
Read this pamphlet: Landforms of the conterminous US--a digital shaded-relief portrayal (Note that it may not launch right in Adobe Acrobat if you just click on it. Right click it and save ("target as") to your local machine). I have also provided it to you as a hard copy. Note that I have cut out pages 5 and 6 and part of page 4 because I expect you to generate a map of physiographic provinces yourself (see below). When I return the graded assignments, I will give you that figure so you can compare your scheme with that presented in the discussion. Note that you should use the interactive shaded relief that is available from the USGS seamless site ("View and download US data") as a simple way to view the US shaded relief rather than the low quality images in the pamphlet. Here some other views of the physiography of the United States (Images
below are from Professor Locke at Montana):
Review the maps above, from Seamless and in the text (not annotated) and read the pamphlet (Landforms of the conterminous US--a digital shaded-relief portrayal) that accompanies the digital map and write a one page (maximum), typed discussion of how digital shaded relief maps are made, what Digital Elevation Models are, and what the advantages of this technique are. Note that on pages 10 and 11 the map is annotated to point out numerous landforms. Some are obvious and others are not. Familiarize yourself with all of them.
Answer these questions (also typed on a separate sheet). Read chapter 2 of Ritter, et al. to accompany your answers.
Which landform is the most interesting to you (annotated ones on the maps of Figure 4)?
Select four of these landforms and describe the dimensions, form, and development of each in just a few sentences. Only use what you can see in the shaded relief.
Which parts of the US do you think are dominated by orogenic versus epierogenic (defined in textbook) processes?
Where and when has climate dominated the landscape?
As you look at the landscape of the US, identify and delineate at least 10 physiographic provinces. Provide a brief definition of the characteristics of the landforms that correspond to each province.
Example: The Basin and Range is a physiographic province in the western US that extends form Southern Idaho south to southeastern California and from eastern California to central Utah. It appears again in southern Arizona and central New Mexico. It is delineated by a region of subparallel 50-100 km-long ranges trending generally north-south. The morphology of the ranges is "sharp," while the basins are flat and smooth.
Here is the definition of physiographic province from The Glossary of Geology:
"A region all parts of which are similar in geologic structure and climate and which has consequently had a unified geomorphic history; a region whose pattern of relief features or landforms differs significantly from that of adjacent regions. Examples: the Valley and Ridge, the Blue Ridge, and Piedmont provinces in the eastern US, and Basin and Range, Rock Mountains, and the Great Plains Provinces in western US."
II. For any place in the US with Seamless coverage, choose a landscape or landform of interest (possibly the one above in part 3--but be careful not to choose too large of an area, or ArcGIS and Seamless won't be happy) follow the demonstration from DEMs in ArcGIS--Lesson 1 and produce the following:
Nice map with color coded and semi-transparent elevation and hillshade below make sure to add explanation and scale bar. Print out to turn in. In addition, write a one paragraph description of the landscape depicted in your map and turn it in. Try to stick to basic description, don't do other research. Emphasize only what you can see in your map. An example might be (based on Shaded relief and DEM for the eastern South Mountains): This view of the eastern South Mountains near Phoenix Arizona shows a NE-trending mountain rising to about 780 m (about 450 m above the adjacent basin). The range is cut by valleys trending mostly parallel and some normal to the ridge axis. The transition between the mountain front and the basin is intricate and sinuous. A satellite range with an axis parallel to the main range is evident in the southwest. To the northeast, several small hills decorate the basin floor. The hills and the intricate range front are consistent with sedimentation and burial of the foot of this range and indicate its likely prior greater extent.
Map of difference between NED and SRTM DEMS. Add scale bar and print out to turn in.
Then write a one paragraph explanation of possible reasons for the differences between the two measures of the topography.
III. For any place in the world, choose a landform of interest in Seamless (different from the one above--but be careful not to choose too large of an area, or ArcGIS and Seamless won't be happy) follow the demonstration from DEMs and imagery in ArcScene--Lesson 2 and produce the following:
3D view of the topography with at least two different and interesting views of the feature printed out. (If you are not in the US, use the 1 arc second SRTM data from Seamless)
3D view of the area depicted in some imagery (see what is available under the orthoimagery download tab once you have found your target of interest from Seamless) with at least two different interesting views printed out.
Write a one paragraph description of the landscape depicted in your map and turn it in. Try to stick to basic description, don't do other research. Emphasize only what you can see in your 3D views (but include what you see in the imagery). Example (based on this image: ArcScene image of the South Mountains looking west--DOQQ over DEM): This view of the eastern South Mountains near Phoenix Arizona shows a NE-trending mountain rising to about 780 m (about 450 m above the adjacent basin). The small drainages trend opposite to the view. The range is irregular due to the incision of the drainages while the basin is rather flat in the foreground. Between the two, the piedmont steepens as it approaches the range, contacting it in a sharp and sinuous boundary between aggraded sediments and the bedrock of the range. The DOQQ imagery clearly shows the contrast between the finely textured urban area adjacent to the undeveloped (but trail covered--white sinuous lines) mountains. The boundary between the urban environment and the range is abrupt. The foreground shows larger patches of land associated with light industry.
