Lab - Remote Sensing

Ge151: Spring 2011

Mojave National Preserve: Remote Sensing & GIS

Geographical Information Systems

Introduction to ArcMap

In this lab you will be given a demonstration of the capabilities of a GIS system called ArcView. Like most packages, this software is best learned by hands-on usage.The ArcGIS tutorial will consist of the following:

An overview of ArcGIS (ArcMap, ArcCatalog, and ArcToolbox). We will cover the data types used in the project and how to navigate ArcMap. (DEM's, ASTER, SPOT, LandSat, Roads, Cities, Geologic Units)
How to combine multi-band data into images
How to utilize several layered datasets
How to create a publishable map, with scale bars, legends, etc..
Printing your final maps.

After the presentation, you will break up into small groups. Each group will be assigned one of the areas that we will visit during the field trip. Your goal is to study the remote-sensing data available in the Arc project, interpret the geologic units that you expect to see in the field, and create a map or two illustrating these interpretations. You should attempt to bring to bear as many different data types as possible, and combine to provide as complete a picture as you can. The datasets we will be using are:

Digital Orthophoto Quarter Quadrangle (DOQQ) - Grayscale digital aerial photography, with a resolution of 1 meter
USGS Topo Maps - Contour maps with 10 meter vertical resolution
SPOT (Satellite Pour l'Observation de la Terre) - Grayscale Satellite images in the visible band, with a resolution of 10 meters.
ASTER (Advanced Spaceborne Thermal Emission and Reflectance Radiometer) - Visible-Near Infrared data with 15 meter resolution. Three bands: 1 - 520-600 nm (green), 2 - 630-690 nm (red), 3 - 760-860 nm (Near IR).
Landsat Thematic Mapper - Visible through Thermal Infrared data with 7 separate bands at 28.5 m resolution. 1 - 450-520 nm (blue), 2 - 520-600 nm (green), 3 - 630-690 nm (red), 4 - 760-900 nm (Near IR), 5 - 1550-1750 nm (Near IR), 6 - 10,400-12,500 nm (Thermal IR), 7 - 2080-2350 nm (Near IR)
NED (National Elevation Dataset) - Topograhpy data compiled and digitized by the USGS from existing datasets. ~30 meter/pixel horizontal resolution.
SRTM (Shuttle Radar Topography Mission) - Radar topographic data obtained from the Space Shuttle. ~30 meter/pixel horizontal resolution.
AIRSAR (Airborne Synthetic Aperture Radar) - Radar backscatter data obtained from airborne missions. C-Band data (5.7 cm) is used here.

The four areas we will be looking at are:

Pisgah Volcanic Field (116.38E, 34.75N)
Kelso Dunes (115.73E, 34.92N)
Cima Dome and Volcanics (115.70E, 35.29N)
Soda Lake (116.09E, 35.15N)

You should come up with a short description of what you see in the data, and be prepared to present it to the group when we arrive at the site. What are the characteristics of your region in the visible band? in the infrared? what are the morphological distinctions of the units on various scales? Examples of specific questions you might consider based on various data are:

Kelso Dunes:

Landsat: Experiment with different Landsat band combinations - try to determine which dunes are active, and which are inactive. Hint: Use alfalfa fields (116.78E, 34.89N) to determine which bands highlight vegetation.)
ASTER: Try to determine the source of sediment for the dunes, based on the ASTER signature of the areas surrounding the dunes.
SRTM/NED: Use the profile tool to look at the topograhpy of the dunes. How high are the largest dunes? What are the angles on the steepest parts of the large dunes. How does this compare with smaller dunes nearby? Can you tell which way the dunes are moving?

Cima Dome and Volcanics:

Geologic Map: Look at the geologic map for this area under the shapefiles layer. What are the ages of the various volcanic features in this area?
Landsat: Look at the signatures of the Cima lava flows and cinder cones in various bands. What are the effects of aeolian mantles? What is the source of brightness in Band 6? Arvidson et al. (1993) described a correlation between band 5 brightness and age. Based on this, which lava flows are older? Why is this?
SRTM/NED: What differences in topography are evident on lava flows of different ages? What is the average thickness of these flows?
AIRSAR: What differences are evident in the radar brightness of different parts of the volcanic field? Speculate how these differences may correlate to particular variables, such as age. [Farr, 1992] discusses this data at Cima.

Soda Lake:

Landsat: Look at the brightness in different bands of Soda lake bed evaporites. Compare with published lab spectra (from Crowley, 1991) to explain signatures, and identify possible mineralalogies.
Topo Maps: What is the main source of water for Soda Lake? What happens as Soda Lake is gradually flooded? (i.e., what is the outlet of the lake?)
SRTM/NED: How deep can Soda Lake get, before it spills over? Is there any evidence of previous shorelines in the topography? What sort of slopes are present on this playa?

Pisgah Volcanic Field:

SRTM/NED: Is there an identifiable volcanic source in the topographic data which stands out? How thick are the lava flows here, and can you estimate a reasonable volume from the approximate aerial extent of the unit?
Geologic Map: Does the geologic map confirm the potential sources identified from topo data? What is the age of this unit?
AIRSAR: What variations in radar backscatter are apparent on the flows, and what might this signature correspond to on the ground?
ASTER/LANDSAT: For the most part, Pisgah is black in all bands. However, are there any subtle differences that can be identified by stretching the data? Do these differences correspond to any other datasets, and if so, what might be going on? Using the combined datasets, can you speculate on/map different eruptive phases, and guess in which order they were formed? Check out [Gaddis, 1992] for some clues.

NOTE - You will be discussing the results of this lab when we arrive at your site on the field trip. Therefore remember to bring your final maps. Be sure they are understandable to others - i.e., include North arrows, scale bars, Landsat bands used, etc. There are good papers on remote sensing of each of the subject areas, which you may wish to browse before the trip.

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