Introduction: This week we will examine local landforms and surficial geology using the GIS (Geographic Information System) software package ArcMap. Our goal is to learn some of the basic operations of the software, how to download and manipulate various file formats, and develop a basic understanding of the relationship between topography, surficial materials and landslide hazards in the Tully Valley, an area approximately 50 miles west of Hamilton.

ArcView: It will be necessary for you to download and print the document file "Intro to ArcView", which is available as Fileshr01/labsandclasses/geology210/labspring 2001/lab3. Please save your printed version for future reference. Note that ArcView is loaded on the Windows machines in Lathrop 305 and Lathrop 401. You must have a Zip disc for storing your ArcView project files, and be sure to bring that disc with you for this and all subsequent labs. We will discuss the vagaries of file structures and file labels in ArcView. Please be sure to save your work often, since ArcView can be somewhat unstable.

(Free) GIS Data Sources for Central New York:

1. CUERD (Colgate University Environmental Resources Database): This site (http://cuerd.colgate.edu/) is a useful repository of local data. Take time to explore the site and become familiar with the types of information available, and the extent of coverage. The data at this site are downloaded as Zipped files. Whenever you download data from this or any other site, download to your own Zip disc.

2. Cornell University Geospatial Data Repository: This site (http://cugir.mannlib.cornell.edu/index.html) has statewide coverages for a number of data types, including topography, political boundaries, hydrology. A number of coverage scales are available.

3. New York State GIS Clearinghouse: Visit this site (http://www.nysgis.state.ny.us/) for a variety of coverages, including complete statewide coverage raster graphics files of topographic maps and digital orthophotographic images of most of the state.

4. New York State Geological Survey: Statewide surficial geology and bedrock geology ArcView converages can be downloaded from this site. (http://www.nysm.nysed.gov/gis.html)

Tully Valley Landslides: A significant landslide occurred in the Tully Valley area The USGS has a number of online documents that address the causes and effects of the Tully Valley landslides hazard zone. Three .html files (Landslide Hazards in Glacial Lake Clays…, Tully Valley Landslide Study, Tully Valley Landslides) are included in the Lab #3 folder in Filesh01/labsandclasses/geology210/. Please take a look at these documents before you come to lab. The maps and cross-sections in these documents help explain the origin of the 1993 landslide, and provide an overview of the geological history of the Valley and its surficial geology.

Maps and ArcMap coverages: To begin this project you will need the following files available on your Zip disc. I encourage you to make a single new folder on the disc that will hold all the files used for this lab.

1. Otisco Valley and South Onondaga 7.5 Minute Quadrangle DRG: These files are in the Lab 3 folder at the class server address. Note that they are zipped files, which you should copy directly to your disc and then extract. DRG (Digitally Rastered Graphic) files are .TIF format but are georeferenced (GeoTif) in UTM and lat/long coordinate systems. This means that you can examine the topographic map image and determine map coordinates. When you have unzipped these files, you may wish to examine them using DLGV viewer which we used in last week’s lab. DRGs can be opened in Surfer also, but the files are sufficiently large that it is a slow process. DRGs can be added as a theme in ArcView (Image Data Source) and viewed, as well (see below).

2. Surficial Geology ArcView Shape File of the Finger Lakes Region: This file can be downloaded from the CUERD site or the New York State Geological Survey site (#1 and #4 above). Note again that this is a zipped file which you download to your Zip disc and then extract all the enclosed files to the appropriate folder on your disc. You will also want to have the text file which explains the map units.

3. DEMs and Digital Orthophotos: While not required for this lab exercise, the DEMs of the South Onondaga and Otisco Valley 7.5’ quads are also available in the Lab 3 folder. The DEMs can be opened directly in DLGV or Surfer; the Digital Orthophoto files are in Geotif format, and can be opened in ArcView. Note that the Orthophoto files are quite large (25 meg or so), and thus can fill up a single Zip disc rather quickly.

Making an Overlay Map: The goal of this exercise is to produce a 5 x 5 km map of the landslide area near Bare Mountain showing the topography and surficial geology.

Producing a simple map using ArcView: Open ArcView on any of the Windows machines in Lathrop 305 or 401. Make sure you have your Zip disc with the files noted above inserted in the drive. When ArcView is fully up, you will be prompted to proceed with a new project and new view. Click yes, and continue. You will Add Themes to the View – I suggest adding the DRG topographic map files first, then adding the surficial geology coverage next. You will then need to manipulate the legend attributes to produce transparent overlays of the surface geology and add labels. We will review these steps thoroughly in lab.

When you have a view that displays the coverage you want, select Layout to produce a map. The layout will also need editing to produce appropriate output. You can print the layout directly to a printer (note that the color printers in 401 are not yet networked, but a black-and-white output is fine for this exercise. The layout can also be exported as a bitmap file for printing using other software.

1. What is the origin of the surficial deposits are mapped in the slide area?

2. What kinds of map information would be useful to predict future landslide hazards zones in the Tully Valley area?