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Who can use WAGDA data?

We provide data in two tiers: available to the public, and restricted by license agreement to UW students, faculty and staff to be used for non-commercial, educational purposes. If you are interested in acquiring some of the data that is restricted, email uwlib-gisatlib@uw.edu, and we'll put you in contact with the data vendor.

Where can I learn to use ESRI's ArcGIS software?

Several resources are available, a few of which are restricted to UW students, faculty, and staff.

  1. Getting to know ArcGIS Desktop, 2nd edition
  2. Book and data CD available for 3 day checkout from the Map Collection, Suzzallo Library, basement.  If you purchase this book it is accompanied by a demonstration copy of the ArcGIS software with a 180-day license. An online tutorial based on this text but designed to allow the user to bring in their own datasets is provided by the University of Arkansas Libraries.

  3. ESRI Virtual Campus Students, staff, and faculty at the UW may sign up for online, self-paced, no-cost training workshops provided by ESRI.

  4. ArcExplorer is a free, simple to use GIS data viewer available for download at http://www.esri.com/software/arcexplorer/index.html
    Although this has only limited functionality when compared with ArcGIS, it may be suitable for some projects or may provide some ideas about what GIS can do.
  5. Mapping Our World: GIS Lessons for Educators, ArcGIS Edition
  6. This book from ESRI Press is designed specifically for teachers to use in their classrooms, but may also be useful for others seeking to learn GIS software.  The full text of the book is available online in pdf format but when purchased the book is accompanied by an exercise data CD as well as a demonstration edition of the ArcGIS software with a one-year license.  In particular, see Module One: ArcMap Basics.

How can I subscribe to the campus GIS mailing list?

UW-GIS-L is an open, unmoderated e-mail list for discussion of issues relating to Geographic Information Systems. Any issues related to GIS can be discussed, such as "How do I ...;" "Where can I find ...;" "What do I need to do ...;" "I would like to share ...." Topics may include discussion of hardware, software, data, etc. To subscribe to the campus GIS mailing list follow the instructions on this page http://mailman.u.washington.edu/mailman/listinfo/uw-gis-l.  For general information about mailing lists at the University of Washington visit the Mailman List website at: http://www.washington.edu/computing/mailman/.

What types of files are provided on WAGDA?

Files hosted on WAGDA vary in the format and software used to access them.  The following is a list of some of the more common file types used on WAGDA.

  • Geographic data formats
    Geodata is information about geographic locations that is stored in a format that can be used with a geographic information system (GIS). Additional documentation about geodata can be found in the ESRI ArcGIS Help under the topic: What is a geodata?

  • Compressed files
    Compressed files packed multiple files into a single package. Many files on WAGDA are stored in a compressed format. You will need a copy of a decompression software such as 7-Zip for Windows installed on your machine to decompress files. The program is available as open source software and can be downloaded from: http://www.7-zip.org/ if you do not have similair software already installed.
  • ArcView Shapefiles 
    A Shapefile is an ArcView file format that can be used to create new themes from existing data. A shapefile has several component files, most commonly: *.shp, *.shx, and *.dbf. These files must be kept together to use the shapefile as a theme. Additional documentation about shapefiles can be found in the ESRI ArcGIS Help under the topic: What is a shapefile?
  • ArcGIS Geodatabases 
    Geodatabases come in different versions: Personal Geodatabase, File Geodatabase and multiuser relational DBMS. Additional documentation about the different Geodatabase formats can be found in the ESRI ArcGIS Help under the topic: What is a geodatabase?
  • Raster Datasets 
    Raster data is a large matrix of cells (or pixels) organized into rows and columns. Commone examples of raster data are aerial photos, elevation grids, or USGS topographic maps. Additional documentation about the different Geodatabase formats can be found in the ESRI ArcGIS Help under the topic: What is raster data?
  • ArcInfo interchange file (E00)
    The Arc/Info coverages are comprised of many individual files into a "folder" structure. These can be exported into a more portable format. Large coverages will be converted to multiple volumes (i.e. *.e00, *.e01, ...*.e99). Additional documentation about interchange files can be found in the ESRI ArcGIS Help under the topic: Importing an ArcInfo interchange file (E00)

  • Arc/INFO Coverages
    The Arc/INFO data model stores individual thematic map layers as coverages. A coverage is a directory consisting of several files.

What do different file extensions mean?

When I unzip my file, I get a whole bunch of files: parcel.shp, parcel.shx, parcel.dbf, etc. There are many files with the same name, but different extensions -- what are these files for?

A theme in ArcMap is comprised of many separate files that work together. ArcMap needs all of these files to be able to add the theme into your project. Don’t delete anything! The three files you’ll always see are *.shp, *.shx, *.dbf.

ESRI lists examples of other ArcMap file extensions

What kind of DOQs/DOQQs do you have, and how do I view them?

DOQ/DOQQs are a digital form of aerial photography. Check out our collection of digital aerial photography.

Why don't my datasets line up?

The most common reason that datasets that do not overlay each other is that the files miss projection files or have incorrect projection files. Please read the document How to align layers in ArcMap to help you resolve the problem.

For a stronger understanding of the critical geospatial data concepts of projections, coordinate systems, and datums, work through this exercise created by Phil Hurvitz.

How do the geospatial data concepts of Projection, Coordinate System, and Datum work together?

Being comfortable with and working effectively with these concepts is essential to avoid bogus analyses, incorrect data summaries, corrupted data, and confusion. Phil Hurvitz has created this Projection/Coordinate System/Datum Exercise to test or build your knowledge of these concepts.

How can I extract one shape from a set of larger shapes?

If you want to select a small area from a dataset with a larger geographic extent, e.g. a few blocks within Seattle, a single county from the entire state of Washington, you can clip that area and any associated data layers much as you would use a cookie-cutter. Another option would be to go to the Selection menu and Select by Location, where you can select all features that have their center in, or are contained by, the features in the larger layer: i.e. all the census tracts within a particular county in Washington. Once you have made the selection, you can left-click on the layer that contains your features in the Table of Contents, and go to Data and Export, to export the selected features out as a new data set.

Where can I find census data and layers, and how do I get them into GIS?

To get census data into GIS, you need to obtain two pieces of information: the actual data, and the boundary files that you will join the data to in order to map it. There are many options for getting the data, which include: using the geodatabases WAGDA has created for Puget Sound and Washington, downloading data and boundaries from the Census Bureau's American Factfinder, downloading data and boundaries from ESRI's Census Watch, using the Geolytics data CDs in the UW library, or downloading historical census data and boundaries from the National Historical Geographic Information System. Each source has it's advantages and disadvantages in terms of ease of access, ease of use, use restrictions, available time series, and available level of geography. See the Census Source Table (pdf format)for a comparison of the different sources, the WAGDA Census page for links to access these resources, and the WAGDA Census Help page for guidance in using them.

How do I map (geocode) addresses?

In order to match addresses to a street network, you must set up an address locator service using the ArcCatalog prior to selecting the geocode option in ArcMap. The Address Locator is essentially a set of instructions that tells the GIS how the attribute table of a particular street network is constructed, so it can appropriately match addresses to that network. In order to set up the locator service, you will need to know how the street network table is constructed - does it contain just the street address, or are there zip codes (also called zones) as well? Does it differentiate between addresses on the left and right side of the street? Is the network in a shapefile or geodatabase format? Examining the file and viewing the associated metadata will help you answer these questions and set up the service. For more information, see the following resources:

How do I backup my GIS project?

There are a range of options for backing files associated with a GIS or other school projects when using computers within the Suzzallo GIS lab. Below are some of the different options:

  1. Use the shortcut on the desktop to access the U Drive which has 5GB of storage space provided by the UW-IT.
  2. Use a USB/thumb/jump drive which can be purchased at various locations across campus.
  3. Use a portable USB hard drive.
  4. Burn files to a CD or DVD using the burning software on the lab computers.

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Where can I get/use GIS software?

The UW has a site license with ESRI, the producer of ArcGIS and many other products. The site license requires that software be installed on University-owned computers AND be used only for educational purposes or non-profit reseach. This site provides information about how to get the software, how to install it, and how to connect with the GIS users at the UW.

Alternatives for current UW Students:

  1. ESRI offers a free, one-year license to students enrolled in GIS courses at the UW. Software must be requested by the faculty member of the course and can be installed on student-owned computers.
  2. Computer Labs at UW
  3. Students may purchase ArcView and many of its extensions at an educational discount price (without the one-year time-out license) by calling ESRI TeleBusiness at 1-800-447-9778.
  4. For basic GIS work you can download ESRI's free GIS viewer, ArcExplorer.

Can you help me figure out what data I need for my project?

If you're just starting out with a GIS project use the Digital Geographic Data Needs Assessment to help you clarify your data needs. Staff in the Map Collection, Suzzallo Library can assist you with collecting and formating data for project use. Or email us at uwlib-gisatlib@uw.edu

Why do I get the ! next to my data layer?

When a data layer is added to ArcMap, the pathway where that data is stored is stored in the .mxd file. If you move the data layer to another folder, or move the .mxd file to another computer, the pathway to find and display the data will no longer be valid. To repair this:

  1. To resolve the broken link in a batch method, double click directly on the red exclimation mark next to the top most layer in the table of contents and use the add data dialog that appears to find the corresponding dataset.  ArcGIS Desktop will search for other datasets in the table of contents that might be located in the same directory.  Repeat this process selecting the top broken link till all links are repaired.
  2. To repair one layer at a time:
    1. Right-click the layer you want to fix and click Properties.
    2. Click the Source tab.
      When a layer can't find its data source, you'll see information about the data it's looking for but no extent or coordinate system information.
    3. Click Set Data Source.
    4. Navigate to and click the layer's data source in the Browse dialog box, then click Add.
      The Source tab now shows the path to the data source, as well as its extent and the properties of its coordinate system.
    5. Click OK.

To avoid this problem with map documents, see: How do I set relative paths in ArcMap? 

What is an .e00 file?

ArcInfo interchange file (E00)

The Arc/Info coverages are comprised of many individual files into a "folder" structure. These can be exported into a more portable format. Large coverages will be converted to multiple volumes (i.e. *.e00, *.e01, ...*.e99). Additional documentation about interchange files can be found in the ESRI ArcGIS Help under the topic: Importing an ArcInfo interchange file (E00)

What do I do with a file that has a .zip/.tgz/.gz extension?

Compressed files packed multiple files into a single package. Many files on WAGDA are stored in a compressed format. You will need a copy of a decompression software such as 7-Zip for Windows installed on your machine to decompress files. The program is available as open source software and can be downloaded from: http://www.7-zip.org/ if you do not have similair software already installed.

What does an Arc/Info coverage look like?

When I unzip my file, I get two folders labeled "parcel" and "info." What is this?

This is an Arc/Info coverage, which can be read by ArcExplorer, Arc/Info, ArcMap or ArcView. When a coverage is copied to your computer, two folders are created – one labeled with the name of the coverage, one labeled "info." If you add more Arc/Info coverages to the same directory on your computer, additional folders are created for each coverage, and additional information is stored in the one Info folder. The Info folder holds database information about the coverage, which is pointed to by files in the coverage folder. You cannot successfully move or delete Arc/Info coverages using ArcView because of this relationship – these kinds of operations must be completed from within Arc/Info. However, you can successfully view Arc/Info coverages in ArcView and ArcMap.

To open an Arc/Info coverage in ArcView:

  1. Select "Add Theme."
  2. Navigate to the directory containing the coverage you’d like to use.
  3. Click once on the coverage folder; you’ll see a list of files contained within the coverage. Most frequently seen are polygon, arc, node, and annotation. Most often you’ll want to use polygon or arc; sometimes you’ll want annotation, which is an Arc/Info text layer associated with the polygons or arcs.
  4. To add a layer from within this coverage, click on the layer you’d like to add (to add more than one layer at the same time, hold down the shift key and click on each layer to add).
  5. Click "OK" – your themes are now added to your View

Where can I find out about projections?

First of all, make sure you read and keep copies of metadata for each datafile you'll be using, to keep track of information such as projection, publication date, source, etc. Another resource that may help you determine the projection of your data is the Projection_checker. The Projection checker is a set of Washington State themes (boundary, hydro, and transportation) from USGS which are in geographic, State Plane (N & S, in feet), and UTM (Zone 10 in meters); NAD27 and NAD83. These set of data will allow you to quickly display basic themes to see if they spatially "match" the data for which you don't know the projection.

To troubleshoot a projection problem in ArcGIS, these practical resources may help.

To learn how to reproject your data, consult the Projections Toolset in the ArcGIS Desktop Help. If you'd like more detailed information on projections and selecting the appropriate type, talk to your instructor. If you're interested in learning more about different projections, check out Peter Dana's Guide to Map Projections.

For a stronger understanding of the critical geospatial data concepts of projections, coordinate systems, and datums, work through this exercise created by Phil Hurvitz.

There are also several useful books about map projections such as Map projections--a working manual (1987) published by the USGS; Understanding map projections (2000) from the ESRI Press; and Map projection transformation : principles and applications (2000). Search the subject term "Map Projection" in the UW Libraries Catalog for additional titles.

What style/format should I use to cite digital cartographic data?

A good reference for citing digital cartographic data is the book, Cartographic Citations: A Style Guide by Suzanne M. Clark, Mary Lynette Larsgaard, and Cynthia M. Teague (American Library Association, 1992). An online source is Citing Geospatial Data Resources provided by the University of Waterloo Library. The UW Libraries provides links to additional citation guides for maps & cartographic materials. If you have any further questions on this subject please contact the Map Collection at uwlib-gisatlib@uw.edu.

Color Oversize Printing - What are the Options?

On the UW-Seattle campus there are several options for oversize color printing

Students may find the 36" wide plotter printers available in the computer labs in Mary Gates Hall and Odegaard Undergraduate Library to be most convenient. Users are strongly encouraged to talk with a lab staff person before printing. Printing large format color plots is not cheap! You'll want to make sure you've got everything setup correctly in your layout before making the plunge.

Another option is provided by UWPosters.com located in Health Sciences T-271. Submit orders online or in-person with payment options UW Budget, credit card (Visa, Mastercard), or personal check.

How do I get data tables into Excel, and how can I map them?

See the Import Tables into Excel page for instructions on importing text files and pdf tables into Excel. Beginning with ArcGIS 9.2, Excel spreadsheets can be directly added to ArcMap. For previous versions of ArcGIS, Excel spreadsheets must be saved in dbf format in order to be added to ArcMap. Data in the Excel or dbf file can be joined to a boundary file based on a common field, which allows the data to be mapped. For an example on how to join tables, see the tutorial for using the WAGDA Census geodatabases, which includes this step in figures 6 and 7. Using Excel spreadsheets (or the dbf format) for adding data to maps is best for small, isolated projects. If you are working with large datasets or are working on an extensive, long-term project, storing your data in a database like Access may be a better choice.

How do I set relative paths in ArcMap?

How and why setting relative paths within Arcmap is covered in the ArcGIS Desktop help materials here:  Paths explained: Absolute, relative, UNC, and URL