Geospatial Data Resources Guide: FAQ

1. Who can use WAGDA data?
2. Where can I get/use GIS software?
3. Where can I learn to use ESRI’s ArcGIS software?
4. Where can I learn to use other GIS software?
5. Can you help me figure out what data I need for my project?
6. Why do I get the ! next to my data layer?
7. What is an .e00 file?
8. What does an Arc/Info coverage look like?
9. When I unzip my file, I get two folders labeled "parcel" and "info." What is this?
10. What do I do with a file with a .zip/.tgz/.gz extension?
11. How can I subscribe to the campus GIS mailing list?
12. What types of files are provided on WAGDA?
13. What do different file extensions mean?
14. What kind of DOQs/DOQQs do you have, and how do I view them?
15. Why don't my datasets line up?
16. Where can I find out about projections?
17. How do the geospatial data concepts of Projection, Coordinate System, and Datum work together?
18. How can I extract one shape from a set of larger shapes?
19. What style/format should I use to cite digital cartographic data?
20. Where can I find census data and layers, and how do I get them into GIS?
21. Color Oversize Printing - what are the options?
22. How do I export GIS data to CAD? (PDF)
23. How do I map (geocode) addresses?
24. How do I get data tables into Excel, and how can I map the data?
25. How do I set relative paths in ArcMap?
26. How do I backup my GIS project?
27. What are Business Analyst and Network Analyst– how are they different?
28. Who do I contact for more information?

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 us, and we'll put you in contact with the data vendor.

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

1. ESRI Tutorial Videos on YouTube.
2. ESRI e-Learning Students, staff, and faculty at the UW may sign up for online, self-paced, no-cost training workshops provided by ESRI.
3. Getting to know ArcGIS Desktop, 5th edition.
4. Getting to Know ArcGIS Pro
5. Mapping Our World: GIS Lessons for Educators, ArcGIS Edition. 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 book is available online but when purchased is accompanied by an exercise data CD as well as a demonstration edition of the ArcGIS software with a one-year license. 
6. ESRI Community Forums, a place to explore problems and solutions from a worldwide community of ArcGIS users.
7. An instructional video for using ArcGIS StoryMaps produced by Ashlee (GIS Lab Graduate Student Assistant) is available here.

These resources are useful for members of the UW community and for those without a UW NetID or access to ESRI's GIS products.

1. QGIS Training Material, provided by the developers of QGIS, an open-source GIS software product.
2. Intro to GIS with QGIS, an 8-10 hour free, self-paced introductory course in GIS terminology, applications, and software use. HIGHLY RECOMMENDED for anyone who is new to GIS and looking to learn the basics outside of formal GIS courses. Created by Brown University Libraries.
3. Additional Mapping Tools and Software. Mostly online platforms and software that provide an alternative to ESRI's products. Each product has its own unique advantages and skills required to use it. For assistance with these products, visit the GIS lab during assistance hours, contact the GIS lab team, or explore online tutorials related to each product.

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 the UW-GIS-L info page.  For general information about mailing lists at the University of Washington visit the Mailman List website.

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 pack 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 similar software already installed.

• ArcGIS Pro/ArcMap Shapefiles 
  A shapefile is an ArcGIS Pro and ArcMap 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.

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? Do I need them all?

A shapefile in ArcGIS Pro (or theme in ArcMap) is comprised of many separate files that work together. All of the seperate files are needed to be able to add the data into your project. Don’t delete anything! The three files you’ll always see are *.shp, *.shx, *.dbf.

If you move any of the files in your file storage, make sure to move all of the separate files together.

Esri lists other file extensions for ArcMap and ArcGIS Pro.

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

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 HowToAlignLayers.doc document linked below 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.

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.

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.

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) 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.

See our geocoding page under the GIS Tutorials tab.

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 50 GB of storage space provided by the UW-IT.
2. Use Microsoft OneDrive connected to your UW Net ID, either through desktop app or OneDrive website.
3. Use a portable USB/thumb/jump drive which can be purchased at various locations across campus.
4. Use file storage on Canvas, which can be found in the "Account" navigation pane.

The UW has a site license with ESRI, the producer of ArcGIS and many other products. The site license requires that software be used only for educational purposes or non-profit research. 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.

Other ways to access ESRI software 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
   • GIS Lab, Suzzallo Library, ground floor. GIS Lab Assistant hours posted on lab webpage.
   • UW-Seattle General Access Labs providing ArcGIS software.
   • UW-Tacoma Campus Labs providing ArcGIS software
3. If your personal device has difficulties running ESRI software, Student Technology Loan Program is free for students and offers various loan periods on equipment that can successfully run ArcGIS software.

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 you can email us.

When a data layer is added to ArcGIS Pro, 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 in ArcMap, see: How do I set relative paths in ArcMap? 

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)

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 similar software already installed.

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

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. If you have the name or the EPSG code of your coordinate system or projection, epsg.io is an easy-to-use platform for finding out more information. To find the coordinate system of a map layer in ArcGIS Pro, right-click the layer in the "Contents" pane and select "Properties". In the pop-up box that opens, follow this path: "Source" --> "Spatial Reference" --> "WKID". If "Authority" is listed as "EPSG", "WKID" is the EPSG code.

To learn how to reproject your data, consult the Coordinate Systems section in the ArcGIS Pro 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.

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

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

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.

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.

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-gis@uw.edu.

On the UW-Seattle campus there are two primary options for oversize color printing:

1) UW Creative Communications offers large format poster printing. 

2) UWPosters located in Health Sciences T-271.

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

Business Analyst and Network Analyst are both extensions of ESRI's ArcGIS software that allow for analysis of spatial data. There is some overlap between Business Analyst and Network Analyst functions, but Business Analyst data can perform a wider breadth of functions. Business Analyst data includes business, consumer spending, and demographic information that provides network information while Network Analyst is limited to routing analysis.

For further information on Business Analyst, see the GIS Tutorials Business Analyst page.

If you have more questions about GIS, please feel free to contact us. Our email is <uwlib-gis@uw.edu>. For basic questions about what the library offers, call our help desk at 206-543-4164. Or come visit the Government Publications, Maps, Microforms, and Newspapers help desk or the GIS Lab for more information.