Environmental Science, Policy and Management

Finding existing GIS data is a common but often difficult task.  Sometimes the data you would like is simply not available, but other times it’s just difficult to find.  Here are some strategies for finding data.

Search Engines

Searching for data online is going to require a search engine.  Many search engines have advanced options that can help narrow down a search or restrict the results.  For example, Google has menus for Settings and Tools, as well as searches targeted to specific results like images.

Search Terms

Keep your search terms broad.  Also, try synonyms for terms you are interested in.  For example, if you were looking for a shapefile of beaches in California, you might search try separate searches for “beach shapefile” or “coast shapefile”.  Also, try synonyms for the data type. “GIS”, “map”, “geospatial”, and “shapefile” might find different but relevant results.

Think about how data might be developed or what kinds of layers would go into your analysis rather than terms that define your final product.  For example, you might be interested in identifying areas considered a “food desert” but you might need to look for layers for “census data” and “grocery store locations”.

Results

Search results for geospatial data often fall into one of three categories.

1. Good: blog posts explaining where to find data, why there is a lack of data, or what tools could be of use for your field.
2. Better: Question board responses on sites like Stack Exchange. These can be a treasure trove of solutions, but also frustrating if your question was posted a while ago and has no answers.
3. Best: Sites like repositories with links to download the data you are looking for. Don’t forget to check for metadata so you have some provenance for your data.

Data Repositories

Data repositories are places that store data.  Many public repositories are themed by subject or by the entity that produces the data.  For example, many California counties, the State of California, and the federal government have their own repositories for GIS data, including repositories for specific agencies.  Data Basin is an example of subject-specific repository that focuses on data for environmental stewardship.

Academic Publications

Researchers in your field may be using datasets that are useful for your research.  Read the methods section and citations list to look for sources of datasets and links to how to access the data.

Ask for help

On campus, talk to the Library’s GIS Data Curator or ask on the Geospatial email list.  If the data you need is from a particular place, such as a county or conservation organization, you may be able to contact the organization’s GIS, data, or IT staff to ask about the availability of data.  Additionally, posting in online forums (such as the aforementioned Stack Exchange), websites, or social media using keywords that describe the data you need (see the discussion above about synonyms) and hashtags to get a broader audience can be fruitful.

Drop-In Hours

The UC Davis DataLab provides weekly Drop-In Hours. This time is set aside for any and all questions about spatial data, from simple to complex, as well as other data science topics.

Email Lists

UC Davis affiliates can sign up for email lists through the UC Davis Information & Educational Technology’s Sympa list serve manager.  The “Geospatial” email list is a widely-used list for UC Davis faculty, students, staff, and local community members who work with any type of geospatial data.  The list can be used for announcements or questions.

Geospatial Software

The geospatial industry has a number of established, well-respected, and long running free and open source projects that may suit the needs of researchers and students.  The Open Source Geospatial Foundation oversees many of these projects, including QGIS (which runs on Mac, Linux, and Windows).

Esri’s ArcGIS suite of software is available to any UC Davis affiliate. Information on product availability, and licensing guides can be found at http://arcgis.ucdavis.edu

GIS Workstation

The lower level of Shields Library has one GIS workstation that UC Davis students, faculty, researchers, and other staff may to use for a maximum of two hours per day. The workstation room is located near, but outside the Map Room and is open the same hours as the Library. The workstation has the full suite of ArcGIS 10 software (available to campus affiliates) and QGIS 3 (available to anyone).

An 11″ x 17″ color scanner is available for maps and aerial photography.

Workstation use must comply with UC Davis Computer Use Policies and the Library Computer Use Policy as well as the following guidelines:

• GIS software and data licensed by the library may not be used for commercial purposes.
• Software and spatial data may be licensed and subject to restrictions on who can use it and how it can be used. We provide GIS users with public domain data and any other data and software that we can under the terms of the licenses.
• It is advisable to save your data and project files to portable media.

Will you be starting a project from scratch that will require your attention for months, even years OR are you continuing a project started by somebody else?

The Data Management Program is here to help make both of these situations less painful. We can help you with

• Organization: keep track of your files so that you know what is in them
• Consistent data entry: design data collection forms in such a way that everybody doing the same experiment records the results the same way every time
• Database structure: move from unwieldy spreadsheets to databases
• GIS and maps: consult with our GIS expert on all stages of a project that includes geospatial data, from planning to creating interactive maps.
• Finding data: not all data sharing portals are obvious, and we can help with that.
• Cleaning data: stop doing repetitive copy/paste; check out some of our workshops to find a better way
• Getting credit for data: get your dataset noticed and cited by placing it in the right data repository

Note: many funding agencies require that you provide open access to your data!

For more information, visit our website or contact us at dataserv@ucdavis.edu