Keep in Touch with Your Past
By Casey McLaughlin
What happens to collected data? Every day, the world is stockpiling vast amounts of data and often this data has a spatial component tying it to a specific location on the earth. For environmental data, the spatial location is a fundamental component. Geospatial defines the context of a single piece of data and the relationship it has with other nearby data. The general growth in data may seem obvious in our increasingly technical world (smart phones are data making machines). We are very concentrated on collecting data about where we are right now (real time sensors, crowd sourcing, traffic counts). Historical data can and should place newer data in context.
EPA, formed in the early 1970s has collected and maintained a mountain of environmental data. I am familiar with our region’s cleanup program records; along with tabular data (sampling dates, results, QA/QC information) we also collect spatial data in the form of latitude/longitudes, addresses, aerial surveys, sampling plans, excavation maps. Unfortunately, keeping data is not simple. Technology has continuously improved.
Data collection techniques and sensors have advanced. Systems have changed. Data and technology have evolved so that retrieving data from an old database technology may not be possible. How can I get data from a 5 ¼” floppy disk? Think about having a stack of old cassette tapes. How would you get songs into your digital library (easily)? Imagine the label has worn off 100 cassettes – how would you know where a specific song was located on just one of those tapes?
Old data technology is just one of many complications to using historical and modern data. Over the last 15 years, EPA has put forth a tremendous effort in digitizing reports. Certainly electronic record-keeping is superior to paper records???? Don’t get me wrong, electronic records are crucial — hello, I’m an information specialist! Not all electronic formats, however, are appropriate for data analysis. Can you run a correlation between the data in an archived (paper or scanned) report with new data? What about using a FoxPro database stored on a 3 ½” diskette (this happened to me a few years ago and it took me awhile to FIND a machine with a disk drive). How can managers compare post-excavation sampling locations (often represented on multiple versions of a map) with a proposed residential development? What do you do when you encounter an over-sized map which is now in the electronic record as an “Unscanned Item”?
Using data from the past with data from the future is not trivial and geospatial data has some special considerations beyond technology. Resolution of aerial imagery may be coarse, but without a time machine, we don’t have the option of re-acquiring imagery from 1950 (talk to me later about a T.A.R.D.I.S.)! Geo-referencing old photos or CAD drawings can be problematic because of projection complications (oh, what a GIS topic!) and lack of reproducible local control points. Avoiding the gruesome details, properly dealing with old geospatial data requires some thought and expertise.
Keeping data is not the same as being able to use data in the future.
Most every EPA project report has an element of spatial data. Having a map electronically may not be good enough for using it with new data in the future. Properly acquiring spatial data helps make informed decisions now. Properly maintaining and storing spatial data will help make future decisions better.
Casey McLaughlin is a first generation Geospatial Enthusiast who has worked with EPA since 2003 as a contractor and now as the Regional GIS Lead. He currently holds the rank of #1 GISer in EPA Region 7′s Environmental Services Division.
Editor's Note: The opinions expressed in Greenversations are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.