The old adage that a “picture is worth a thousand words” is proven regularly in the GIS and CAD worlds. Technical content is often conveyed much easier with graphics than text.
For scientists and engineers working in areas such as geology, hydrology, and oceanography, the adage takes on another twist, as their data often describes complex concepts that are not visible to the untrained eye. To present these concepts, some have turned to a Colorado firm that develops visualization software for technical professionals. Golden Software, developers of Surfer for mapping and 3D visualization system and Grapher for 2D and 3D graphing, helps present complex data in a variety of ways — including some ways the developers never envisioned.
A contamination plume represented by isosurfaces modeled in Surfer displayed with an orthographic view. Image source: Golden Software.
Richard Koehler, owner and CEO of Visual Data Analytics, has worked as a hydrologist and environmental consultant for more than 40 years, dealing with large datasets on rivers and streams, groundwater, fisheries, and other environmental resources. He has found traditional line graphs limiting in the display of complex data.
Using Surfer, Koehler found he could more clearly present 3D and orthorectified views of graphs instead of 2D line graphs and display patterns. The approach essentially combines mapping and graphing concepts to present more intuitive images.
“We use a GIS framework to overlay time-series data,” said Koehler, noting that the technique is particularly effective when the user wants to see both short-term and long-term trends. “[With traditional graphing techniques], the more data you have, the less detail you can display.”
As an example, Koehler displayed streamflow data for multiple years in a 2D graph, producing a spaghetti-like plot that is difficult to interpret. To improve the view, he displayed the same data in a 3D format, which enables the reader to more readily see patterns separated by year.
A 2D graph can be displayed in 3D to improve readability. Image source: Richard Koehler. Click image to enlarge.
While the 3D graph improved readability, some data remained hidden, so Koehler took the concept a step further. Applying concepts from photogrammetry and remote sensing, he displayed the data in an orthorectified plan view in Surfer, using color coding to display different values in a heat map format. Users can then zoom in on portions of the graph to see daily values or zoom out to see patterns year by year.
Using Surfer, users can create orthorectified heat maps that incorporate time. Image source: Richard Koehler. Click image to enlarge.
The GIS methodology comes into play using Surfer’s capabilities to turn layers on and off, similar to how conventional GIS and CAD users adjust displays by layer in geospatial maps and drawings. “Time makes the perfect X-Y system to show information,” said Koehler. “I’m applying GIS principles as a geo-temporal information system,” he said, citing an example of Arizona river flows overlaid with tropical storms on the same graph. “Surfer makes it easy to create layers on top of each other.”
Surfer enables users to turn layers on and off, as in this display of Arizona river flows overlaid with tropical storm data. Image source: Richard Koehler. Click image to enlarge.
While Golden Software developers did not anticipate Surfer being used in this manner, Koehler’s applications are well aligned with Surfer’s capabilities, according to Zachary Mills, Golden Software CEO. “Our tools help modelers display information in a way that makes sense and can be communicated to stakeholders,” Mills said.
Surfer’s core features are geared to transforming raw data into usable maps with a straightforward interface and wizard tools. It is often used to map geological features, groundwater patterns, and other projects that benefit from visualization of spatial trends.
Surfer enables users to transform into raw data into maps using a wizard. Image source: Golden Software. Click image to enlarge.
While Surfer can be used to produce both maps and graphs, Golden Software’s Grapher tool is even more focused on producing technical graphs. Igor Yashayaev, an oceanographer with Fisheries and Oceans Canada (DFO), has used both Surfer and Grapher in various studies of seawater patterns.
In a recent study of Labrador Sea convection (i.e., mixing) patterns, Yashayaev used Grapher to display how cold water sinks to intermediate and deep layers and spreads across the ocean. Using data from the international Argo program, which collects ocean data using free-drifting profiling floats, along with ship-based observations, Yashayaev documented a 2012–2023 convective cycle, showing that the highest winter cooling occurred in 2015, while the deepest convection occurred in 2018.
Grapher was used to display temperature, salinity, and density patterns for the central Labrador Sea (CLS). Image source: Igor Yashayaev, Fisheries and Oceans Canada (DFO). Click image to enlarge.
“Scientific presentation for me is like art,” said Yashayaev. “You can see the big picture and zoom in to see more detail.” Using Grapher, he was able to create line graphs showing general trends and also include point data showing specific data collected from various sources. In the early 2000s, the advent of robotic data collection equipment drastically increased the amount of data collected, so the ability to see both long-term and short-term data became more important, noted Yashayaev.
Like Surfer, Grapher is adept at producing 3D graphs, but Grapher also provides 70 different graph types, ranging from basic line and bar charts to complex 3D vectors and statistical plots. It has been used for tasks such as updating quarterly reports for a decommissioning project, charting groundwater movement, and analyzing project environmental impacts over time.
Grapher can display in 70 different graph types. Image source: Golden Software. Click to enlarge image.
For users like Yashayaev, the capabilities of Surfer and Grapher simplify tasks that might require complex programming in other products. “You go from raw data to final graphics quickly, and you can tune up graphics for every detail,” he said.
Koehler also uses both Surfer and Grapher. He recently found Grapher useful in displaying river flows in a graph that shows both long-term trends and point data. Specifically, he could display flows the day before and the day after a certain event, such as a flood with a 10% exceedance probability.
Grapher can be used to display line graphs and point data simultaneously. Image source: Richard Koehler. Click image to enlarge.
The latest version of Grapher, released in October, includes new ways to display gradients, adjust histograms, crop images, add plots, edit text, and manage files within a project. Grapher file menus and command ribbons have also been updated to be more consistent with those in Surfer.
Surfer was updated in September to include more than 20 frame templates for map creation. Users can also download georeferenced aerial and satellite images from new online services to add context to maps. Other new features include the ability to copy properties from one visualization to another, as well as new options for displaying compass orientation of models, switching from a default perspective projection to an orthographic projection, and exporting 3D data into formats such as DXF and SHP.
***
If you have GIS-based ideas or projects you think are newsworthy, drop us a line at editors@cadalyst.com.