What’s a Temperature-Salinity plot?

Temperature-Salinity plot

As a visualization engineer at Planet OS, I learn new things everyday. My job is to get just enough domain specific knowledge to come up with visual solutions. This week I learned what is a Temperature-Salinity (T-S) plot.


Here’s a definition of what you can use a T-S plot for (from the same textbook as the image above):

“Plots of salinity as a function of temperature, called T-S plots, are used to delineate water masses and their geographical distribution, to describe mixing among water masses, and to infer motion of water in the deep ocean. Here’s why the plots are so useful: water properties, such as temperature and salinity, are formed only when the water is at the surface or in the mixed layer. Heating, cooling, rain, and evaporation all contribute. Once the water sinks below the mixed layer, temperature and salinity can change only by mixing with adjacent water masses. Thus water from a particular region has a particular temperature associated with a particular salinity, and the relationship changes little as the water moves through the deep ocean.”

We had the need to plot temperature and salinity as a function of pressure (which could also be used to infer depth). As Ryan Abernathey kindly mentioned, this chart is different from a T-S plot. The image above shows a T-S plot on the right and a plot of temperature and salinity over pressure on the left. My goal was to reproduce the left one, inspired by the chart from this paper starting from this dataset.


From the visualization standpoint, we can see two lines: one for salinity and one for temperature, both on the X axis, while pressure is on the Y axis. I like to see them as sensors dropped from a boat, coming down the water column, then moving back up, getting measurements along the way. That’s why we can see these two lines making a round-trip from top to bottom and back.

The chart implemented can be zoomed and panned which is useful to better see some intricate patterns. One interesting feature I don’t get to implement often is multiple axes. The creator of ggplot2 (the best charts library IMO), Hadley Wickham, has some strong arguments against multiple axes. We could certainly discuss alternatives, like small multiples or some linked scatterplots, but T-S plots are the tool these experts are used to use. And my opinion is that the best tool in the world is less useful than the tool we already master.

Go try it out here! This T-S plot and many others are part of some upcoming features we will announce soon. So stay in touch!

Chris Viau
Data visualization engineer at Planet OS

A Brief Intro to Visualizing Datasets on a Heatmap with Cirrus.js

We launched Cirrus.js a few weeks ago to share some of the visualization technologies we are developing here at Planet OS. We recently encountered the need to visualize some datasets on a heatmap, so we added one to Cirrus.js.


So what is a heatmap? And what kind of data can it visualize? One of the challenges of building a tool to index all environmental sensor data is that we have to work with a huge variety of data formats and structures. One of these structures is two dimensional data (2D data). We tend to understand 2D data as any data that can fit on a table, where each cell being at the intersection of a row and a column contains a value. But 2D data can mean multiple things, and only some 2D datasets are suitable for a heatmap. Let’s give some examples from the environmental sensor data we work with on a daily basis at Planet OS.

Planet OS and TCarta Marine Deliver On-Demand Shoreline and Bathymetry Data

TCarta Data Marketplace

Planet OS and TCarta Marine are excited to announce the launch of the TCarta Data Marketplace, an online storefront that provides on-demand access to TCarta’s bathymetry and shoreline data products.

“We are excited for the launch of the Data Marketplace and believe it will be a great tool for our customers to search, preview, and order bathymetry data in an efficient and easy to use manner.” Says Kyle Goodrich, President TCarta Marine LLC.

Planet OS Hires Big Data Expert Tom Faulhaber as Chief Technology Officer

Tom Faulhaber

Planet OS is pleased to announce it has hired Tom Faulhaber as its Chief Technology Officer based in the San Francisco Bay Area. Tom is a software industry veteran who brings over 30 years of experience in leading and consulting product development teams.

He has previously worked on industry-leading data products in such diverse areas as massive geospatial-temporal big data at SpaceCurve, scientific visualization at AVS (the Application Visualization System), video intelligence at 3VR, e-Commerce at Staples and cloud-based business intelligence at Certive (now Cloud9 Analytics).

How to Build the Google for Earth Data

I gave a talk yesterday at the 2015 Extremely Large Databases (XLDB) Conference at Stanford University focusing on the potential solutions to organizational and technical challenges presented by the NOAA Big Data Project. The Conference is targeted at fostering discussions around real-world challenges, practical considerations, and nuts-and-bolts solutions in the realm of analyzing and managing large datasets. We were honored to be able to sponsor the event and share some of the work we have been doing.


At the New Big Data Ecosystem session of XLDB 2015.

Christophe Viau: From Arts & Biology to Big Data Visualization


Christophe Viau taking a musical break from D3.js.

Earlier this year we were excited to welcome data visualization engineer Christophe Viau to Planet OS. He brings extensive experience building visualization platforms and chart libraries for Datameer, Plotly and Boundary while remaining an active leader and lecturer in the D3.js community. His recent book entitled “Developing a D3.js Edge” was released in 2013 and serves as a demonstration of how to build a chart library with D3.js. We asked Christophe a few questions about how he came to make a career in data visualization and what trends he sees in the industry more generally.

Planet OS Joins Amazon Web Services in Data Discovery for NOAA’s Big Data Project

Unleashing the power of NOAA’s data for economic growth and understanding the Earth

SUNNYVALE, CALIFORNIA, April 21, 2015 – Planet OS is honored to join Amazon Web Services (AWS) as a member of their Data Alliance within NOAA’s Big Data Project announced today. The company will work together with The Weather Company and ESRI under the Cooperative Research and Development Agreement (CRADA) to research and test solutions for bringing NOAA’s vast information to the cloud where both the public and industry can easily and equally access, explore, and create new products from it, thus fostering new ideas and spurring economic growth.

Final NOAA blog post image

Planet OS Director of Federal Operations Randy Ridley Explains How The Government Approaches The Cloud, Sensor Data, and IoT

Randy Ridley has been in charge of Federal Operations at Planet OS managing our business for the federal government since the first days of 2015. Randy brings with him three decades of experience inside the Washington Beltway as a seasoned executive with a proven track record of deploying enterprise software and technology solutions. We asked Randy a few questions to better understand how the federal government approaches enterprise software, the Internet of Things, and sensor technology.

Randy Ridley stands at Vienna Centennial Park in Vienna, VA.

Randy Ridley stands at Vienna Centennial Park in Vienna, VA.

Data engineers Christophe Viau and Andres Luhamaa join Planet OS

Christophe Viau (left) and Andres Luhamaa (right).

Christophe Viau (left) and Andres Luhamaa (right).


The year is off to a great start for Planet OS engineering. Christophe Viau, one of the leading members of the global D3.js data visualization community, joins us as a Data Visualization Engineer. We have also brought on Andres Luhamaa as a Data Integration & Quality Assurance Engineer to utilize his expertise in climate modeling and weather systems. Read on to hear more about what they’ve accomplished and why they decided to join our team:


Christophe Viau joins Planet OS as a Data Visualization Engineer based out of Montreal, Canada. He has previously built visualization platforms and chart libraries for Datameer, Plotly and Boundary while also having interned at SAP. He remains very active in the D3.js community as a lecturer and event organizer. His recent book entitled “Developing a D3.js Edge” was released in 2013 and serves as a comprehensive guide for intermediate-to-advanced D3.js visualization techniques. Christophe obtained his PhD in Software Engineering from École de Technologie Supérieure in Montreal, specializing in information visualization. He also holds a Masters degree in arts and biology. He is joining Planet OS to solve the challenges of visualizing massive multidimensional datasets and to have a direct impact on environmental causes.

Andres Luhamaa will work on data integration and advancing data quality assurance based out of Tartu, Estonia. Previously, he worked in the Estonian Weather Service as head of the numerical modeling department and was responsible for local numerical weather prediction system and interpretation of the remote sensing data, including meteorological satellites and radars. Andres has also worked as a researcher at the University of Tartu in its laboratory of atmospheric physics where he developed high-resolution numerical weather prediction models as well as computed regional re-analysis databases and future Estonian climates. Andres received BSc and MSc from University of Tartu in environmental physics and will concurrently be pursuing his PhD. He believes that by joining Planet OS he can contribute to creating new technologies for collecting and analyzing environmental data.