Display of hydrometric data
Philippe GENOUD - LIG STeamer - Université Joseph Fourier - Grenoble - France
The goal is to display in COIN GUI the real-time hydrometric data files that can be found on the Datamart from Environment Canada. The data is provided in a CSV format that contains real-time unit values of water level and discharge for rivers and lakes across Canada. (see http://dd.weather.gc.ca/hydrometric/doc/hydrometric_README.txt)
This page shows various options to display time series data (water level and discharge) measured by hydrometric stations using Google JavaScript APIs for charts.
The data displayed in the following charts correspond to measures of the YT 08AA009 hydrometric station (GILTANA CREEK NEAR THE MOUTH).
It's extracted from the csv file availlable at
http://dd.weather.gc.ca/hydrometric/csv/YT/daily/YT_08AA009_daily_hydrometric.csv.
This file is updated on a daily basis and contains the
last 30 complete days of data plus the current incomplete day. Water Level and discharge are measured every 5 minutes (288 measures by day,
approximately 8600 measures all in all). To display them efficiently we are calculating a mean for every day. For certain days,
measures can be incomplete (less than 288 measures), this is why in the chart we give the number of measures in the tooltip displayed when hovering over
the line chart (see picture below).
Automatic Y adjust vs. fixed Y
Automatic Y adjust
Values of the Y axis are automatically adjusted to the maixmum and minumum value.
The curve is streched.
Fixed Y axis values
Minimum value for Y axis is fixed to 0.
The curve is flattened
Single vs. Dual-Y charts
One measure by chart
The line chart displays only one measure at a time: Water level (meters) or discharge (cubic meters by second) .
Two measures on the same chart
The two series are displayed in the same chart with two independant y-axes: left axis for Water Level, right axis for discharge
Classic vs. Material charts
In 2014, Google announced guidelines intended to support a common look and feel across its properties and apps (such as Android apps) that run on Google platforms. They called this effort Material Design. Google Charts API starts to provide "Material" versions of all core charts (currently beta versions); they look a little be different to classics charts.