Help

What this viewer shows

This application visualizes climate metrics over Canada as gridded fields, with optional overlays (hydrometric gauges and dam inventories).
Use the sidebar to select a variable, warming level, and summary statistic (where available).

Quick start (recommended workflow)

1. Projection: Choose Equirectangular (fast; geographic lon/lat) or Orthographic (globe view; heavier).
2. Stride: Start with 2 for fast exploration. Switch to 1 for full resolution when finalizing a figure.
3. Variable: Select Precipitation, CIF, or a Design variable.
4. Warming level: Choose the Global Warming Level (°C) to display.
5. Metric / Statistic: Pick the metric and (for ensemble) the statistic (Mean/Median/Q25/Q75).

Only one gridded layer is shown at a time (the most recent active selection).

Controls and interpretation

Projection

• Equirectangular: longitude/latitude view; best for locating features and most comparisons.
• Orthographic: globe view; useful for presentation but slower due to reprojection.

Stride (performance vs detail)

• Stride = 1: plot every grid cell (highest detail; slowest).
• Stride = 2 or 3: decimated plotting for fast interaction (recommended while exploring).

Colour mapping

• Value-based: uses the variable’s native values and units.
• Quantile/Decile: emphasizes spatial rank rather than absolute magnitude.
  • Continuous gradient: maps percentiles to a smooth 0–100% colorbar.
  • Discrete bands: bins values into percentile classes (see below).

Discrete quantile legend definitions

• 5 classes: 0–20%, 20–40%, 40–60%, 60–80%, 80–100%
• 6 classes (robust): 0–2%, 2–25%, 25–50%, 50–75%, 75–98%, 98–100%
• 10 classes: 0–10%, 10–20%, …, 90–100%

Overlays

• Gauges: enable Show gauge locations to display gauge positions.
  If a gauge dataset is selected, marker colours represent the chosen return-level quantile.
• Dams:
  • Ontario dam inventory: Ontario-only points.
  • GDAT inventory: national selection points.

Extracting values at a point (two methods)

The viewer supports two equivalent ways to specify a point of interest.
In both cases, you must click Record point to generate the table.

Method 1 — Manual latitude/longitude input

1. Open Map → Point Selector.
2. Enter Latitude and Longitude under Manual point input.
3. Click Record point.

Method 2 — Click-to-select on the map

1. Open Map → Point Selector.
2. Ensure Click on map to set manual Lat/Lon is enabled.
3. Click on the map; the Latitude/Longitude fields update automatically.
4. Click Record point.

Notes:

• Click-to-select is active only when a gridded layer is displayed (i.e., a variable is selected and the map is “filled”).
• In Orthographic projection, clicks are converted from projected coordinates back to lon/lat internally; the recorded point is always lon/lat.

Where the extracted values appear

Table tab (interactive view)

After you click Record point, the extracted values appear under:
Table → Selected point – ensemble “Mean” values.

The header shows the selected lon/lat and the nearest grid indices (rlat/rlon) used for sampling.

Downloads tab (CSV export)

Download the most recent extracted table from:
Downloads → Download point table (CSV)

The CSV always corresponds to the most recently recorded point.

Tips

• Start with Equirectangular + Stride 2 for responsive exploration.
• If the field looks “washed out”, try Quantile mapping to reveal spatial structure.
• Use Value-based when you need physically interpretable magnitudes and units.

Known limitations

• Some variables have missing values over parts of Canada; these appear as blank/transparent regions.
• Orthographic mode is more computationally expensive due to reprojection and resampling.

Contact Us

We welcome your feedback and questions regarding the Canada Climate Viewer.

Email: ashaygan@uwo.ca

Contact / PI:
M. Reza Najafi, PhD
HydroclimEx Lab
Department of Civil and Environmental Engineering (CEE)
Western University
London, Ontario, Canada

Webtool development:
Afshin Shaygani, PhD
HydroclimEx Lab

Data provision:
Jack William Warden
HydroclimEx Lab

About Canada Climate Viewer

Version: 0.9 Beta (2026)

Technical Overview & Performance

The Canada Climate Viewer is a specialized high-performance visualization tool designed to handle large-scale national hydro-climatic datasets. It is engineered to provide near-instantaneous interactivity for complex spatial data through a multi-tiered optimization strategy:

• Advanced Caching: Utilizes a custom Least Recently Used (LRU) memory cache combined with persistent disk caching to minimize redundant computations.
• Optimized Data Transfer: Implements orjson serialization for high-speed data transmission between the server and the browser.
• Hardware Acceleration: Automatically switches to WebGL rendering for high-density layers to maintain smooth responsiveness.
• Smart Downsampling: Dynamically adjusts grid resolution during interactive panning and zooming to balance visual fidelity with performance.

Developed by: Dr. Afshin Shaygani HydroclimEx Lab, Western University

Data Provision: Jack William Warden HydroclimEx Lab, Western University

Data Index Reference

The tool computes indices for each CRCM5 ensemble member on the native grid, summarized using ensemble statistics for each warming level. Units are reported as either multiplicative change factors (PerChg) or additive changes in base units (e.g., Δdays, ΔdegC).

1. Extreme Precipitation Return Levels (GEV)

2. Annual Precipitation Totals & Maxima

3. Freeze–Thaw Cycles (Surface)

4. Extreme Temperature Range (ETR)

5. Degree-Days & Mean Temperature

6. Wet & Dry Spell Duration

7. Precipitation Frequency & Intensity

8. Percentile-Based Extreme Precipitation