This document summarizes a project investigating the use of GIS software for weather forecasting applications. The project was completed for Scotia Weather Services Inc., which provides weather forecasting services and wants to use GIS to analyze how weather events could impact the power grid. The project used QGIS and ArcGIS to process wind speed data into maps of wind gust speeds at power line pylon heights. The outputs identified regions where wind speeds exceeded thresholds that could affect transmission lines. While QGIS is free and open source, the analysis found ArcGIS scripts were more stable and better documented than PyQGIS scripts.

1. INVESTIGATING THE USE OF
GIS SOFTWARE FOR WEATHER
FORECASTING APPLICATIONS
COMPLETED FOR SCOTIA WEATHER
SERVICE INCORPORATED

2. Enough about me, let’s talk about Q’
• Background
• Goals
• Software used
• Methods
• Outputs
• Analysis

3. Acknowledgements
• David Coleville (Supervisor)
• Mark Hebert
• Trevor Milne

4. BACKGROUND

5. Scotia Weather Services Incorporated
• Based out of Dartmouth
• Provides weather forecasting and environmental
consultation services to a wide variety of clients.

6. Scotia Weather Services Incorporated
• Currently provides Scotia Power with Wind Data.
• Investigating the possibility of using GIS software to
measure to potential effect of weather events on the
power grid.

7. GOALS

8. Goals
• To use scripting in QGIS in order to process data on
forecast wind speed, in such a way as to represent
variations across local regions and their potential effect on
the power grid network.
• Create a parallel set of scripts and models in the ArcGIS
environment in order to compare the functionality of the
QGIS and ArcGIS software packages.

9. SOFTWARE USED

10. QGIS
• The world’s leading open source GIS
• User-friendly interface
• Free!
• Comes with additional open source geospatial software
• GDAL
• SAGA
• Grass
• Currently on version 2.20 (Valmiera)

11. PyQGIS
• Python extension for geoprocessing
• Present in the program since version 0.9
• Can be used in the Python Console
• Interface features an in-program editor

12. PyQGIS

13. ArcGIS
• Industry standard
• Features its own scripting extension ArcPy

14. METHODS

15. Data provided by SWSI
• 48 rasters
• 1 shapefile for Transmission lines from Scotia Power

16. Data Prep

17. Raw Data (Forecast 30)

18. Exclude Zero values
• Null values set as -9.99e+008
• Values under 0 removed using a Con/IfElse statement

20. Recalculating values
• Values only represent surface wind speed
• Needed to recalculate values for
• Wind gust speeds
• Elevation at pylon height (50m)

21. Pylon Wind Gust

22. Excluding Values Under Thresholds
• 60 km/h for sustained wind speeds
• 90 km/h for wind gust speeds

24. Convert Raster to Polygon

25. Clip Affected Transmission Lines

26. OUTPUTS

27. Outputs in PyQGIS vs. ArcPy
• PyQGIS:
• Graphical
• Project Files
• Arcpy
• Graphical
• CSVs

28. Sample Ouput

29. Pylon Wind Forecast AVI for Region 5

30. ANALYSIS

31. Comparing scripts
• PyQGIS
• Five scripts
Two for extent creation
Data processing
Graphic creation
Project creation
• ArcPy
• One Script
• Produced graphics
• CSVS

32. Advantages the Environments
• QGIS
• Free!
• Comes GDAL, SAGA
Grass
• ArcGIS
• Stable
• Well Documented
• Well Supported

33. http://pyqgis.blogspot.ca/

34. Issues with QGIS
• Lack of documentation
• Unstable
• Problems with running scripts multiple times
• User interface malfunctioning

35. Conclusion
• Scripting is definitely a good option for processing
weather forecast data
• PyQGIS dos not match the user friendliness of the QGIS
user interface

36. QUESTIONS?