Interpolating weather maps
After seeing changes as these weather maps update I thought it would be nice to create a sequence out of them. I started with writing a simple script that captures the image at regular intervals. Then later these images were combined into a movie. But this is not a flexible solution so I started something else.
The first result is NL Mapper, a page that can render a colored map of The Netherlands based on a number of measurements. The image is generated in the browser, using kriging.js to calculate the color values.
Updates
August 1
- The maps Regen and Temperatuur (Buienradar) are gone. The first one because the rain data contained too few actual measurements to render a realistic map.
And because the Buienradar temperature data is a copy of the KNMI data I also removed that one. - The page remembers the map you last viewed and will open with it on your next visit.
- A basic sanity check is done on the retrieved data. I noticed a measuring station that often reported a temperature several degrees higher then all surrounding stations. This influences the map in a way I believe is an error. So now only values within 3 standard deviations of the complete data set are included in the map.
- To speed up rendering only the data for the maps you view are retrieved.
August 4
- Two new maps: Hitte-index showing the heat indices, and Gevoelstemperatuur (windchill) with the wind chill indices.
August 16
- There's a new map, Luchtkwaliteitsindex, that shows calculated air quality indices based on concentrations of nitrogen dioxide, ozone and particulate matter (PM10 and PM25).
- The maps can calculate all intermediate colors.
- Contour lines can be hidden.
- Some modifications to the colors of the maps.