Python Script to Generate a Scrolling Video showing a Before and After Comparison for use on Maps, Roads, etc.
The idea was inpired by this excellent video by Troy Sankey from Strong Sactown who produced a guide on how they made it here.
This in turn was inspired by Segregation By Design.
The script this video produces is a lot less flashy, but useful for a simple before and after comparison.
Instagram post: https://www.instagram.com/p/C77oHi0yvYP/
The Township of Langley released a large JPEG file that showed the entire length of road to be improved. The original image is available here and the website about the project is here.
Rotating the image 90 degrees and resizing it to 1080 pixels wide, it was possible to create a large image that can be panned vertically for a social media video. This was done to create corridor_vert_1080_after.png.
Creating the before map image, corridor_vert_1080_before.png was done by connecting QGIS to the Township of Langley's ARCGIS server and exporting a large image of the area at 1:400 scale, and then adjusting the rotating and size to match the after image.
To create the illusion of one road "painting over" another, both images are scrolled simultainously until they reach the bottom. A seperate fade loop is done to wipe the rest of the after image over the before image, as if the camera has stopped while the painting over continues.
- Install the latest version of python.
- After install, open a command line and type the following:
pip install opencv-python(if this doesn't work you may need to change to the Scripts folder in the Python install folder first) - After install, double click the scroll_videos.py script
The script was created using ChatGPT's 4o model as of 2024-06-06. chatgpt_log.html is the record of the conversation.