Contents
How to convert contours to shapes in Python?
But that difference is even less noticeable as I use more contours, e.g. 1000: The final bit of code is mostly self explanatory: looping over the shapes in the shapefile, then plotting colored polygon patches like in previous posts. The only tricky business is making sure the polygon facecolor matches the filled contour color.
How to create contour polygons with attributes from contour?
In order to create polygons representing the contours we have to close the area somehow. Manually connecting with a new polyline the dangling nodes of the dataset created in STEP 2. For small datasets this might be the quickest solution, but we very seldom work with such small datasets.
What do you mean by contour in GIS?
A contour is a polyline points of equal height. By their nature the contours are polyline features, but many GIS users want to represent the area closed between two adjacent contours with a polygon.
What does ABS mean for contour polygons in Excel?
Polygons that have only one adjacent contour (top ridges, bottom depressions, on the boundary of the dataset) will have Min Elevation = Max Elevation. A polygon for which Abs (Min Elevation – Max Elevation) is greater than the contour interval indicates an error in the process. Analyze the output.
How to save shapely polygons in a list?
The list PolyList now holds a shapely polygon as well as the z-value (or level) of that polygon. In order to use these polygons elsewhere, the easiest thing to do is simply save them within a shapefile. I used the Fiona library for writing, which entails writing the geometry (the polygons) and the properties for each polygon that I stored earlier:
Where can I find a Python test script for shapefiles?
So with that said, here are they python libraries that you’ll need to run my test script: The full code is available in my learning_shapefiles repo and the new script is contourf_to_shp.py.
Is it easy to make shapefiles in dash?
I’m in the process of finishing up a web-app that I’ve written using Dash/Plotly and as someone who is not an expert in front end web development, I’ve really enjoyed how easy it is to build an interactive app without getting bogged down by all the javascript/html/css (though knowing some definitely helps!).