polygon

I am working on a project where I am using a shape file to make a choropleth map of the United States. To do this, I downloaded the standard shape file here from the US Census Bureau. After a little bit of cleaning up (there were some extraneous island territories which I removed by changing the plot's axis limits), I was able to get the contiguous states to fit neatly within the bounds of the matplotlib figure. For reference, please see Edit 4 below.

Edit 1: I am using the cb_2018_us_state_500k.zip [3.2 MB] shape file.

The only problem now is that by setting axis limits I now am no longer able to view Alaska and Hawaii (as these are obviously cut out by restricting the axis limits). I would now like to add both of these polygons back in my map but now towards the lower part of the plot figure (the treatment that is given by most other maps of this type) despite its geographical inaccuracy.

To put this more concretely, I am interested in selecting the polygon shapes representing Alaska and Hawaii and moving them to the lower left hand side of my figure. Is this something that would be possible?

I can create a Boolean mask using:

I have a question concerning rasterization of polygons by maximum overlap, i.e assign the value of the polygon that has the highst area overlap with the raster cell.

The real world exercise is to rasterize polygons of soil-IDs in R, in order to produce relatively low resolution maps of soil properties as model inputs.

The problem is that the rasterize() function of the terra package (and similar stars' st_rasterize()) assigns the cell value from the polygon that contains the cell midpoint. If a raster cell contains multiple polygons, I would rather like to select the value of the polygon (soil-ID), which has the highest aerea cover in a raster cell.

Here is a small self-contained example that visualizes my problem, using terra.

I've built this new ggplot2 geom layer I'm calling geom_triangles (see https://github.com/ctesta01/ggtriangles/) that plots isosceles triangles given aesthetics including x, y, z where z is the height of the triangle and the base of the isosceles triangle has midpoint (x,y) on the graph.

What I want is for the geom_triangles() layer to automatically provide legend components for the height and width of the triangles, but I am not sure how to do that.

I understand based on this reference that I may need to adjust the draw_key argument in the ggproto StatTriangles object, but I'm not sure how I would do that and can't seem to find examples online of how to do it. I've been looking at the source code in ggplot2 for the draw_key functions, but I'm not sure how I would introduce multiple legend components (one for each of height and width) in a single draw_key argument in the StatTriangles ggproto.

I need some hints on this one:

A polygon P is star-shaped if there exists a point p in the interior of P such that any other point (vertex) on the boundary is visible to p.

Given a polygon P, how can i determine if P is a star shaped polygon?

Time complexity should be o(n) on average.

Ive been sitting on this for a while now, Any help will be appericiated.

This is a bit harder to explain than my last question because the problem is not exactly reproducible.

I am producing legends for a couple of maps and am drawing a box around both legends since one has only 1 item (a line feature) and the others are discrete fills (a polygon feature). Using geom_sf to plot both.

I end up with a weird artefact that looks like part of the lines are drawn twice with just a slightly shifted position.

I managed to produce a similar error with the iris dataset where legend.box.background is only partially drawn.

On a website I'm creating there is a cursor that needs to change its color smoothly.
When it is on a white background the cursor needs to be the blue #0059ff (this is important and I will explain why later on) and when it is on blue then the cursor needs to be white; and the transition needs to be smooth like so:

To get the white color with mix-blend-mode I'm calculating the inverted color using adjust-hue($color, 180) (in SCSS) and applying this color to the cursor.

When the background color is #0000ff then cursor should be #ffff00.

I have started a prototype using mix-blend-mode: difference that works on "primary colors" (basically colors like #ff0000, #ff00ff and so on).
Result:

Problems begin when I try to change the "primary" blue #0000ff to the one needed by the project #0059ff. The inverted color is calculated to be #ffa600 and the result is, let's say, "unsatisfactory" because I want the cursor to be white on some background color and said color on white background.

Calculating the difference will not work with this color and I have no idea how to make it so that when the cursor is not over the white background then the cursor becomes blue (-ish) and when it's over the blue background it becomes white.

My whole code so far:
(SCSS compiled so it can run in StackSnippet)

As a follow up to this famous thread. I decided to ask a new question because this is more specifically for vertical legends, and the given answers still don't provide a fully satisfactory solution. For polygon key glyphs, there was a suggestion to increase the size of the margin between the actual polygon glyph and the key border, with a modification of the underlying draw_key function. However, this doesn't really work if I want to keep a border, e.g., in black.

And when using other geoms (e.g., geom_line), I don't even see how to increase the margin between glyph and border - on a brief glance at the draw_key function used in ggplot2:::GeomLine (it doesn't use an exported draw_key function), it is not clear to me where to modify this.

So, my question is if there is a way to change the actual space between the key glyphs that would allow to keep a border (e.g., color = "black"), and without increasing the glyph size.

Without using ggplot2 or other plotting libraries, I would need to draw circles around a polygon/star chart vertices, i.e. each circle with a radius equal to the respective polygon radius. You can see an example here:

Here is a simple shiny app: