I am using OxyPlot to draw a smooth curve using some input points. I now want to paint the background of the plot depending on the curve. e.g. The rectangle where the curve is below a certain y-value should be painted red, and if it above another specific y-value, the background should be painted green.
For this, I would need some way to get the screen coordinate for any point on the OxyPlot curve? Is this possible?
VB2010 I am using the DataVisualization.Charting.Chart control and am using it as a very crude map of several geographic points. I have that working and it looks good but am trying to see about adding an image to the chart so that it would simulate the land masses. The problem I see is that I zoom around the chart programmatically, so not sure how i can anchor the image to certain x,y coordinates. I don't want to go the whole GIS component as those types of controls are just too much for this fairly simple app.
Update: Well I sort of resolved it. I generated a full world map based on the WGS84 (some would call geographic) projection. This splits the world into perfect 20d x 20d squares. I added this graphic to the BackImage property of my main Chart. I add my points but force the extents of the graph to x: -180 to 180 and y: -90 to 90. Its crude but its actually spot on for my purposes. The only thing that i cant do is zoom in to my points of interest as the background image is static. I wish there was a way to zoom the background image to anchor parts of the image to coordinates on the graph.
I need to make a plot with the cut edges, something like this:
The right and bottom edges should be a polygon, like on a design drawing. No ticks or labels are needed there. No clippings is assumed (actually plot will be strictly inside of the polygon area). Is there easy way for this?
I'm creating heightmaps using Fractal Brownian Motion. I'm then coloring it based on the heights and mapping it to a sphere. My problem is that the heightmap doesn't wrap seamlessly. I've used the Diamond Square algorithm and it's pretty easy to make things seamless using it, but I can't seem to figure out how to do it with fBm and I seem to be having trouble finding an explanation for it on the web.
To clarify, by "seamless", I mean that when I map it to a sphere, it creates a seamless map on the sphere.
Instead of calculating the heightmap per pixel on the heightmap, calculate the heightmap in 3D space based on each point on the sphere and then map that to an image pixel. You're going to have trouble wrapping a 2D, rectangular heightmap like that onto a sphere without getting ugly results at the poles unless you start your calculations from the sphere.
fBM generalizes to 3 dimensions, so given a point on the sphere you can get the height at that point, and then you can do the math to map that value to where it should be stored in the heightmap image.
Or you could use one of the traditional map projections. A cylindrical projection (x, y)->(x, sin y) would give you a seam of just one meridian, which you could rotate to the back. Or you could "antialias" the edge by one or another means.
With a stereographic projection (x,y,z)->(x/(z+1),y/(z+1)), there's only one sour point (the projection point itself).
How do you find the location of the plot area of an axes in figure coordinates or pixel coordinates?
I'm actually trying to capture click and motion events on the x axis area below the plot. So I'm getting an event and trying to test if it's y coordinate is below the plot area. I would think this is simple, but I can't seem to find anything by searching.
SOLVED - found it - wasn't easy to find - axes.bbox.bounds bounds is in pixels, same as the event.