Contour Series Seems Slow
Posted: Mon May 09, 2011 6:40 am
Hello.
I am attempting to use a contour series to draw a top-down (2D) view of filled contour data. I have a collection of scattered data points that it needs to plot around. There are about 20 of these points.
I have tried calculating the value of the 'missing' points so as to create a complete, irregular grid with the real data points. This sort of worked, but the contours had quite straight edges, even with smoothing enabled. Also something seems awry with how it calculates the gradients - I would often get triangles that would not paint (e.g. they would appear transparent, showing the background). I have found ways to mitigate against these triangles, but I can't seem to find a good solution to get rid of them completely. Is this an error with the contour series itself?
I decided that to improve the contour plot I would calculate every point for a fixed grid, such as every 10 x 10 pixels. This plotted beautiful contours, but as it was adding thousands of points - using the AddXYZ() function - it would take a few seconds to display. This is unfortunately too slow to be acceptable.
I'm trying not to deviate from the natural x,y co-ordinates of the original data points too much, but I'm having trouble finding an approach that plots good-looking and fast contours.
I'm thinking that I will need to try to limit the amount of points I add by doing something clever with an irregular grid, while at the same time trying to keep the x,y co-ordinates of the source data as close to true as possible.
Can anyone please give me some advice on how I could better use the contour series? I'm especially keen to know if there's a way to get rid of the transparent triangles that have been causing me some grief. Any tips on speeding it up will also be greatly appreciated.
I am attempting to use a contour series to draw a top-down (2D) view of filled contour data. I have a collection of scattered data points that it needs to plot around. There are about 20 of these points.
I have tried calculating the value of the 'missing' points so as to create a complete, irregular grid with the real data points. This sort of worked, but the contours had quite straight edges, even with smoothing enabled. Also something seems awry with how it calculates the gradients - I would often get triangles that would not paint (e.g. they would appear transparent, showing the background). I have found ways to mitigate against these triangles, but I can't seem to find a good solution to get rid of them completely. Is this an error with the contour series itself?
I decided that to improve the contour plot I would calculate every point for a fixed grid, such as every 10 x 10 pixels. This plotted beautiful contours, but as it was adding thousands of points - using the AddXYZ() function - it would take a few seconds to display. This is unfortunately too slow to be acceptable.
I'm trying not to deviate from the natural x,y co-ordinates of the original data points too much, but I'm having trouble finding an approach that plots good-looking and fast contours.
I'm thinking that I will need to try to limit the amount of points I add by doing something clever with an irregular grid, while at the same time trying to keep the x,y co-ordinates of the source data as close to true as possible.
Can anyone please give me some advice on how I could better use the contour series? I'm especially keen to know if there's a way to get rid of the transparent triangles that have been causing me some grief. Any tips on speeding it up will also be greatly appreciated.