interpolation

Interpolating Gridded 3D Data to a finer scale

断了今生、忘了曾经 提交于 2019-12-06 10:37:21
I have a NetCDF file of a probability surface. It's a 30x30 grid of 0.25 degree lat/lon intervals with a probability surface described in the z dimension. I can easily import this into Panoply, a NetCDF viewer: And it's then a breeze (checking one box) to interpolate/smooth the raw data to a finer grid size: However, I don't just want to visualize the data, I want to plot it in R along with bathymetry and point data. That all is no problem, but I have not found a straightforward way to interpolate the gridded data in R. Here's the code I use to import and plot the data: library(RNetCDF) nc <-

Finding 3 dimentional B-spline controll points from given array of points from spline solution?

被刻印的时光 ゝ 提交于 2019-12-06 10:32:52
问题 Wa are talking about Non-uniform rational B-spline. We have some simple 3 dimentional array like {1,1,1} {1,2,3} {1,3,3} {2,4,5} {2,5,6} {4,4,4} Which are points from a plane created by some B-spline How to find controll points of spline that created that plane? (I know its a hard task because of weights that need to be calculated but I really hope it is solvable) For thouse who did not got idea of question - sory my writting is wwbad - we have points that are part of plane rendered here and

Alternatives to scipy.interpolate.griddata that don't hang on aligned points

岁酱吖の 提交于 2019-12-06 10:30:34
I have a point dataset that I'm trying to interpolate on a grid. These points are aligned in grid fashion with some points missing see below: To complicate it, it's possible that other input pointsets may not align on a grid, so I'm trying to use scipy.interpolate.griddata to interpolate these values onto a regular grid. However, sometimes my underlying grid aligns perfectly with the sampling rate of the input point dataset and griddata hangs. According to this question scipy.interpolate.griddata operates poorly if the sample occurs across 3 points that are perfectly aligned which sometimes

matplotlib: coloring line plots by iteration-dependent gray scale

夙愿已清 提交于 2019-12-06 09:48:55
Relative programming newbie here. I have trouble figuring out how to plot interpolated functions over a series of iterations, where as the iteration index increases, the plot would go from black to gradually lighter shades of grey. For example, import numpy as np import matplotlib.pyplot as plt from scipy.interpolate import interp1d for t in np.arange(0.,2., 0.4): x = np.linspace(0.,4, 100) y = np.sin(x-2*t) + 0.01 * np.random.normal(size=x.shape) yint = interp1d(x, y) plt.plot(x, yint(x)) plt.show() produces I would like the blue sinusoidal function to be black, and the rest becomes lighter

PCM algorithm for upsampling

杀马特。学长 韩版系。学妹 提交于 2019-12-06 09:25:12
问题 I have 8k16bit pcm audio and I want to upsample it to 16k16bit. I have to do this manually. Can someone tell me the algorithm for linear interpolation? Should I interpolate between each two bytes? Also when I upsample i have to make changes for the wav header - what should I change? 回答1: As others have mentioned, linear interpolation doesn't give the best sound quality, but it's simple and cheap. For each new sample you create, just average it with the next one, e.g. short[] source = ...;

Pandas.DataFrame interpolate() with method='linear' and 'nearest' returns inconsistent results for trailing NaN

独自空忆成欢 提交于 2019-12-06 09:13:18
问题 I was exploring pandas.DataFrame.interpolate() with different methods, linear vs. nearest , and I found different outputs from the two methods when there is missing data at the trailing. For example: import pandas as pd # version: '0.16.2' or '0.20.3' >>> a = pd.DataFrame({'col1': [np.nan, 1, np.nan, 3, np.nan, 5, np.nan]}) Out[1]: col1 0 NaN 1 1.0 2 NaN 3 3.0 4 NaN 5 5.0 6 NaN >>> a.interpolate(method='linear') Out[2]: col1 0 NaN 1 1.0 2 2.0 3 3.0 4 4.0 5 5.0 6 5.0 >>> a.interpolate(method=

OpenGL Color Interpolation across vertices

假装没事ソ 提交于 2019-12-06 08:42:46
Right now, I have more than 25 vertices that form a model. I want to interpolate color linearly between the first and last vertex. The Problem is when I write the following code glColor3f(1.0,0.0,0.0); vertex3f(1.0,1.0,1.0); vertex3f(0.9,1.0,1.0); . .`<more vertices>; glColor3f(0.0,0.0,1.0); vertex3f(0.0,0.0,0.0); All the vertices except that last one are red. Now I am wondering if there is a way to interpolate color across these vertices without me having to manually interpolate color (instead natively, like how opengl does it automatically) at each vertex since, I will be having a lot more

interpolate points on a height map

别来无恙 提交于 2019-12-06 07:01:38
I have some values (bytes) over a plane evenly distributed (the come from real measures) like for instance temperature. I'm trying to generate the whole surface. But I'm not successful. The main condition is that the number and position of the points will not be known and that the surface MUST keep the value in the points where is measured and the points in between will be interpolated. Ideally, if only one point is set the final surface should be a mountain. By the way, and just in the case that it may help. Im coding it on WPF (C#) and it would nice to not involve heavy libraries or whatever

Flipping issue when interpolating Rotations using Quaternions

☆樱花仙子☆ 提交于 2019-12-06 06:49:26
I use slerp to interpolate between two quaternions representing rotations. The resulting rotation is then extracted as Euler angles to be fed into a graphics lib. This kind of works, but I have the following problem; when rotating around two (one works just fine) axes in the direction of the green arrow as shown in the left frame here the rotation soon jumps around to rotate from the opposite site to the opposite visual direction, as indicated by the red arrow in the right frame. This may be logical from a mathematical perspective (although not to me), but it is undesired. How could I achieve

Interpolation through fourier space padding

风格不统一 提交于 2019-12-06 06:38:06
问题 I recently tried to implement on matlab a simple example of interpolation method using zéro padding in the fourier domain. But I am not able to get this work properly, I always have a small frequency shift, barely not visible in fourier space, but thay generates a huge error in time space. As zéro padding in the fourier space seems to be a common (and fast) interpolation method, I assume that there is something I am missing: Here is the matlab code: clc; clear all; close all; Fe = 3250; Te =