# Wolfgang Schwanghart

### University of Postdam

Professional Interests: GIS, Physical Geography, Hydrology, Geomorphology

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**3** Questions

**39** Answers

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**Content Feed**

Submitted

TopoToolbox

A MATLAB program for the analysis of digital elevation models

8 months ago | 67 downloads |

Solved

Create an n-by-n null matrix and fill with ones certain positions

The positions will be indicated by a z-by-2 matrix. Each row in this z-by-2 matrix will have the row and column in which a 1 has...

11 months ago

Solved

Symmetry of vector

Determine whether the vector is symmetric or not (vector could be even or odd in length). For example: x = [1 2 3 3 2 1] ...

1 year ago

Solved

Vector creation

Create a vector using square brackets going from 1 to the given value x in steps on 1. Hint: use increment.

1 year ago

Question

Fit Gaussian mixture model with weighted observations

Hi everyone, looking at the help of fitgmdist, I cannot see that there is the possibility to weight observations. Is there a rea...

2 years ago | 3 answers | 0

### 3

answers2D gaussian filter with a variable sigma

Hi Chad, below is some code that does the trick using nlfilter. To be more efficient, I created a look-up table with a finite s...

2 years ago | 0

What makes a Toolbox a Toolbox, and how is it recognized by Matlab?

Hi Chad, the trick is to have a Contents.m-file in the main folder of your toolbox. In TopoToolbox, the file starts with T...

3 years ago | 0

Submitted

Non-crossing polynomial quantile regression

Non-crossing polynomial quantile regression

6 years ago | 4 downloads |

Submitted

Flow Accumulation (upslope area)

Flow accumulation algorithm that routes through flats

7 years ago | 3 downloads |

Question

Customized icons in workspace

Hi all, I have written a couple of MATLAB classes and, as icing on the cake, I'd like to have customized icons in the worksp...

8 years ago | 0 answers | 1

### 0

answersSolved

index of n in magic(n)

let input=5; magic matrix 17 24 1 8 15 23 5 7 14 16 4 6 13 20 22 ...

8 years ago

Solved

Order of things - 1

Let's assume you have a number of calculations to perform, that depend on each other. E.g. 'A' can be calculated, once the outco...

8 years ago

Solved

Count decimal digits of a number

* Given an integer number you have to return the number of its digits. * For example 248 has 3 digits and 1589 has 4 digits ...

8 years ago

Solved

Check if equal

Return true if all the elements of an nD array are equal, false otherwise.

8 years ago

Solved

Add a row of zeros on top of a matrix

Given a matrix, insert a row of zeros as the top row.

8 years ago

Solved

Too Many Zeros, Dump Them!

Sometimes when I create a matrix, I use this syntax: a = zeros(1000,1000); But when the function ends, I find that I don'...

8 years ago

Solved

Enlarge array

Given an mxn numeric array (A) and a 1x2 vector (sz) indicating the dimensions [p q] to enlarge each element, return an (m*p)x(n...

8 years ago

Solved

Pascal's pyramid

In Pascal's triangle each number is the sum of the two nearest numbers in the line above: 1 1 1 ...

8 years ago

Solved

Create an index-powered vector

Given a input vector x, return y as index-powered vector as shown below. Example x = [2 3 6 9] then y should be [...

8 years ago

Solved

Matrix to column conversion

Given a matrix of any size, convert it into a column vector. e.g A=[10 20 30; 40 50 60] then, B = [10; 40; ...

8 years ago

Solved

Find the index of the largest value in any vector X=[4,3,4,5,9,12,0,4.....5]

The given function returns the index of the maximum value in a given matrix. such as X=[4,3,4,5,9,12,0,5] Ans= 6 if maxim...

8 years ago

Solved

Free passes for everyone!

_Simply return the name of the coolest numerical computation software ever_ *Extra reward* (get a _freepass_): As an addit...

8 years ago

Solved

Number of digits in an integer

Specifies how many digits in a given integer. Example: in=100 ==> out=3

8 years ago

Solved

Generate a NaN...on purpose

The goal is to create a function that will return a single "NaN" without using the nan function. I am interested to see how many...

8 years ago

Solved

Finding peaks

Find the peak values in the signal. The peak value is defined as the local maxima. For example, x= [1 12 3 2 7 0 3 1 19 7]; ...

8 years ago

Solved

Find smallest integer type to accommodate your number

MATLAB supports 1-, 2-, 4-, and 8-byte storage for integer data. Find the smallest integer type to accomodate a scalar integer. ...

9 years ago

Problem

Find smallest integer type to accommodate your number

MATLAB supports 1-, 2-, 4-, and 8-byte storage for integer data. Find the smallest integer type to accomodate a scalar integer. ...

9 years ago | 3 | 25 solvers

Solved

Max index of 3D array

Given a three dimensional array M(m,n,p) write a code that finds the three coordinates x,y,z of the Maximum value. Example ...

9 years ago