How to replace NaN values with 0 of a GRIDobject?

Hello

I have a raster and I imported it on Matlab as GRIDobject but it contains NaN and some values.

I want to change those NaN values with 0; and maybe if it is possible to create a logical GRIDobject

I have tried A(isnan(A))=0; command but is showing error because it isn't a matrix but a GRIDobject.

can anyone help me out this?

Thanks

[Jonas]

where did you find those GRIDobjects? a quick googling did not yield a suitable result

[rossana napolitano]

STREAMobj Create stream object (STREAMobj)

Syntax

S = STREAMobj(FD,W)

Description

An instance of stream object encapsulate the information on geometry

and connectivity of a stream network based on the flow direction of a

digital elevation model and a logical raster that indicates the

position of streams. STREAMobj provides access to various methods

that investigate properties of a stream network and associated data.

Input arguments

FD instance of flow direction object (FLOWobj)

W logical grid (GRIDobj) that indicates stream locations (e.g.

obtained from thresholding the flow accumulation raster)

My goal is to use a streamnetwork shapefile as W to create a new streamnetwork S. I rasterized it and I modified it to create a logical raster; then I import it to Matlbal as a GRIDobj. The problem comes out with the function S = STREAMobj(FD,W) because of the presence of NaN values instead of value 0.

Thank you!

[Wolfgang Schwanghart]

Dear Rossana,

it might be better to ask TopoToolbox-related questions here: https://github.com/wschwanghart/topotoolbox/discussions

Best regards, Wolfgang

Answer 1

[Cris LaPierre]

The TopoToolbox is not created by MathWorks.

A quick look at the list of toolbox functions leads me to suggest looking into the isnan or inpaintnans functions that come with the toolbox. Both accept a GRIDobj as input.

function I = isnan(DEM)
% returns array elements that are NaNs as logical grid
%
% Syntax
%
%     I = isnan(DEM)
%
% Description
%
%     overloaded isnan for GRIDobj. 

.

function DEM = inpaintnans(DEM,varargin)
%INPAINTNANS Interpolate or fill missing values in a grid (GRIDobj)
%
% Syntax
%
%     DEMf = inpaintnans(DEM,type)
%     DEMf = inpaintnans(DEM,type,k)
%     DEMf = inpaintnans(DEM,type,k,conn)
%     DEMf = inpaintnans(DEM,DEM2)
%     DEMf = inpaintnans(DEM,DEM2,method)
%     DEMf = inpaintnans(DEM,DEM2,'tt','fit',1,'eps',20)
%
% Description
% 
%     inpaintnans fills gaps in a grid (GRIDobj) generated by measurement
%     errors or missing values. The user may choose between different
%     techniques to fill the gaps. Note that the algorithm fills only
%     pixels not connected to the DEM grid boundaries.

[rossana napolitano]

Thank you so much :)