MATLAB: Scxsc Mapping Toolbox, Can the Precision Change

Mapping Toolboxscxsc

The scxsc function in the Mapping toolbox is a function that I have quickly tested and found it is well suited for my application.

However it only outputs 4 digits after the decimal leaving an uncertainty of +/-10 meters with those resulting coordinates which is not acceptable for my application. Is there any way to have it output additional significant figures after the decimal? The initial coordinates and circle radii are all accurate to 6 digits after the decimal and I would like to retain this precision.

Best Answer

At the command line, give the command

format long g

and then display the output variables again. You will see that they have more than 4 digits precision: it is just that the format you are using only displays 4 digits.

Related Solutions

MATLAB: How to decrease precision

You cannot tell MATLAB to use an arbitrary lower or higher precision. At most, you can work in single precision instead of double. But even there, you need to be careful, as all numbers by default are ALWAYS doubles. So it would be possible to introduce doubles into the problem, thus to accidentally suddenly start working in double precision. Luckily, singles tend to propagate.

A = single(2) + double(3)
A =
  single
     5

Can you do more than that? This is difficult if you choose to force yourself to work with the standard MATLAB numeric data types. I suppose you could download my HPF toolbox from the file exchange. So, in HPF, if I want to force all computations done in that tool to use EXACTLY 7 decimal digits, then I could do this:

DefaultNumberOfDigits 7 0
x = hpf(pi)
x =
3.141593

That will cause all numbers created as HPF to display and store only 7 digits, with no hidden (i.e., guard) digits carried in the background, and that setting will persist until you change it, even if you exit MATLAB and restart.

https://www.mathworks.com/matlabcentral/fileexchange/36534-hpf-a-big-decimal-class

And, of course, you can also work with the symbolic toolbox.

MATLAB: FileExchange: Zip, Toolbox, App

I got a good answer from the support (after some discussion why they should help me although my Matlab subscription has expired...):

---------------------

Dear William,

This is XXXXX from MathWorks Technical Support, writing in reference to your Case #XXXXXXX regarding 'File Exchange Support needed'.

After working on this use-case with our Development team here are some information provided from their end that will be helpful to you in this regard.

1) To answer your question regarding people using older versions of MATLAB depends on how you define “old MATLAB releases. Based on your File Exchange entry, it looks like your app supports R2010a and above.

2) Unfortunately, the best support that we can provide today is suggest you to:

a) Lay out the files in a way that makes them work for users with R2010a-R2012a.

b) Package the app as an .mlappinstall file (William already does this).

c) In MATLAB, package all the code as a toolbox. The toolbox packaging UI should detect the .mlappinstall file and include it in the toolbox.

d) Upload the toolbox to File Exchange. File Exchange will offer the code as either a toolbox or a zip.

3) For PIVlab users:

a) Users with R2010a-R2012a should download the zip and use the unpackaged source code.

b) Users with R2012b-R2104a should download the zip and install the .mlappinstall file.

c) Users with R2014b and later should download and install the toolbox. Installing the toolbox will also install the app into the App Gallery.

Kindly note that there is a key difference between this process and what you are doing today (allowing File Exchange to create the toolbox file). If the toolbox is packaged in MATLAB, you can select the app in the packaging UI, which will auto-install the app when users install the toolbox.

Also, cc'ed in this email is XXXXX from Online Developer Workflows & File Exchange Team, whom can directly reach out to next time, when you have any questions regarding your File Exchange Submission.

As mentioned in my earlier email, as a frequent File Exchange user and contributor I see the importance of your request and me along with my team collaborated with the corresponding Developers to bring to you this information. I believe this helps you in keep contributing to our MATLAB community.

Once again, a gentle reminder about your license #XXXXXXX which is out of maintenance.

Best Answer

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MATLAB: How to decrease precision

MATLAB: FileExchange: Zip, Toolbox, App

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