Archive for the ‘software’ Category

The plot a month later

June 2, 2015 Leave a comment

Over the past month I have worked solid on rewriting the plot facilities


Figure 1, low resolution web image, comparable as shown at the beginning of May except a different geographic projection, done using wildly different software.

This is a quick look at what is new, the full thing is about to be used as part of a major article at the Talkshop.

Why? I was thoroughly fed up with fighting gnuplot, drives many people half crazy trying to get it to do what is wanted, all too often it simply can’t. In this case the final straw was no way of disabling automatic smearing of colour, nor can it draw literal filled polygons. (very amusingly given the authors say it can’t it then when writing out SVG format proceeds to write out filled polygons… can’t make it up stuff)

I was already using GLE, a tool with ancient origins. This will do what I say so all those polygons are drawn one at a time. The whole thing is very complicated, more so since my code writes GLE code and data before passing the whole lot over for plotting (GLE in turn calls ghostscript with postscript code, wheels within wheels)

There is more…

Read more…

Categories: software, temperature

UK outline map and Met Office Datapoint

August 24, 2014 1 comment

I’ve been busy pottering on code as a mindless intermission during house repairs, can only do so much at a time. Argue with a piece of wood or with a computer screen? 🙂


This is a bitmap copy of a map of the UK with markers showing the location of Met Office weather sites with hourly data published via their Datapoint service. Data is under OGL (Open Government Licence) which allows usage. Unfinished work, references are not yet included.

The real file is part of a large PDF (vector format) containing plots for all those stations during a 24 hour period.

Example PDF  (1.2MB, work in progress, more to be done)

Read more…

Categories: software, weather

Hugin and correction of photographic distortion

August 3, 2014 2 comments


Superconducting conductors arriving at Fermilab, credits at end.

None of you will know I have history in photography, award winning, newspaper front page, glossy magazine front page, etc., none earth shattering but it was a personal challenge in the film era. Put another way I have an interest from both the art and technical perspective.

I intended producing a minor blog post on Fermilab and the magnet, ideally posts need a good headline photograph, what with copyright and poor technical standards this is often tricky. My own blog, this one, tends to get poor art.

Read more…

Even NASA have trouble prising raw data out of friend researchers

January 24, 2014 1 comment


Image couresty NASA, discovery of a new class of star

This is a tale where I am going to maintain cloaking embarressment over wasting the time of others.

The original version of this story, which I have read, is not as kind, Rather annoyed folks were writing.

In many cases raw data is not available or only pseudo raw, ie. cooked in various unspecified or even unknown ways, when raw means what it says, original instrumentation data, with ancillary full information. Too often claims of raw are plain nonsense. This has wasted my time, prevented proper data processing, etc. a lot of tales I could recount.

Read more…

Fractional dataset delay (subsample resolution) in a spreadsheet

November 12, 2013 3 comments

Figure 1


Working code is provided[1] for copying and use, no macros.

Fractional delay means one timeseries can be delayed or advanced in time relative to another by any amount including any fraction of one sample time. This is achieved by a short digital filter (5 taps) which is “designed” by the spreadsheet to user demand.

A demonstration of usage on real data is the next DaedalEarth article.  Link to demonstration.

Read more…

Categories: filtering, software

Combining many PDF files into one

November 4, 2013 Leave a comment


Combining (or merging or whatever you call it) two or more PDF files into a single output PDF is very easy to do without needing to pay for anything provided you can do simple typing.

This contradicts various web advice sites, how-to and so on where surprise surprise the solution is buy this or that.

Unix users, BSD, Linux, OSX probably won’t need telling but the following with slight changes works there too.

I often use Method 2 but for this is horses for courses, why we have a brain.

I’ve written this without assuming the reader is much of an expert, might be talking down.

Read more…

Categories: software

Colour, artists, technicians, Isaac Newton onwards.

May 20, 2012 Leave a comment

The website Dimensions of Colour by David Briggs is based on material taught at the Julian Ashton Art School, Sydney, Australia, made available for all of us to learn.

FOREWORD: COLOUR THEORY MADE DIFFICULT yet paraphrasing a gentleman but no more than necessary. Artists from all fields who use colour, oils, pastels, room decore, computer jockeys, ought to know more. If David is right, implying it has been criticised as too difficult and too simple, must be about right.

I didn’t know how fundamental Newton has been, inventing the concept of the colour wheel, is history here too.

I came across the site during investigation of colour space after hitting trouble in implementing HSL/HSI/HSV Uncle Tom and finding things are a mess. Change of tack, going to try proper matrix operations instead.

Best of luck.

Click the image or here. (both open in new window)

Categories: education, History, software

Graphline, extract data from a plot

March 30, 2012 Leave a comment


A little while ago I needed to extract data from a plot but no tool I could find actually worked on awkward data, quite a common problem. Read more…

Categories: Datasets, software