Robin's Blog

Previously Unpublicised Code: RTWIDL

When looking through my profile on Github recently, I realised that I had over fifty repositories – and a number of these weren’t really used much by me anymore, but probably contained useful code that no-one really knows about! So, I’m going to write a series of posts giving brief descriptions of the code and what it does, and point people to the Github repository and any documentation (if available). I’m also going make sure that I take this opportunity to ensure that every repository that I publicise has a README file and a LICENSE file.

So, let’s get going with the first repository, which is RTWIDL: a set of useful functions for the IDL programming language. It’s slightly incorrect to call this “unpublicised” code as there has been a page on my website for a while, but it isn’t described in much detail there.

These functions were written during my Summer Bursary at the University of Southampton, and are mainly focused around loading data from file formats that aren’t supported natively by IDL. Specifically, I have written functions to load data from the OceanOptics SpectraSuite software (used to record spectra from instruments like the USB2000), Delta-T logger output files, and NEODC Ames format files. This latter format is interesting – it’s a modification of the NASA Ames file format, so that it can store datetime information as the independent variable. Unfortunately, due to this change none of the ‘standard’ functions for reading NASA Ames format data in IDL will work with this data. Quite a lot of data is available in this format, as for a number of years it was the format of choice of the National Earth Observation Data Centre in the UK (see their documentation on the format). Each of these three functions has detailed documentation, in PDF format, available here.

As well as these functions, there are also a few utility functions for checking whether ENVI is running, loading files into ENVI without ENVI ‘taking over’ the IDL variable, and displaying images with default min-max scaling. These aren’t documented so well, but should be fairly self-explanatory.

RTWIDL is released under the BSDĀ license, and is available atĀ https://github.com/robintw/RTWIDL


Categorised as: Academic, Computing, IDL, Previously Unpublicised Code, Programming, Remote Sensing


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