Skip to content

Latest commit

 

History

History
71 lines (46 loc) · 3.78 KB

building-the-webtool.md

File metadata and controls

71 lines (46 loc) · 3.78 KB
Raw

Putting the calculator online

One of the unusual things about the 2050 calculator is that you can use it over the internet. This section describes why we did this, and what is needed for you to do it. Detailed instructions are in an appendix.

Why build a web interface?

  1. More people will use the model.
  2. The model can be used in interactive presentations and debates.
  3. The model will run faster.
  4. It will be easier to share results.

What sort of web interface should you build?

Choice around:

  1. number of choices you present
  2. range of consequences you present
  3. balance between presenting numbers, and presenting impression

We went for two different web interfaces:

  1. One that sticks very closely to the Excel spreadsheet, presenting 40 or so choices, many consequences, using number and being quite dry. Target is people who are already interested in the subject. (In the UK, we call this the webtool).
  2. One that has only 14 chocies, displays only a few consequences, mainly presents pretty graphics. Target is people who are not initially interested. (In the UK we call this my2050).

What do you need to build one?

Skills required:

  1. Some Javascript
  2. Some ability with 'the command line'
  3. Ideally, some ruby, but not too important

Level required:

  1. Someone who is enthusiastic about programming and has done some before (perhaps as part of an engineering or science degree) is sufficient.

Time require:

  1. If it is very similar to the UK version, then it can be ready in a couple of weeks of amateur time.
  2. If it is different to the UK version, then may take some months.

What steps should you take?

  1. Decide what consequences are important to your users
  2. Decide what choices are important to your users
  3. Get the UK version working on your system
  4. Replace the UK model with your model
  5. Adapt the first sreen of the online tool to fit your needs
  6. Gradually introduce other charts and views

When should you start?

Start as soon as you have a more-or-less complete spreadsheet. The spreadsheet doesn't have to be finished: it is ok for the numbers and formulae to change. However, it is best if the structure of the spreadsheet (e.g., number of years, numebr of sectors, output tables wired up) is more-or-less finalised.

Things you might be tempted to do (but perhaps shouldn't)

You may be tempted to:

  1. Try and drive the Excel spreadsheet directly, using Microsoft interfaces. We've found that this is too slow and too unreliable for a good user experience.
  2. Put more than 40 levers on the online interface. We found that this means you can't get a good overview of what it going on, and takes too long for people to use.

Reducing the number of choices you present to the user

You will probably want to have a version of the web interface for experts, that pretty much exactly replicates the Excel, but in a quicker, easier to use form. You may also want to have a simpler web interface for non-experts (in the UK we call this my2050). To make it simpler, one of the things that you may need to do is to reduce the number of choices you present to the user.

This involves going through each choice in the Excel and deciding whether to:

A. Keep the choice in the simple interface (e.g., Nuclear power was kept in the UK my2050 version) B. Not include the choice, but instead leave it set at one level (e.g., Geosequestration is always set at level 1 in the UK my2050 version) C. Combine the choice with another choice (e.g., The Heating Choice lever in the UK my2050 version actually controls 4 levers in the Excel spreadsheet at the same time).

Resources

  1. The source code to the UK interface is available at http://github.com/decc/twenty-fifty.