Visually discernable error in energy value of Coal / wood

[johnkellas]

Smaller tree than pile of wood to power same number of lightbulbs.

[christopherreay]

where?

[christopherreay]

that doesn't even make sense

[christopherreay]

pics or it didn't happen

[johnkellas]

took video -- git doesnt allow upload, gif converter pissed me off. fair enough github dont want to host videos. took images again: here they are:

[christopherreay]

so... coal bank density 1346, bulk density 833 (we have 833) 24 to 35 MJ/Kg (we have 27)

wood we have a density of 500 and 19MJ/Kg

Oh, I see. the numbers are right. But the picture is wrong. Well thats no surprise

I think I remember saying that the trees were half the size they are meant to be a few times a few years ago

or double or whatever

[christopherreay]

Just a simple matter of altering the database live, lol

request.root['modelClasses']['Wood']['svgDisplayDefs']['svgDefinitions'][('volume',)]['svgDisplayDefByValue']['toReturn = True']['height']='\nif svgQuantiseValue < 1.0:\n toReturn = (0.7853 svgQuantiseValue 2) / 0.0624921884 / math.pi\nelse:\n toReturn = 8\n'

check it out on dev for me, and Ill roll it out into the production DB

Im a bit tired.

That one line, btw, will update all the trees. I could make them a bit easier to find. I never thought about that. There is already a dictionary called "representations" (this one is representations['Trees']) but I never explicitly stored it with its own key in the db. I can add that. @ has all of this stuff just built into the basic principles

[christopherreay]

Ive checked the picture. The tree is indeed now twice the size, which is a wonderful proof of concept of updating the live DB.

we need to put together a decent equation for the size of the tree when there is <= 1 tree. Cos it still looks wrong

'\nif svgQuantiseValue < 1.0:\n toReturn = (0.7853 svgQuantiseValue 2) / 0.0624921884 / math.pi\nelse:\n toReturn = 8\n'

==

if svgQuantiseValue < 1.0: #i.e. there is less than one tree
  #hmm thinking about this now, surely it should just be 8 * svgQuantiseValue. Obvs. This is not something I considered. This is the equation for a golden cuboid. This should work lovely
  toReturn = (0.7853 * svgQuantiseValue * 2) / 0.0624921884 / math.pi
else:
  toReturn = 8

[christopherreay]

Ahem. so it did work, in memory, but wasnt persisted to the database. Obvs since the ['height'] string isnt a persistent object. So we need to mark the ['toReturn = True'] object as _p_changed=True

Oh well, not quite. But nearly. Ill set it to that value in ram, and work out the persistence nonsense tomorrow

Bibliography:

• http://www.zodb.org/en/latest/guide/writing-persistent-objects.html

[christopherreay]

well. Its certainly bigger now. Lols (was / rather than *, so size of eifel tower)

[christopherreay]

So the issue now is that the svgQuantise equation for the tree needs to be better. Need to work out How much wood is actually in an 8 meter tall tree trunk of a tree like that. and then ... lovely jubly

[johnkellas]

Here is https://www.forestry.gov.uk/pdf/TimberVolumeCalculator.pdf/$FILE/TimberVolumeCalculator.pdf Assumptions - particularly the estimated trunk width - will need to be made

[christopherreay]

look at the picture? take a guess?

On May 31, 2017 08:47, "johnkellas" notifications@github.com wrote:

Here is https://www.forestry.gov.uk/pdf/TimberVolumeCalculator.pdf/$FILE/ TimberVolumeCalculator.pdf Assumptions - particularly the estimated trunk width - will need to be made

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/christopherreay/thisEqualsThat_frontEnd/issues/121#issuecomment-305112472, or mute the thread https://github.com/notifications/unsubscribe-auth/AAOnvqoFoP82fJil8JzHE92TYnETGXDXks5r_Rr2gaJpZM4NquYG .

[johnkellas]

The tree has been 4m to date. If it is 8m then a 60cm girth seem appropriate. I am pretty sure that the 4m tree was modelled on a one tonne carbon model - corresponding to the forestry volume sheet linked to above - if the 4m tree had a 60cm girth.

So we are talking about same girth, double the height. Odd in a way, but fine I reckon

[christopherreay]

the tree in that picture is much taller than 4m

On May 31, 2017 09:34, "johnkellas" notifications@github.com wrote:

The tree has been 4m to date. If it is 8m then a 60cm girth seem appropriate. I am pretty sure that the 4m tree was modelled on a one tonne carbon model

• corresponding to the forestry volume sheet linked to above - if the 4m tree had a 60cm girth.

So we are talking about same girth, double the height. Odd in a way, but fine I reckon

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/christopherreay/thisEqualsThat_frontEnd/issues/121#issuecomment-305123238, or mute the thread https://github.com/notifications/unsubscribe-auth/AAOnvuPF16_dBSJNkYcKV9KNQLFgzPdgks5r_SX9gaJpZM4NquYG .

[johnkellas]

You are right

[johnkellas]

60 cm girth for 8m tree seems ok to me

[christopherreay]

ok I shall plug the numbers when I'm back from the gym

On May 31, 2017 09:44, "johnkellas" notifications@github.com wrote:

60 cm girth for 8m tree seems ok to me

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[christopherreay]

So ive got the tech down. But wtf does this mean? What should the numbers be?

https://visual.tools/infogram/fe31cddaad8c4c95b55b06bb756c73c2