{ "id": 6681, "title": "Frankly, I cannot tell the difference between classes with my naked eyes", "url": "/competitions/galaxy-zoo-the-galaxy-challenge/discussion/6681", "author_name": "", "post_date": "2013-12-26T01:55:37.700Z", "votes": null, "comment_count": 4, "views": 2185, "content": "

looking at class 2.2 and class 3.1 and many other classes, what's the difference?

", "messages": [ { "id": "36647", "postDate": "12/26/2013 01:55:37", "content": "

looking at class 2.2 and class 3.1 and many other classes, what's the difference?

", "rawMarkdown": "", "votes": null }, { "id": "36650", "postDate": "12/26/2013 05:08:39", "content": "

The differences get more subtle the further down the tree one gets. For 2.2 and 3.1 specifically, class 2.2 refers to feature/disk galaxies that aren't edge on. The two classes of 3.1 and 3.2 divide these galaxies from 2.2 according to whether they do or do not (respectively) have a bar. A galactic bar is a long, linear feature going through the center of the galaxy.

\n

Here are examples of the differences you're looking for:

\n

Barred galaxy (3.1):

\n

\"Barred

\n

Unbarred galaxy (3.2):

\n

\"Unbarred

", "rawMarkdown": "", "votes": null }, { "id": "36664", "postDate": "12/26/2013 15:58:23", "content": "

[quote=Kyle Willett;36650]

\n

The differences get more subtle the further down the tree one gets. For 2.2 and 3.1 specifically, class 2.2 refers to feature/disk galaxies that aren't edge on. The two classes of 3.1 and 3.2 divide these galaxies from 2.2 according to whether they do or do not (respectively) have a bar. A galactic bar is a long, linear feature going through the center of the galaxy.

\n

[/quote]

\n

 

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Thanks for the clarification.  I should get myself more familiar with the terminology.

\n

One more question, one the data page it says:

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    "The sum of Class 1.1-1.3 and of Class 6.1-6.2 for each galaxy will always sum to 1.0"

\n

However this is not what I see in the solutions_training.csv:

\n

$ awk -F',' 'BEGIN {OFS="\\t"} {print $9,$10}' solutions_training.csv | head
Class4.1          Class4.2
0.96915           0
0                       0.092637622
0                       0.275176247
0.566836809  0.058381649
0                       0.533600381
0                       0.034964683
0                       0.183850932
0.941               0
0                       0.303717

\n

The two columns of Class4 do not sum to one. I checked all question 1-6 only solutions to question 1 and question 6 sum up to 1.0.

\n

did I do anything wrong?

", "rawMarkdown": "", "votes": null }, { "id": "36668", "postDate": "12/26/2013 16:43:48", "content": "

The columns of the class 4 should not necessarily sum to one. The questions are concatenated and must sum to the value of the corresponding upper level. Check this point (weighting the responses and decision tree). 

\n

http://www.kaggle.com/c/galaxy-zoo-the-galaxy-challenge/details/the-galaxy-zoo-decision-tree

", "rawMarkdown": "", "votes": null }, { "id": "36670", "postDate": "12/26/2013 17:19:18", "content": "

[quote=Rafael Hernández Murcia;36668]

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The columns of the class 4 should not necessarily sum to one. The questions are concatenated and must sum to the value of the corresponding upper level. Check this point (weighting the responses and decision tree). 

\n

http://www.kaggle.com/c/galaxy-zoo-the-galaxy-challenge/details/the-galaxy-zoo-decision-tree

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[/quote]

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got it, thanks

", "rawMarkdown": "", "votes": null } ], "comments": [ { "id": 36650, "author_name": "willettk", "author_url": "", "post_date": "12/26/2013 05:08:39", "content": "

The differences get more subtle the further down the tree one gets. For 2.2 and 3.1 specifically, class 2.2 refers to feature/disk galaxies that aren't edge on. The two classes of 3.1 and 3.2 divide these galaxies from 2.2 according to whether they do or do not (respectively) have a bar. A galactic bar is a long, linear feature going through the center of the galaxy.

\n

Here are examples of the differences you're looking for:

\n

Barred galaxy (3.1):

\n

\"Barred

\n

Unbarred galaxy (3.2):

\n

\"Unbarred

", "votes": null, "replies": [] }, { "id": 36664, "author_name": "yzhao0527", "author_url": "", "post_date": "12/26/2013 15:58:23", "content": "

[quote=Kyle Willett;36650]

\n

The differences get more subtle the further down the tree one gets. For 2.2 and 3.1 specifically, class 2.2 refers to feature/disk galaxies that aren't edge on. The two classes of 3.1 and 3.2 divide these galaxies from 2.2 according to whether they do or do not (respectively) have a bar. A galactic bar is a long, linear feature going through the center of the galaxy.

\n

[/quote]

\n

 

\n

Thanks for the clarification.  I should get myself more familiar with the terminology.

\n

One more question, one the data page it says:

\n

    "The sum of Class 1.1-1.3 and of Class 6.1-6.2 for each galaxy will always sum to 1.0"

\n

However this is not what I see in the solutions_training.csv:

\n

$ awk -F',' 'BEGIN {OFS="\\t"} {print $9,$10}' solutions_training.csv | head
Class4.1          Class4.2
0.96915           0
0                       0.092637622
0                       0.275176247
0.566836809  0.058381649
0                       0.533600381
0                       0.034964683
0                       0.183850932
0.941               0
0                       0.303717

\n

The two columns of Class4 do not sum to one. I checked all question 1-6 only solutions to question 1 and question 6 sum up to 1.0.

\n

did I do anything wrong?

", "votes": null, "replies": [] }, { "id": 36668, "author_name": "rafahernandez", "author_url": "", "post_date": "12/26/2013 16:43:48", "content": "

The columns of the class 4 should not necessarily sum to one. The questions are concatenated and must sum to the value of the corresponding upper level. Check this point (weighting the responses and decision tree). 

\n

http://www.kaggle.com/c/galaxy-zoo-the-galaxy-challenge/details/the-galaxy-zoo-decision-tree

", "votes": null, "replies": [] }, { "id": 36670, "author_name": "yzhao0527", "author_url": "", "post_date": "12/26/2013 17:19:18", "content": "

[quote=Rafael Hernández Murcia;36668]

\n

The columns of the class 4 should not necessarily sum to one. The questions are concatenated and must sum to the value of the corresponding upper level. Check this point (weighting the responses and decision tree). 

\n

http://www.kaggle.com/c/galaxy-zoo-the-galaxy-challenge/details/the-galaxy-zoo-decision-tree

\n

[/quote]

\n

 

\n

got it, thanks

", "votes": null, "replies": [] } ], "raw_markdown_by_id": { "36647": "", "36650": "", "36664": "", "36668": "", "36670": "" }, "source": "meta" }