Galaxy Zoo Starburst Talk

Tutorial on Filtering the Data According to Classification Results

  • trouille by trouille scientist, moderator, admin

    The classification results are in Tools and ready to be used.

    I've created a Dashboard to showcase a few ways you can filter the data according to our classification results. [Note: I've minimized the different tables so you could find them more easily. To open a table, just click on the circle in the upper left of the table itself. You might also need to stretch the table to a larger size by pulling on the bottom right corner of the table.]

    Table 3 shows the result of filtering to only show sources that don't have off-center bright clumps. Notice the syntax. It wouldn't work if I'd used lowercase 'no' or all uppercase 'NO'. The prompt has to match exactly to the response wording that you're filtering on. This is like in real programming -- computers can't make inferences on their own.

    Check out the other tables. For example, notice how in Table 9 you can apply two filters. In that case I filter both on redshift and sources that show no merger signatures

    I highly recommend sharing dashboards as you test out different filters. Do you notice any differences between a scatter plot for a subsample with one filter versus another filter?

    Posted

  • trouille by trouille scientist, moderator, admin

    Table 7 is interesting in that I used the 'not equal to' syntax. I wanted to choose objects that did show merger signatures, i.e., sources that were not given the 'Neither' response for 'Is the galaxy currently merging or is there any sign of tidal debris?'

    The syntax is

    filter .merging != 'Neither'

    Posted

  • trouille by trouille scientist, moderator, admin

    Check here for a discussion/glossary of what the full list of classification questions and possible responses were.

    Posted

  • jules by jules moderator

    This is beyond brilliant! Thanks Laura. 😃

    Posted

  • vrooje by vrooje moderator, scientist

    Quick note: I've also discovered that the filters don't seem to work if you use double-quotes to compare strings, i.e.,

    filter .merging != 'Neither'

    works, whereas

    filter .merging != "Neither"

    did not.

    (Just noting that in case anyone else comes across it...)

    Posted

  • lpspieler by lpspieler moderator

    Very helpful indeed! Are there also logical "or" connections between the filter criteria? Can "and"/"or" clauses be nested?

    think guess by now someone notices that I'm trying to find out how close to SQL this gets .../think

    Posted