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ST_Intersects Function- is there a bug?

BeginnerMindset
8 - Asteroid

Apologies in advance if this is the wrong forum for this.  When solving Challenge 137 I noticed something strange about ST_Intersects.  I created two fields after ST_Intersects didn't give me what I expected:

 

ST_Intersects([LineToSplicePoint],[WaterBoundary])

 

ST_Intersection([LineToSplicePoint],[WaterBoundary])

 

I expected the first one to give False values when the second one gave Nulls, to show that the two shape objects did not intersect.  However this wasn't the case.

 

Perhaps someone could explain what I did wrong.  And if I didn't do anything wrong then perhaps the developers could look into it?

Please let me know if there is a better forum for this type of question.

 

Thanks

6 REPLIES 6
Qiu
17 - Castor

@BeginnerMindset 

The input of the formula is two points. which will not intersect anyway.

We need to create Sptial objects in order for the formula to work. below is my old one.

ST_Intersects

ST_Intersects(object1, object2...): Returns True if the spatial objects intersect (Boolean value)



Qiu_0-1615031820881.png

 

BeginnerMindset
8 - Asteroid

Thanks for trying @Qiu but this can't be the answer. The input in the formula is not two points.

 

I have put in a Line and a Polygon, not two points. The formula detects the intersection in some cases, but it is the inconsistency with the ST_Intersection function that is the issue.  False results should line up with the Null results below, which they sometimes do but not every time.

 

See screenshots below

 

BeginnerMindset_0-1615034143386.png

 

BeginnerMindset_1-1615034286825.png

 

SeanAdams
17 - Castor
17 - Castor

This seems like a question for the legendary @Hollingsworth or @MarqueeCrew  who both know spatial backwards.

MarqueeCrew
19 - Altair
19 - Altair

@SeanAdams ,

 

.lortnoc-fles ym rof ssendoog knahT .sdrawkcab noitseuq siht rewsna ot em rof saw ti gnitpmet woh hO

 

Take a look at this picture!

capture.png

 

The data preview for [CrossWater - String] shows a value of 0, yet it returns 1 in the output.

The data preview for [CrossWater - Bool] shows a value of False, yet it returns True in the output.

Both data preview and output show Null for the actual Intersection.

 

This looks like a bug to me.

 

Cheers,

 

Mark

 

@echuong1 

 

Alteryx ACE & Top Community Contributor

Chaos reigns within. Repent, reflect and reboot. Order shall return.
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BeginnerMindset
8 - Asteroid

@MarqueeCrew @SeanAdams  Thanks for confirming it's a bug. Glad it's not just me going mad!

 

Cheers

James

MarqueeCrew
19 - Altair
19 - Altair

@BeginnerMindset ,

 

 just a reminder that those two conditions are not mutually exclusive of each other. 

cheers,

 

 mark

Alteryx ACE & Top Community Contributor

Chaos reigns within. Repent, reflect and reboot. Order shall return.
Please Subscribe to my youTube channel.
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