It's About: Challenge 84 ,Gap on every special object join

subhajits11

Hello Trixians,

Thanks you for wonderful challenge which i was trying to achieve and came with some gaps generating for special lines,If Anyone could see and help me out with my understanding ,I am posing it in Alteryx Community,Thanks In advance.

Challenge Link: https://community.alteryx.com/t5/Weekly-Challenge/Challenge-84-Map-Hurricane-Harvey-s-Storm-Evolution/td-p/79533

Here I am elaborating my understanding.
-- In the data set we are getting special Objects (centroids) or lat/long points,Intensity for every points and  the type of the storm.

Now, the requirement is to combine those centroids into special line  by groping avg intensity ,its sounds very simple but while trying to make lines using special poily build tool its combining centroid points and making special line object, for the 'Group ID' 4 its not able to create any line as Group id 4 available with one single point ,which returns Null.

So,As per my understanding this GAP in the visualization should show only only for group 3-5(for null output in Group id 4) but in visualization for  every group its creating "Gap".Example:  1-2(Gap),5-6(GAP) .

Now,Though the Solution is given in the above mentioned link but I am trying to understand mentioned above, If any help! 

Thanks!

challenge_84_start_file.yxzp

CharlieS

Hi @subhajits11 

The key to generating the continuous path you see in the solution is that the they connect the last point of each "Group By ID" to the first point of the next ID value. When you Group By the ID then combine the SpatialObjs, you're not taking into consideration the first point in the next series to connect the lines. In the case of ID 4 (which only has 1 point), the line is created by the only ID 4 point connected to the first ID 5 point. 

Alternative to the batch macro of their attached solution, since these points are in sequential order, I think it makes sense to use a Multi-Row Formula tool to create the lines. I use the ST_CreateLine( spatial function in an expression that looks like this (using the point from this row and creating a line to the point from the next row): 

ST_CreateLine([SpatialObj],[Row+1:SpatialObj])

I've added a couple tools to your solution to show this in action. 

20200622-Challenge_84_Alternative.yxmd