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# Weekly Challenges

Solve the challenge, share your solution and summit the ranks of our Community!

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## Challenge #113: Interpolating Spatial Grid Values

Alteryx Alumni (Retired)

So many different solutions to last week's Challenge have been posted here!

This week's Challenge riffs off a process typically used in spatial analysis with raster inputs: interpolation.  In this Challenge, you are provided with two inputs: a polygon representing the island of Maui (hey, there's still snow in the forecast here in CO...can you blame me for picking a beachy location?) and a table of values representing the elevation measurements for 500 m x 500 m grid cells (much like a Digital Elevation Model).  However, some grid cells contain a value of 0.  We'll use some spatial tools to interpolate, or estimate, the values of the cells containing 0 from a "nearest neighborhood" or surrounding cell values.

First, build a 500 m x 500 m grid around the island of Maui.   Then, interpolate the missing value using the average of the known measurements from the surrounding cells, or "neighborhood".  Use a neighborhood of the 8 nearest surrounding cells in a unique cardinal direction (see example below; a neighborhood of a cell containing a 0 is outlined in blue. In this example, the new interpolated value of the center cell would be 61.5). Should a missing value be located on the edge, use only the nearest cells in a unique cardinal direction, even if 8 values are not used for the calculation.

Hint: Grid cell Grd37_68 is column 37, row 68. The Grid tool starts with column 0.

ACE Emeritus

Fun spatial exercise!

17 - Castor

I opted for a non-spatial technique.

EDIT: I added a spatial technique as well.

Spoiler

12 - Quasar

It's a good challenge when I start with a sheet of paper and pencil  to figure out the logic, before any tools get dropped onto a canvas.

Spoiler
7 - Meteor

Inactive User
Not applicable

12 - Quasar
Spoiler
Took me a while to wrap my head around this one! My way of solving it felt quite cumbersome, curious to see what better ways are out there.

8 - Asteroid

Here's my submission.

This was a great way for me to get more familiar with some of the Spatial tools, thanks!

Spoiler
8 - Asteroid

Slowly but surely learning how to use spatial tools

Spoiler
ACE Emeritus

My solution! Included both a spatial and a non-spatial solution :) Fun one!

Spoiler

Cheers,

NJ