Matt McLean

Tip of the Week #58 - Average Points vs Merge Points Command

Blog Post created by Matt McLean on Sep 29, 2018

Hello folks and welcome here to yet another TBC Tip of the Week! Happy Friday, Happy Monday, or Happy whichever day you happen to stumble upon this tip!

 

Today we will be taking a look at two similar but different commands under the CAD Ribbon, Average Points and Merge Points. Each has distinct functionality that is useful in situations with different intended outcomes.

 

The Average Points command computes the simple mean of all points selected — the average horizontal and vertical positions — and creates a new point with lines drawn from each of the points involved in the average. Below, we have three total station observations to the same point, and we want to take the average of these points to use as our observed point.

 

In the drop down for each point under Status, points can be enabled or disabled to easily filter outliers.

When it is computed:

 

The resulting point 100 is an arithmetic 3D mean of points 16, 17, and 18.

 

Now onto the Merge Points command! This one has a little more to it and is more flexible than the Average Points command so long as the points are all sideshots (not station setups). In the image below, under Filter Points by ID, are two options. Given the points are the same coordinate quality, identical will merge all points with identical ID’s. For example, if there are 4 points with ID ‘A’, and 3 points with ID ‘B’, these will be merged into two separate points A and B. Ignored will merge all points regardless of ID.

 

Filter Points by Distance will, you guessed it, filter points based on the distance of each selected point to the position of the specified final point.

 

When points being merged have different qualities ie. Control vs Survey vs Mapping vs Unknown, points can be merged with points of different qualities, however only a point of the highest quality in the selection will be used for the final point. Below, I have added a point of unknown quality using the Create Point command. TBC will merge lower quality points with higher quality, but will not merge higher quality points with lower quality. Under Selected Points, you may select which point will be the final position, and which points will be merged by checking the Included boxes. The distance each point will be moved to be merged is dynamically updated under Distance. To change the point ID of the merged point, you can enter it under Point ID.

 

This will merge all 4 points with point 16, and will name the resulting point 16.

 

There you have it! Depending on the desired outcome of your survey and your knowledge of how it was conducted, you can merge or average points to best suit your needs.

 

TBC - From Field to Finish with Confidence.

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