Question

Anchored Snapper - Use only the vertices of the anchor.

  • 4 February 2022
  • 5 replies
  • 4 views

Badge

I am trying to utilize the Anchored Snapper to snap the edge of a zoning area to the underlying parcel boundaries. The tool visually works great; however, it is utilizing the vertices of both features resulting in overlaps and slivers that are later detected in our workflow. Is there a means to have the Anchored Snapper only utilize the vertexes of the anchor? Is there a better tool option that will not change the parcel feature?


5 replies

Userlevel 2
Badge +17

Hi @lance​,

The difference between the Snapper and the AnchoredSnapper is that the AnchoredSnapper should not change the vertex locations of the Anchor features. If you are sending the parcel boundaries to the Anchor port, and you find that the parcel boundaries are changing, please contact FME Support so that we can resolve this problem.

Badge

Hi @lance​,

The difference between the Snapper and the AnchoredSnapper is that the AnchoredSnapper should not change the vertex locations of the Anchor features. If you are sending the parcel boundaries to the Anchor port, and you find that the parcel boundaries are changing, please contact FME Support so that we can resolve this problem.

No, That is not what I was asking. AnchoredSnapper works great. I am asking if it is possible only to use the vertices in the anchor and eliminate any extra vertices in the feature being snaped. Adding missing vertices to the feature is not an issue if a corresponding node is in the underlying component. Some users have just been relying on snapping the edge rather than tracing features during data collection. For example, below are a couple of screenshots. The first is the vertices of the parcel layer, and the second is the zoning layer after using the AnchoredSnapper. Not the unneeded vertices in the zoning layer.

Anchor LayerSnapped Layer - Note extra vertices

Userlevel 2
Badge +17

No, That is not what I was asking. AnchoredSnapper works great. I am asking if it is possible only to use the vertices in the anchor and eliminate any extra vertices in the feature being snaped. Adding missing vertices to the feature is not an issue if a corresponding node is in the underlying component. Some users have just been relying on snapping the edge rather than tracing features during data collection. For example, below are a couple of screenshots. The first is the vertices of the parcel layer, and the second is the zoning layer after using the AnchoredSnapper. Not the unneeded vertices in the zoning layer.

Anchor LayerSnapped Layer - Note extra vertices

The screenshots you have attached don't appear. Could you please post them again?

Badge

No, That is not what I was asking. AnchoredSnapper works great. I am asking if it is possible only to use the vertices in the anchor and eliminate any extra vertices in the feature being snaped. Adding missing vertices to the feature is not an issue if a corresponding node is in the underlying component. Some users have just been relying on snapping the edge rather than tracing features during data collection. For example, below are a couple of screenshots. The first is the vertices of the parcel layer, and the second is the zoning layer after using the AnchoredSnapper. Not the unneeded vertices in the zoning layer.

Anchor LayerSnapped Layer - Note extra vertices

Apologies, I did not realize screenshots would not post from an email reply. I added the images this morning.

 

Additional note, I understand that snapper is working perfectly. The coincident zoning polygons are being snaped to the anchor parcel as the tools as designed. However, I am ending up with the vertices for all the features. I did use the generalize tool both before and after to eliminate most of the extra vertices but there is no control as to which vertices are removed. We are sometimes ending up with slivers where the vertices do not align.

 

Userlevel 2
Badge +17

No, That is not what I was asking. AnchoredSnapper works great. I am asking if it is possible only to use the vertices in the anchor and eliminate any extra vertices in the feature being snaped. Adding missing vertices to the feature is not an issue if a corresponding node is in the underlying component. Some users have just been relying on snapping the edge rather than tracing features during data collection. For example, below are a couple of screenshots. The first is the vertices of the parcel layer, and the second is the zoning layer after using the AnchoredSnapper. Not the unneeded vertices in the zoning layer.

Anchor LayerSnapped Layer - Note extra vertices

I guess that some segments of the snapped line form spikes overlapping on the line.

If my guessing is correct, you can use SpikeRemover (Maximum Spike Angle: very small value, e.g. 1e-8; Remove Spikes Iteratively: Yes) to remove those spikes and then use Generalizer to remove remained extra vertices.

Reply