Highlight untagged and unconnected nodes in a way

Question

While editing some cities I see a lot of unneeded/excessive nodes. For example, here:

Unneeded node

See that the street is straight and the left middle node is unneeded. I found question 8348 but I just can't select everything and simplify (it can remove valid nodes or just can't remove the node (caused by too high or too low max-error value)) nor I can select everything and straight them too.

While looking at the data with a lower zoom level it's also difficult to spot this small square in JOSM.

Another example:

Nodes

And the nodes that probably aren't needed:

Unneeded nodes 2

So my problem is: is it possible to highlight these kind of nodes in JOSM, please? (nodes that are part of a way, have no tags nor are connected to anything else (another ways, for example)). Something to display them with a big icon and/or color, like this:

Highleted

There is no problem that it's an ugly view but I need a quick way to view these possible spurious nodes (so I can then review them manually and remove if needed).

Accepted Answer

5

Answering my own question, I did create a MapCSS style:

way[highway] > node {
  symbol-size:10;
  symbol-shape: square;
  symbol-stroke-color: #00ffff;
  symbol-fill-color: blue;
}

node:connection, node:tagged {
  symbol-size:5;
  symbol-fill-color: #808080;
  symbol-stroke-color: #808080;
}

The first block will highlight with a blue square every node that is part of a way tagged with highway=* (even nodes that are tagged or connected to other ways, but they are handled after).

Second block will make nodes that are connected to other ways (node:connection) or nodes that have any tags (node:tagged) have a gray color and a smaller size (to stay less noticeable in JOSM).

This:

Original

Is now seen as this with the style:

Highlighted

Like aseerel4c26 suggested, missing features are:

Ignore initial/final nodes of the way
Ignore highways that are also part of a relation
Highlight only nodes within a certain angle threshold (so real curved ways could be ignored)

It is perfectly fitting my needs but any kind of suggestion/improvements are welcome.

permanent link

answered 22 May '13, 21:12

naoliv
600●7●10●19
accept rate: 37%

edited 25 May '13, 00:25

aseerel4c26 ♦
32.6k●18●248●554

1

Thanks for sharing!

And for those wondering what to do with the junk above... Use a text editor, paste the code, and save it as foo.css (or similar) anywhere. Then add the file path to JOSM in Edit/Preferences/Map Settings/Map Paint Styles.

I've used JOSM for years, but apparently there are still many things to find out. :)

(22 May '13, 21:39) gnurk

Very good, naoliv! For other who don't understand the CSS syntax that good, could you mention (please add it with the "edit" function) what the rule does? It is not as restrictive in highlighting as my suggested conditions (yes, those are not useful as they are, practically) are, right?

(22 May '13, 23:21) aseerel4c26 ♦

1

aseerel4c26, I did edit it like you suggested. And as you said, it doesn't implement all the rules from your other comment (but as it is now, it's perfectly fitting my needs). Thanks!

(24 May '13, 20:30) naoliv

1

Thanks again, ment ioned in the relevant (hopefully) wiki pages.

(25 May '13, 00:32) aseerel4c26 ♦

Answer 2

In your private data version you can remove (or do whatever you want with) these "unneeded" points. But, please, be careful doing similar changes to the OSM source data. There may be some, to us unknown, reasons for uploading these "unneeded"/redundant points by local editors. Besides, the cases you refer to are just a little fraction of the redundant node cases. The node redundancy comes from point replications, colinear (and almost colinear) neighbouring vector/line-segments, cases like ...A,B,C,B,C...C,D..., overlapping (or almost overlapping) ways/polylines in the same or different object classes and so on. The number of "unneeded" nodes in a Planet dump may easily exceed 10**8 (hundred million).

So, my suggestion is, do not worry about these "unneeded" points in the OSM source data. In raster mapping (rendered/pre-rasterized map images on servers) you will never see them. In vector mapping (rendering/rasterization on the clients, parametric data transmission) mappers will remove this redundancy anyway especially in mobile mapping (simply, it is too expensive to transmit them in cellular networks).

Highlight untagged and unconnected nodes in a way

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