I am tracing a building from Bing aerial image. The building is square but has some irregular projections. I first trace the square portion (as an area) so I can use the Q shortcut to make it square. Then I trace the irregular part (as an area). There is, however, always a line where these two shapes are joined. Is there a way to 'delete' the joining line? Thank you

asked 24 Aug '13, 16:23

slover98's gravatar image

accept rate: 5%

edited 24 Aug '13, 20:19

aseerel4c26's gravatar image

aseerel4c26 ♦

Hi, in the editor Potlatch 2 just select a node and use scissor (disconnect) and both nodes and delete the way between them. Then read this one, can-two-ways-be-made-into-one-in-potlatch2. And add the tag "building" to the building outline.

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answered 24 Aug '13, 20:38

Hendrikklaas's gravatar image

accept rate: 6%

edited 24 Aug '13, 20:50

aseerel4c26's gravatar image

aseerel4c26 ♦

I realized that the chain is a very good tool and Ill use it, so far I improvised, but with a multi polygon it’s handsome.

(24 Aug '13, 22:10) Hendrikklaas

I often draw building the same way in Potlatch2. However, I rarely use the cut and rejoin approach. InsteadI save a batch of such buildings and then work through them in JOSM which has a tool to automatically combine (union) two or more polygons.

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answered 24 Aug '13, 22:56

SK53's gravatar image

SK53 ♦
accept rate: 20%

Thank you for the idea. JOSM is a little bit beyond my capability, I just do simple edits, like adding building, roads (service, parking aisles) lakes, shops etc. That's why I only use iD or Potlatch.

(25 Aug '13, 01:09) slover98

The square tool will give "L" or "C" or any shape square corners. So joining square bits may be unnecessary.

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answered 24 Aug '13, 20:48

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andy mackey
accept rate: 4%

edited 24 Aug '13, 20:50

I assume that the "irregular part" has no rectangular corners. And even if: drawing the base (square) building in a first step makes it really rectangular. This is not guaranteed if you draw it and make it rectangular in one step.

(24 Aug '13, 20:52) aseerel4c26 ♦

Hendrikklaas's answer is correct. but if the irregular bit does have square corners, as most buildings have, "joining MAY be unnecessary" and drawing the whole, then squaring it will save time over snipping and joining is S-L-O-W as you will know. Drawing building outlines is very time consuming. Any help in speeding up is worth knowing. (potlatch2)

(24 Aug '13, 21:26) andy mackey

Thank you all for the replies. The irregular part does not have square corners. It is a semi-circle or a partial ellipse.

(25 Aug '13, 01:07) slover98

Here is one of the buildings I need help with: http://www.openstreetmap.org/#map=17/38.81607/-77.64559

(25 Aug '13, 01:14) slover98

I just tried to fix it with the scissors in Potlatch. Hopefully, I did it OK. The map view still shows the old situation.

(25 Aug '13, 01:20) slover98

It is fixed!! THANK YOU ALL. Martin

(25 Aug '13, 01:21) slover98

If a building has non rectangular angles, act like a surveyor and take 2 nodes on the same line and trace the (help) line back to the building. Now the corner can be pinpointed or use even a second line to the same corner. This method works for every single edge of a building. Even consider to a take a spring rule for control purposes just a stretch and use JOSM. It has a simple scale in the left upper corner and several other handy tools for handling buildings.

(25 Aug '13, 09:37) Hendrikklaas
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question asked: 24 Aug '13, 16:23

question was seen: 5,910 times

last updated: 25 Aug '13, 09:37

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