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Given the following information, how does the program determine which side is the even-numbered side of the street?

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    In this example - because the Y coordinate of the From point is greater than the Y coordinate of the To point - the road therefore runs north to south - therefore the right hand side would be the west and the left hand side would be the east. Is this the kind of logic you are looking for?
    – dklassen
    Jan 27, 2014 at 19:38
  • @dklassen yes this is what i'm looking for, thank you
    – patrick
    Jan 27, 2014 at 19:40

3 Answers 3

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In this example - because the Y coordinate of the From point is greater than the Y coordinate of the To point - the road therefore runs north to south - therefore the right hand side would be the west and the left hand side would be the east. Is this the kind of logic you are looking for?

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It is based on what direction the line was digitized I believe. Therefore, if the line was digitized "FROM" - "TO" the "Right" side of the road would actually be the left side as we view it. If the the road was digitized the opposite way, then the right side would actually be on the right side as we view it.

Also, generally when building attribute data, those from/to fields are populated based on user input and therefore do not rely on vector geometry.

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This is based on the order of the vertices in your line. You need to consider yourself travelling from the first vertex to the last vertex, which tells you your left and your right. Programmatically, the left side is found if you turn anti-clockwise without crossing the line, and vice-versa.

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