I'm having some trouble with the dissolve tool in arcgis. I have a stream network that has some streams made up of a number of little segment that I would like to transform so that all the stream portions that are connected to each other appear as one entity, a longer stream.

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Here is a zoom with selected portions of streams in blue to illustrate my problem

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I'd like to have all these portions of the stream (blue and black) as one entity but I also need to keep the informations such as length (long_m) for the whole stream once they are merged together. I assume that the statistics field with the statistic type SUM can make this work.

Here is what my attribute table looks like.

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As I said I have tried the dissolve tool but haven't been able to find a way to get the streams like I wanted. Ideally each small part composing the stream would be added to each other considered as one entity and the length of each portions would be added to form one stream with one longer length.

here is how I set up my dissolve, I've also tried other to check unsplit lines but it didn't work.

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  • Can you add a pic showing us how you are setting up your dissolve? Dissolve with the sum field should work. [link] desktop.arcgis.com/en/arcmap/10.5/tools/data-management-toolbox/… – Mary Johnson Jun 16 '18 at 12:22
  • yes absolutely ! – tony-bof Jun 18 '18 at 13:24
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    Do you need to separate streams by their tributaries? Perhaps you could dissolve on the stream name? I would try unchecking the multipart features option especially if you do a general dissolve. You can always recalculate your lengths when you are done. – johns Jun 18 '18 at 14:39
  • I agree with John. Uncheck multi part feature and recalculate lengths after if you used the straight GIS length. – Mary Johnson Jun 20 '18 at 12:33

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