Question

how to dissolve line segments into long line?

judy_fme
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I need to dissolve line segments into long line base on some attributes. I tried LineCombiner and it doesn't work, still same segments in the result.

13 replies

david_r
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Userlevel 4

Could it be that there are tiny imprecisions in the start/end vertices of the line segments? Perhaps try inserting a Snapper with end point snapping just before the LineCombiner. If that doesn't work, check if the LineCombiner works without the Group By-attributes -- if that's the case, then something is wrong with the Group By-attributes.

judy_fme
Badge +1

I used ESRI ArcMap tool box, a tool called dissolve, that can do the work without any issue. I don't specify snapping. just dissolve line segments base on same attribute values. it can be multiline while they are not adjacent. I am wondering if there is any transformer dedicated for dissolving line segments as same as ESRI's one?

hkingsbury
Rank
Userlevel 5
Badge +29

I used ESRI ArcMap tool box, a tool called dissolve, that can do the work without any issue. I don't specify snapping. just dissolve line segments base on same attribute values. it can be multiline while they are not adjacent. I am wondering if there is any transformer dedicated for dissolving line segments as same as ESRI's one?

Aggregator might suffice. It will create aggregates (groups) of lines

Check out the Abley FME Firesides on Youtube: https://www.youtube.com/@ableyltd
david_r
Rank
Userlevel 4

I used ESRI ArcMap tool box, a tool called dissolve, that can do the work without any issue. I don't specify snapping. just dissolve line segments base on same attribute values. it can be multiline while they are not adjacent. I am wondering if there is any transformer dedicated for dissolving line segments as same as ESRI's one?

The ArcGIS toolboxes actually apply a tiny amount of "snapping" to all the features, according to the tolerance settings of the feature class. FME does not, which is why it may sometimes be necessary to use a Snapper with a very small tolerance to make sure all the vertices line up perfectly.

judy_fme
Badge +1

Aggregator might suffice. It will create aggregates (groups) of lines

thanks for the help. Aggregator is not for this dissolving purpose I guess. it doesn't ask attribute based on.

judy_fme
Badge +1

The ArcGIS toolboxes actually apply a tiny amount of "snapping" to all the features, according to the tolerance settings of the feature class. FME does not, which is why it may sometimes be necessary to use a Snapper with a very small tolerance to make sure all the vertices line up perfectly.

I have to use ArcGIS toolboxes. I thought FME has everything ArcGIS toolboxes provided.😏

judy_fme
Badge +1

I am new for FME actually. I have FME case C657637 generated. but is any support to open the case?

hkingsbury
Rank
Userlevel 5
Badge +29

Aggregator might suffice. It will create aggregates (groups) of lines

Thats where you'd use group by. Populating the Group By field will only aggregate features that share a common value in the specified attribute(s)

 

https://docs.safe.com/fme/html/FME_Desktop_Documentation/FME_Transformers/Group_Based_Transformers.htm

Check out the Abley FME Firesides on Youtube: https://www.youtube.com/@ableyltd
hkingsbury
Rank
Userlevel 5
Badge +29

The ArcGIS toolboxes actually apply a tiny amount of "snapping" to all the features, according to the tolerance settings of the feature class. FME does not, which is why it may sometimes be necessary to use a Snapper with a very small tolerance to make sure all the vertices line up perfectly.

The thing to note about comparing FME and ArcGIS is that on the surface, it looks like it is a one to one relationship (i.e one tool in FME does what one tool in AG does) but it isn't. Another thing to note is that FME operations on a feature by feature level (row by row) where as AG generally operates on a feature class by feature class (table by by table) basis. Two very different ways of processing data

Check out the Abley FME Firesides on Youtube: https://www.youtube.com/@ableyltd
caracadrian
Rank
Badge +20

Can you provide some sample data?

Generally what @david_r​ said about snapping should work. Maybe there is something you are missing.

david_r
Rank
Userlevel 4

I am new for FME actually. I have FME case C657637 generated. but is any support to open the case?

You can check the progress of your support cases here: https://community.safe.com/s/case/Case/Default

david_r
Rank
Userlevel 4

The ArcGIS toolboxes actually apply a tiny amount of "snapping" to all the features, according to the tolerance settings of the feature class. FME does not, which is why it may sometimes be necessary to use a Snapper with a very small tolerance to make sure all the vertices line up perfectly.

Apples and oranges, as @hkingsbury​ is also alluding to. FME and ArcGIS are complementary, not 100% overlapping (what would be the use of that).

judy_fme
Badge +1

The ArcGIS toolboxes actually apply a tiny amount of "snapping" to all the features, according to the tolerance settings of the feature class. FME does not, which is why it may sometimes be necessary to use a Snapper with a very small tolerance to make sure all the vertices line up perfectly.

agree, "complementary" is good explanation.

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