Combine layers, merge and export flatten fields as csv

[2803media]

Hi I have two files:

communes.shp

[info] 
========================================
Layer:    communes
----------------------------------------
Type:     polygon
Records:  35,084
Bounds:   -178.181632,-85.05,168.133656,51.088756
CRS:      +proj=longlat +datum=WGS84
Source:   communes.shp

Attribute data
------------+---------------------------
 Field      | First value
------------+---------------------------
 code       | '01001'
 commune    | ''
 departemen | '01'
 epci       | '200069193'
 nom        | 'L'Abergement-Clémenciat'
 plm        | null
 region     | '84'
------------+---------------------------

And PLU_0.json

[info] 
==================================================
Layer:    PLU_0
--------------------------------------------------
Type:     polygon
Records:  10,000
Bounds:   -3.887635349735755,42.40435023605635,7.468601617593436,49.71331516396345
CRS:      +proj=longlat +datum=WGS84
Source:   PLU_0.json

Attribute data
------------+-------------------------------------
 Field      | First value
------------+-------------------------------------
 bbox       | [-1.704698202614825,49.60026075567804,-1.7041641314805869,49.60062217598128]
 datappro   | '20101213'
 datvalid   | '20101213'
 destdomi   | '08'
 FID        | 'zone_urba.35'
 gid        | 35
 idurba     | null
 idzone     | null
 insee      | '50187'
 lib_idzone | null
 libelle    | '1N'
 libelong   | null
 nomfic     | '50187_R_N.pdf'
 partition  | 'DU_50187'
 typezone   | 'N'
 urlfic     | ''
------------+-------------------------------------

I want to clip communes with PLU_0 and export the result as a CSV file, so I use this command:

mapshaper -i communes.shp PLU_0.shp combine-files \
     -merge-layers force \
    -clip PLU_0.json \
    -drop geometry \
    -filter-fields code,epci,partition \
    -o PLU_0.csv format=csv

This works but the CSV file is made of the layer information from the first layer and after information from the second one:

How I can "flatten" the information per item in order to have "code,epci,partition" with the relation in the same feature

Thanks for your help

[mbloch]

The clip command does not transfer attribute data from the clipping shapes to the target shapes (it sounds like this is what you want to do). You can try the -union command, which takes two target layers and combines them into a single output layer, while retaining attributes from both layers. After running -union, you would use -filter to retain only those shapes that have attributes from both of the input layers. Try running -union target=PLU_0,communes in the web UI console and inspect the result... that may put you on the right track.

[2803media]

@mbloch great thanks this is working as expected !

mapshaper -i communes.shp -i PLU_0.json \
    -union target=PLU_0,communes \
    -filter 'partition != null' \
    -o PLU_0.shp