topic Re: Import shapefile attributes - how to? in Talend Studio

Import shapefile attributes - how to?

hernandezpaul — Sat, 16 Nov 2024 09:59:26 GMT

Hi everyone,
I am using the spatial plug-ins to perform the following task. I have a dataset with X and Y coordinates. I have also a shapefile with multi polygons and two metadata attributes, name and Id. The idea is to look-up the names in the shapefile with the coordinates. With a point in polygon it will be determined to which polygon belongs a point.
I am using the shapefile input component which points to the .shp file.
I am facing to hurdles :
- I cannot retrieve the name and I'd from the file. I can only see an attribute call the_geom. How can I read the metadata?
- The second thing is, the file contains a multi polygon and I don't know how to iterate over it in order to perform a Contains or intersect with the points.
Any comment will be highly appreciated.
Kind regards, Paul

Re: Import shapefile attributes - how to?

Anonymous — Fri, 17 Mar 2017 12:14:11 GMT

Hi,
you could probably download the demo workspace https://github.com/talend-spatial/workspace-demo-spatial which contains some tMap making spatial join (eg. https://github.com/talend-spatial/workspace-demo-spatial/tree/6.x/DEMO-SPATIAL/process/Spatial/test_vector/Routines).
HTH
Francois

Re: Import shapefile attributes - how to?

hernandezpaul — Fri, 17 Mar 2017 16:42:17 GMT

Hi Francois,
thanks for the quick answer. The demo workspace is the right one for the version of the plugins I downloaded. I have downloaded another version which didn't help me.
Now it seems to work, at least I had a looked at how to create a shapefile schema in the metadata repository and I am able to see not only the geometry but also the others attributes. I hope I can have enough time to post my complete solution.
Great tools by the way
Kind Regards,
Paul.

Re: Import shapefile attributes - how to?

hernandezpaul — Sun, 19 Mar 2017 13:52:29 GMT

Hi, I solved almost everything. I want to briefly share my solution with you:
1) Create a generic schema under metadata:

2) This is the job overview:

3) I read the shape file using a sShapeFileInput component:

4) The shapefile contains multipolygons and I want to have polygons. My solution was to use a sSimplify component. I used the default settings.
5) The projection of the shapefile was "MGI / Austria Lambert" which corresponds to EPSG 31287. I want to re-project it as EPSG 4326 (GCS_WGS_1984) which is the one used by my input coordinates.
6) I read the x, y coordinates from a csv file.

7) With a s2DPointReplacer I converted the x,y coordinates as Point(x,y)

This part was tricky, I needed to swap the x, y assignment to x = Latitude and y = longitude because the points in the polygons have this format --> Point(lat, long)
8)Finally I created an expression in a tMap just to get the polygon, poin intersection. I guess a contains would also work:

I hope this helps someone else.
Kind regards,
Paul