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Using QGIS 2.4

I am currently importing a csv file with ~30,000 polygons (polygons in WKT format). I also have a United States shapefile. I have used the Clip function to get only the polygons that are in the US. When I go to save the new clipped shapefile as a CSV file with GEOMETRY set to AS_WKT, sometimes the number of lat/lon points is very long and so it cuts off, not finishing the polygon or multipolygon. Is there a way to set the export to include all points?

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  • I also am encountering this problem with very detailed polygons. For our purposes it is acceptable to simplify the polygon first and use the less detailed version with fewer points, but i would also like to know this as I would prefer to use the full accuracy of the data – James Jul 29 '14 at 16:30
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    Additional: I believe the limit may be a character limit, as I have created multilines, multipolygons, polygons etc. that are all so long that it cuts off and they all cut off after 8000 characters, regardless of if it's part way through a coordinate/how many coords/parenthesis have been printed etc. – James Jul 30 '14 at 9:15
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    Hello, unfortunately i have no big csv file to try the export/import with QGIS. Is there a way to provide us your csv file ? Then i will test and help you about the export/import. – Leasye Aug 7 '14 at 11:16
  • James, I believe that is the case and I wish there was a way to change that. Here is a csv/wtk file (bit.ly/1ojxmYS) of my data. I imported it using "Create a Layer from a Delimited Text File", selected Well Known Text as the geometry definition, and Polygon as the Geometry field. – user34739 Aug 8 '14 at 17:58
  • Could you clarify what we are supposed to see from the dataset you linked? It contains a lot of pretty simple polygons as far as I can tell. – underdark♦ Sep 18 '14 at 21:59
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I know this question is old of more than two years, but it didn't receive an answer till now, so I tried to answer it although it might be out of your interest.

I tested your data and I didn't have any problem of exporting the new clipped shapefile as a CSV file with GEOMETRY set to AS_WKT. Here is the process of what I did:

  1. I first converted the the boundary of US from multiple part to single part using Vector -> Geometry tools -> Multiple part to single parts
  2. Select only US boundary and excluding Alaska boundary to only limit the clipping boundary to where the small polygon are located. Alaska region does not contain any small polygon, that is why I excluded it from being part of clipping boundary, as you can see below:

enter image description here

  1. I used Clip tool to clip the small polygons from Vector -> Geoprocessing tools -> Clip and used small polygons as input file and selected US boundary as clip polygon, as you can see below:

enter image description here

  1. Here is the output of clipped small polygon, which I think you already reached to this result:

enter image description here

  1. Then, I exported the output clipped small polygon shapefile to CSV with GEOMETRY set to AS_WKT, and here is the output:

enter image description here

  1. You can compare the number of features in the WKT file and shapefile of the clipped small polygons, which is exactly same of 89,165 polygon:

enter image description here

I tested using QGIS 2.14.5, so maybe there is some improvements in the performance of exporting the shapefile to CSV with GEOMETRY set to AS_WKT, compared to QGIS version 2.4.

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