Create a script to add delimited text layer in QGIS

Question

I'm trying to use QgsVectorLayer() function to add delimited text layer in QGIS. So I have a txt file (T_1999_1_2.txt) in path: "D:\PATRICIA\DOCUMENTOS\ESTACOES METEOROLOGICAS\DADOS METEOROLOGICOS\T" and I want to create a shapefile named: T_1999_1_2.shp. The txt file structure is:

par;num;ano;mes;dia;D;btq 3;705;1999;1;2;-999,9;S;40,43885833;-8,43994167
3;619;1999;1;2;25,0;A;41,70972;-8,02699 3;718;1999;1;2;104,0;A;39,78055278;-8,82096667 3;766;1999;1;2;28,0;A;38,76620278;-9,12749444 3;560;1999;1;2;333,0;A;40,71492778;-7,89591667 3;669;1999;1;2;-999,9;S;39,83950000;-7,47866944 3;848;1999;1;2;-999,9;S;38,48486667;-7,47291667 3;555;1999;1;2;8,0;A;41,70655556;-8,80210833

I have tried to run the script but appears the same window error ("Error in file. File cannot be opened or delimiter parameters are not valid") My sript is the following one:

uri = "D:\PATRICIA\DOCUMENTOS\ESTACOES METEOROLOGICAS\DADOS METEOROLOGICOS\T\T_1999_1_2.txt?delimiter=%s&xField=%s&yField=%s" % (";", "x", "y") 
vlayer = QgsVectorLayer(uri, "D:\PATRICIA\IG\QGIS\FWI\T\T_1999_1_2.shp", "delimitedtext")

I don't understand, why it doesn't work.

• underdark: Please fix the line breaks in your question. Also, it seems like there are no x and y columns in your CSV but they are specified in the uri definition. Finally, it seems like you are mixing parts related to opening the CSV with parts for writing a Shapefile.

Answer 1

Change variables indir and outdir according to your need. The code will find each file with extension 'txt' in indir and every subdirectory of indir. If you need another coordinate system than EPSG 4326, please change the EPSG number in line 9. The converted files will be written to directory outdir.

import os
indir = 'G:/LANUV'
outdir = 'G:/LANUV'
for root, dirs, files in os.walk(indir):
 for file in files:
 if file.endswith('.txt'):
 fullname = os.path.join(root, file).replace('\\', '/')
 filename = os.path.splitext(os.path.basename(fullname))[0]
 uri = 'file:///%s?crs=%s&delimiter=%s&xField=%s&yField=%s&decimal=%s' % (fullname, 'EPSG:4326', ';', 'x', 'y', ',')
 layer = QgsVectorLayer(uri, 'my_layer', 'delimitedtext')
 QgsVectorFileWriter.writeAsVectorFormat(layer, outdir + '/' + filename + '.shp', 'CP1250', None, 'ESRI Shapefile')

Copy the code and paste it into the Python console.

This code fragment uses code from this thread.

• Patrícia Fernandes: Thank's Detlev, the scritp is running. Had to adapt to my characters. Now my problema is solved

Answer 2

You have to change several things in the csv file and the code.

In the first line of your csv file add the column labels x and y, since they are missing. The other labels are fine.

par;num;ano;mes;dia;D;btq;x;y

Since your decimal separator isn't the default colon but a comma you have to specify this explicitly. The fully qualified file name hasn't the required URL format. You have to change the line of code like this:

uri = "file:///D:/PATRICIA/DOCUMENTOS/ESTACOES METEOROLOGICAS/DADOS METEOROLOGICOS/T/T_1999_1_2.txt?delimiter=%s&xField=%s&yField=%s&decimal=%s" % (";", "x", "y", ",") 

Then you are ready to create the layer. If you want to add the layer to the map you can use the following line:

layer = iface.addVectorLayer(uri, "my_layer", "delimitedtext")

The second argument is the name of the created entry in the table of contents. You are prompted to give the coordinate system and the layer is added to the map.

Without adding the layer to the map automatically you may code like this:

layer = QgsVectorLayer(uri, "my_layer", "delimitedtext")
QgsVectorFileWriter.writeAsVectorFormat(layer, "d:/b/my_shapes.shp", "CP1250", None, "ESRI Shapefile")

You will be prompted to give the coordinate system after the first line. If you want to stop this behaviour, you to temporarily change QSettings as shown in this thread.

The second command writes the layer to a shpe file with the given file name using codepage 1250. Mention the "/" instead of "\". If you like you may catch the return value. If is not equal 0 then something went wrong.

To add the layer to the map display:

QgsMapLayerRegistry.instance().addMapLayer(layer)