3

I'm really new to QGIS and GIS software in general. I'm trying make a map travel time across different wards in a city, I have the average travel time and range between peak traffic and lowest traffic. Anyway, I joined the shapefile containing the polygons of each ward to a CSV file containing the above parameters (I joined via name ward 1, ward 2.....so on). I added 2 fields, one fore range and the other for average time (both integer values), i cannot find a pattern as to why only three of these rows merged properly.The attribute table, the last 2 columns are the ones that have been joined, as you can see most of them are null with the exception of threethis is the SCV files as you can see there are 2 integer columns with one string column These are the data types

The tables have joined, however all but 3 of the cells have a value of null and I cannot figure out why. The cells that do have a clue correlate with the CSV file. I'm properly stuck. These are the 3 values that have synchronized, I sorted in descending order so that all three show together Lastly, as I said I'm really new to QGIS and I don't know any code, so I'm sorry I cannot provide that.

  • Please Edit the question to contain a code block with some examples of key and join values (with an indication of which are successful) and a description of their datatypes. – Vince Apr 28 at 0:57
  • Thank you for responding, i have made changes to my post, adding a few pictures to make the problem more clear. However, I do not know any of the code since I'm really new to qgis, so I'm sorry that i cannot provide that. – Nikhil Sahu Apr 28 at 3:03
3

I presume you joined under Layer properties in this dialog:

enter image description here

Since only some features got values from CSV mostl likely ward names don`t completely match. You should check for differences (capitals, typos, double spaces..). Sometimes empty spaces can be at the beginning and end of the text. When importing CSV try using Trim Fields to remove spaces: enter image description here You can also use Field calculator to edit, clean or transform fields if needed.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.