1
vote
1answer
29 views

*Value relation* widget in QGIS

I cannot understand what the Value Relation widget of the Fields menu in QGIS actually does. For example: I have a point layer with some columns (ID, value1...) and a table (so just a dbf file) with ...
1
vote
0answers
31 views

QGIS 2.4.0 Chugiak “reduced” real-type numbers. Precision problem? Bug?

I have a SHP point file created from CSV with QGIS 2.4.0 Chugiak. It contains some data on noise in a certain point. When I import from CSV, it seems to be fine, but when I export to SHP and open the ...
2
votes
1answer
46 views

QGIS: Expression WHEN property1 = 'FOO' THEN property2 = 'BAR'

Our Foundation is adding additional properties to points. If property1 = FOO , then add property2 = BAR WHEN property1 = 'FOO' THEN property2 = 'BAR' END When I run this the ...
3
votes
2answers
122 views

How to set NULL as default value for a date field in QGIS 2.4?

In QGIS 2.4, i am unable to set the default value as NULL if i have not updated any value on date fields. Its automatically taking the current system date. I am expecting to set the default ...
0
votes
2answers
53 views

Using the Rule-based style to calculate each grid cell from overlaps

I am using the Rule-based styling properties (QGIS 2.2) to determine the colour of grid cells for a merged shapefile. Each grid cell defined by its ID may be overlapped by several layers as defined by ...
0
votes
1answer
59 views

Modifying Fields in QGIS

I'm pretty new to Quantum GIS, and I was looking to add zeros to a field I was having some trouble with. I learned through browsing a few posts here that existing fields can be modified by defining ...
1
vote
1answer
33 views

QGIS how to add string field

I have a few point shapefiles. I want to merge them, but first give each point a certain type according to shapefile. How do I add a String field, all with the same word? (changing the field type ...
3
votes
1answer
63 views

How do I add a field to a table using the QGIS graphic modeler?

I was wondering if anyone could help as I'm struggling to get anything out of the QGIS graphic modeler. For info I have no programming skills whatsoever. I need to be able to add a new field to an ...
1
vote
1answer
35 views

Expression to create and populate column based on filtered fields

I wanted to create a column and populate it with data based on data from other fields. If column_1 contains fields which has similar string (eg. field_1 = "Country: UK", field_2 = "Country: US", ...
1
vote
1answer
51 views

Create and immediately update field using Field Calculator

You can create fields and once created, populate them with data using the Field Calculator. But can you do both at the same time using an expression? Or must you do it in 2 steps?
8
votes
5answers
304 views

Print out the properties of the attribute table in qgis?

I have to merge a lot of shapefiles into one great shapefile. So I want to compare the properties of the attribute tables to see if there are differences between the tableproperties of each shape ...
0
votes
1answer
56 views

Can QGIS report/calculate areas/perimeters of individual polygon components within multipart shapefile?

Can QGIS report/calculate the areas/perimeters of individual polygon components within a multipart shapefile without using the "explode" vector tool to generate a new file? using QGIS 2.2.0 on ...
0
votes
0answers
42 views

How to add field to postgres layer with PyQgis?

I'm fetching a posgtres layer with PyQgis and then I'm trying to add field with this: lyr.startEditing() lyr.addAttribute(QgsField("class", QVariant.Int)) But It is not adding the field and also ...
0
votes
0answers
43 views

QGIS grabs incorrect field values for categorized style classification

as seen in the first image, the field values QGIS returns when I attempt a 'select by expression' are values found nowhere in the field in question ('FLD_ZONE'). Instead, it returns a selection of ...
1
vote
2answers
169 views

How to add a new column in attribute table with attribute with indexes of another max-min ordered attribute field?

I've an attribute column named e.g. VALUE with different values I would like to make a column named e.g. ORDERsuch that the greatest value has the attribute 1 the second value 2 etc. etc. so order ...
1
vote
1answer
278 views

How to use UUID Generator in Qgis 2

I try to generate a UUID (edit widget) for a vector shapefile in qgis 2 but the field value is always NULL. Does the field requirea specific datatype? I used integer. In the manual I found the info ...
6
votes
2answers
502 views

How to specify fields to export from QGIS?

I'm using QGIS 2.0.1 and am connected to a MS SQL Server spatially enabled database (not ESRI). I am able to connect to the layer and load it into my TOC just fine. I have hidden a number of fields ...
0
votes
0answers
16 views

Selecting Particular field in attribute table in qgis [duplicate]

I am having a shape file which contains following fields such as shape area ,shape length,locality ,sub locality etc.My aim is to select only a particular field say for example locality and I want to ...
0
votes
2answers
102 views

Attribute Table Doubt in Qgis

I am having a shape file which consists of various fields for example: shape area ,shape length, locality, sub-locality,district etc.In my company they are demanding seprate shapefiles say for example ...
0
votes
0answers
40 views

Reading particular fields in attribute table and exporting it as a text file

I am having a shape file for which i created a polygon centro ids using qgis. When I open the attribute table it shows various fields such as shape area, shape length,unique id x coordinate and y ...
0
votes
0answers
76 views

How to add a field to a .zip shapefile?

I am exploring the possibility of using ArcGIS Online (Free Public Account and Explorer) with my new Global Studies students. (So far, the Free Public Account appears to be more user friendly and ...
2
votes
1answer
482 views

How to create a date field in QGIS shapefile

When I create a new shapefile in QGIS, I'm presented with the "New Vector Layer" window, where I specify the Shapefile type (Point/Line/Polygon) and am then able to create attribute fields. I'm only ...
0
votes
1answer
224 views

qgis how to assign a field to map tips

I am a beginning user of QGIS 1.8. I cannot find the way to assign a field to 'map tips'. There seems to be no way in 'properties' of the layer to do so.
11
votes
2answers
245 views

How to sort by multiple fields at the same time?

Is it possible to sort multiple fields at the same time in QGIS? For example, I'd like to sort a table by state name, and then within each state, sort by county name. This would be the same as the ...
2
votes
1answer
123 views

How to hide all fields at once in QGIS 1.7

Is there a way to hide all the fields at once in QGIS 1.7? I see where I can hide one field at a time but I would like a button which does it all at once.