All Questions
6,729 questions
15
votes
2
answers
23k
views
Completely uninstalling and removing QGIS 2.8.1 on Windows Vista
I want to uninstall and completely remove QGIS installation from my computer (Windows Vista). I have uninstalled it and when i try to reinstall it says it is already installed on the system.
- 1,467
13
votes
3
answers
18k
views
Installing ECW for QGIS in Ubuntu 12.04?
I have followed various online help guides on how to make ecw for QGIS 1.8 work in Ubuntu 12.04. I had it all working in Ubuntu 10.04 but since migration to 12.04 no such luck.
Is there a guide that ...
- 139
8
votes
2
answers
10k
views
Getting incorrect slope values from an ASTER DEM in QGIS?
I have a DEM layer from ASTER satellite and I want to get the slope information from it.
I use terrain analysis > slope, but the output is so wrong. Why is that?
Here is the DEM:
And here is the "...
- 695
5
votes
2
answers
4k
views
Layer disappears when changing from CRS in degrees to CRS in meters in QGIS
The problem
I have tens of thousands of small polygons for which I want to create buffer/doughnuts for, but I don’t get the units right. I want meters and not degrees, and changing to (what I think ...
- 155
66
votes
3
answers
107k
views
Installing latest QGIS version on Ubuntu? [closed]
I am relatively new to Linux, so can you indicate the exact commands (step-by-step) that I need to type to get the latest QGIS installed on Ubuntu 14.04.
I have tried to follow the instructions ...
- 769
50
votes
8
answers
37k
views
Creating svg symbols that have modifiable fill color, stroke color and stroke width
I want to create some svg symbols for QGIS using Inkscape, those symbols must have attributes as described in the question. For the last two days, I have been experimenting as instructed by Sourcepole ...
- 2,024
20
votes
2
answers
16k
views
Calculating distance to points in QGIS
Is there a way of calculating the distance to the nearest points in QGIS?
In ArcGIS Desktop there is a function called Euclidean Distance, which can take an input vector or raster, and generate a ...
- 16.3k
18
votes
6
answers
22k
views
Show images related to features in QGIS?
Say for example, if there's a point data with old trees, then when you use the identify tool, you can see the photograph of the tree
Or even one level further, the labels displaying these images ...
- 2,350
89
votes
6
answers
63k
views
Visualising WKT geometry string in QGIS
Is there a simple tool in QGIS to graphically visualise geometry formatted as text?
Example geometry:
POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 6337246,571178 6337246))
Result:
A ...
- 4,520
65
votes
5
answers
47k
views
Building effective heat-maps?
Using ArcGIS, QGIS, Grass, and/or GVSIG:
What are some of the tools and processes involved in building effective heat maps?
What are the plugins involved?
What are the major data requirements?
What ...
61
votes
7
answers
226k
views
Importing DWG into QGIS project?
I have a lot of DWG files like basemap, and water and wastewater network.
How do I import these files into my QGIS project?
- 667
46
votes
3
answers
86k
views
Displaying only selected features on map in QGIS
Not sure if this option ever existed, but the new QGIS version hides a lot of things somewhere else and this seems so simple that I'm kind of convinced it was possible to do this before.
I have quite ...
- 1,093
40
votes
4
answers
11k
views
Generalizing polygon file while maintaining topology in QGIS
I have a polygon shapefile, which I need to generalize.
How can I generalize the polygons and ensure that there are no topological errors like slivers?
I have already tried:
Vector -> Geometry ...
- 7,235
26
votes
7
answers
67k
views
Creating points in specified distance along line using QGIS
I want to use QGIS creating points along the line, but in specified distance. I found two GRASS tools in SEXTANTE Toolbox：
v.to.points
v.segment
I tried v.to.points, setting the maximum distance ...
- 1,555
18
votes
3
answers
30k
views
Getting tabular statistics from table using QGIS?
Are there QGIS tools that will allow users to get tabular statistics from their table? I kind of expected I would be able to just open the table, select the field I was interested in, right-click on ...
- 23.2k
16
votes
3
answers
39k
views
Summing data from column in QGIS Attribute table
I'm working with population data, and I have an issue when it comes to knowing the sum of a population inside the attribute table.
In my attribute table, I'd like to add all the numbers in the red ...
- 1,042
16
votes
4
answers
43k
views
Transforming polygon to linestring in QGIS
I have a polygon, imported from a shapefile in QGIS. I would like transform it to a linestring instead so I can save it as a GPX file later.
How can I transform a polygon to a linestring in QGIS?
- 2,231
14
votes
4
answers
7k
views
Styling border to match fill in QGIS?
In the past I have just manually matched the color of the border to the color of the fill, but this can be time consuming.
I am wondering, is there any way to have the program automatically match ...
- 2,324
12
votes
2
answers
9k
views
Scale and Z factor have no effect on hillshade analysis in QGIS
I used an SRTM DEM to create a hillshade in QGIS 2.2.0. However, the resultant hillshade seems to be vertically exaggerated. Also, changing the settings for scale and z-factor does not have any effect ...
- 1,660
11
votes
3
answers
6k
views
Summing up values of overlapping polygons in QGIS
I have large single layers with many features overlapping.
Simplified example with 50% transparency:
Where the features overlap I want the attributes added together. I manually created the output I ...
- 411
10
votes
4
answers
15k
views
How to fix QGIS error "Entry Point could not be located"?
Today, after returning from vacations, I started my QGIS 1.7 and got this terrible message:
Help, anyone?
- 5,616
8
votes
2
answers
14k
views
Spatially joining polygon fields onto point layer in QGIS
I have gridded depth points in CSV format that I'm trying to add other map data to, in additional columns. I've tried joining fields, hoping that I could link the shapefile data to the CSV, but when I ...
- 1,089
5
votes
1
answer
3k
views
Raster incorrectly reprojected to OSGB(27700) using QGIS [closed]
I am using Ubuntu 12.04, QGIS 1.8.0, GDAL/OGR 1.7.3 and GEOS 3.2.2
Open a Spatialite db with OS Mastermap poly layer (EPSG:27700);
Add OpenLayers Plugin (1.0) from QGIS offical repository;
Add a ...
- 59
54
votes
4
answers
43k
views
Making spatial view in PostGIS and adding it as layer in QGIS?
In PostGIS 2.0, I am seeking an efficient way to create a spatially enabled view that is viewable in QGIS.
I followed the context of Part 2 of @Mike Toews answer to How to create a table from ...
- 23.2k
53
votes
8
answers
19k
views
Switching line direction in QGIS
I would like to be able to swap the direction of a polyline/line in QGIS. I made a custom tool to do this in MapInfo, however I can't seem to find anything for QGIS.
Does anyone know of a tool to do ...
- 35k
52
votes
9
answers
59k
views
Identifying duplicate attributes in field using QGIS
I have a point shapefile with thousands of points. It has an "ID" code field that is supposed to be unique. Every now and then the data entry clerk wrongly type the "ID" creating ...
- 523
50
votes
4
answers
65k
views
Joining non-spatial CSV file to spatial data (shapefile) using QGIS
I have a CSV file which has postcode data in a field, but it is non-spatial e.g. no Easting and Northing.
I have a shapefile with postcode in a field and some additional data.
I want to join the ...
- 545
47
votes
10
answers
114k
views
Determining the centroid of polygons in QGIS
I have a polygon vector and I want to quickly attain the centroid of this polygon for insertion in a text document. I am working with QGIS. I searched through other questions and although some are ...
- 781
44
votes
7
answers
154k
views
Creating new layer from selection in QGIS
Is it possible to create layers from selection in QGIS? I am using QGIS 1.7.4-Wroclaw.
To make it easier for others to see this, here are some pics. I used QGIS 2.0.1-Dufour.
Selecting
Saving
Adding
- 957
36
votes
3
answers
21k
views
Was QgsMapLayerRegistry being removed in QGIS 3?
Is QgsMapLayerRegistry going to be availabe in PyQGIS with QGIS 3?
When I typed it into the QGIS python console (2.99), python seems to recognize it because it auto-completes qgis.core....
- 11.2k
34
votes
2
answers
42k
views
Converting point sets to polygon boundaries?
I'm trying to convert sets of points to their respective polygon boundaries. I think this is something like a Voronoi diagram or Convex Hull, but not quite. I'm sure there's a technical term for it, ...
- 589
29
votes
4
answers
94k
views
Converting vector layer to raster using QGIS?
In qgis in the raster menu there is an item "convert vector to raster".
This behaves strangely - I do not understand how it is supposed to work.
I can select a vector file, an attribute and an ...
- 885
25
votes
5
answers
19k
views
Creating equidistant points in QGIS?
I am trying to create points (new layer) at specific distance along the road (existing layer) in QGIS. Creating Regular points every meter at county level using ArcGIS Desktop?
gives solution for ...
- 957
21
votes
5
answers
23k
views
Splitting vector into equal smaller parts using QGIS
How do I divide a shapefile with many tiles into a lot of smaller tiles using QGIS?
I am searching for a smart solution, because manual edits are out of questions
- 8,180
17
votes
7
answers
32k
views
Georeferencing DXF using QGIS? [duplicate]
I have got myself a dxf which is built with units in the wrong scale. How do I upscale that in QGIS? Note it does open in QGIS, just in the wrong map units and location.
- 3,520
16
votes
3
answers
24k
views
Creating centerline of river in QGIS? [duplicate]
I made two river bank lines and I want to associate them.
I want to make a centerline using two rows as a base. I managed to make the centre line with a lot of work creating several lines from one ...
- 161
16
votes
5
answers
28k
views
Reading ODBC connection using QGIS? [closed]
I have a co-worker who manages a large MS Access database that contains X & Y fields for various locations he tracks. We have previously exported the data to CSV and used the QGIS Delimited Text ...
- 23.2k
15
votes
16
answers
76k
views
Redefining nodata value into zero in QGIS
I have an image which I clipped with an AOI polygon. The contour area was set to pixel value = 0 and I have a nodata value of -32768. I want to redefine the nodata value into zero. I used to do this ...
- 5,616
15
votes
3
answers
3k
views
Convert vertices of polygon features to points using Virtual Layer in QGIS
I have a polygon layer and want to use a Virtual Layer that creates points from the vertices of the polygon layer. The question is how to write a query that does this?
I am aware of the tool "...
- 74.9k
8
votes
6
answers
3k
views
Creating line segments between all points in QGIS
I want to connect all points in a point feature with every possible line segment using QGIS.
For example, how a pentagon has five points with ten line segments connecting them all to form a pentagram ...
- 181
5
votes
3
answers
2k
views
Using QGIS model output in same model as layer in field calculator formula
I am trying to use field calculator within a model. In this formula I want to reference the output (temporary layer) of another step of the same model (output objektfilter_strassen_wege, which is ...
- 61
4
votes
2
answers
19k
views
How to reclass a raster with reclassify grid values in QGIS?
I'm new in QGIS and I'm trying to reclass a raster with reclassify grid values.
I want to reclassify by table, however fixed table has only 3 rows and I need some more, but button to add is not ...
- 41
49
votes
8
answers
189k
views
Exporting attribute table to Excel from QGIS
I have seen all the questions for how to export an attribute table to Excel from QGIS, and I try all the answers like copy paste, CSV (in fact this I do not know where to find), but none seems to be ...
- 851
46
votes
9
answers
49k
views
GRASS not working with QGIS says This algorithm cannot be run
I updated QGIS to version 3.6 using OSGEO4w
When I try to run any GRASS script, I get the following error message :
This algorithm cannot be run :-( The specified GRASS 7 folder
"C:\OSGEO4~1\...
- 1,937
37
votes
6
answers
59k
views
Converting .shp into .gpx using QGIS
I would like to convert .shp into .gpx.
Using GIS, I open my shapefile and I tried to "save as" gpx but it gives an OGR error:
creation of field ObjectId failed (OGR error: Field of name '...
- 951
34
votes
3
answers
11k
views
Can QGIS preserve layers when exporting to PDF?
In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself). When I export from QGIS to PDF, I don't ...
- 23.2k
32
votes
12
answers
54k
views
Converting KML to shapefile without losing attributes using QGIS
I have a KML file with hundreds of points. To each point there is information, such as Name, Power, Age (it's a map of hydroenergy powerplants). If I import that KML file to QGIS, this information is ...
- 321
30
votes
2
answers
24k
views
Seeking QGIS equivalent of ArcGIS Erase tool?
Is there a QGIS equivalent of the Erase tool in ArcGIS Desktop?
The Erase tool:
Creates a feature class by overlaying the Input Features with the
polygons of the Erase Features. Only those ...
- 1,149
29
votes
4
answers
92k
views
Merging/Dissolving polygons by Common Attribute Field in QGIS?
I have joined corresponding Local Enterprise Partnerships table data into a polygon shapefile containing UK Local Authorities.
How do I Dissolve or Merge the the Local Authorities polygons by ...
- 471
25
votes
3
answers
13k
views
Assigning row number for sorted table by column in QGIS
In QGIS 3 the Field calculator has a great function called @row_number (in QGIS 2 it was $rownum) which returns (assigns) the number of the current row.
Is there a way to make it work together with ...
- 9,794