All Questions
117
questions
123
votes
8
answers
354k
views
Calculating polygon areas in shapefile using QGIS
How do I calculate areas of an area shapefile in square meters (m²) or in acres (ha)?
I didn't find that functionality in the Vector Tools.
- 2,321
54
votes
2
answers
91k
views
Understanding difference between Polygon and Multipolygon for shapefiles in QGIS?
Creating Scratch layer gives me a choice between Polygon and Multipolygon, so I started wondering how should I make use of them.
Reading a new book "Mastering QGIS" (through this answer by Joseph to ...
- 31k
17
votes
3
answers
14k
views
Inverting Polygons using QGIS?
I have a Shapefile with Polygon features representing the world's land areas (continents, islands).
Is it possible to invert these, and get a geometry that represents the world's oceans and seas?
...
- 802
12
votes
3
answers
7k
views
Voronoi Diagram on a given polygon using QGIS
I am trying to create a Voronoi Diagram on a specific polygon, but there is some issue when dealing with edges.
Here is how I do it:
Preparing the points for Voronoi and the polygon for the diagram
...
- 365
7
votes
2
answers
275
views
Dissolving polygons that intersects in QGIS
I want to gather all the polygons in my shapefile that intersects with each other in several groups. If they had shared a common field I would have used the "Dissolve" tool but they don't ...
- 347
7
votes
1
answer
10k
views
How to make a multi color map with one shapefile layer in QGIS?
I am working with a shapefile layer of the world. All the countries are in the Attribute table each one in a different row.
I tried to make each polygon in a different color so the countries will be ...
- 2,857
7
votes
2
answers
2k
views
Calculating shortest distance between points within polygon using QGIS?
I performed a transect in which I sampled several animals. The location of these animals are represented by a point shapefile. I am interested in calculating a pairwise matrix of distance (in meters) ...
- 371
6
votes
1
answer
2k
views
Turning vector grid into individual shapefiles using QGIS?
I am using QGIS and I created a vector grid on a crop field in order to cut it into plots. I want to save each grid cell into individual polygon shapefiles automatically.
Here is an example of a ...
- 63
6
votes
1
answer
608
views
Non-existent polygon inside polgyon
I inherited some shapefiles that I've been trying to clean up in QGIS and Grass. The shapefile is a large area covering a watershed, the person who digitized it, did so in small chunks without using ...
- 63
5
votes
2
answers
1k
views
Intersecting area between two polygons in the same shapefile in QGIS
I have a shapefile with two polygons in it. I would like to be able to generate the intersecting area between the two polygons.
Please note, I have tried using the intersect tool, however this does ...
- 241
5
votes
1
answer
2k
views
Import CSV into polygon shapefile
I have commune level map in shapefile and CSV.
Originally, I have shapefile, exported it to CSV, then to STATA for data manipulation. Then I have exported it as CSV to import to QGIS as polygon.
I ...
- 173
5
votes
1
answer
277
views
Creating polygons with "Create shapefile layer" always produce multipolygons instead of polygons when saving in QGIS
Not sure if is a bug or I'm missing something.
Every time i'm creating a new shapefile with "Create shapefile layer" i got a multipolygon instead of a polygon (at least is what I'm expecting)...
- 233
5
votes
2
answers
11k
views
Selecting features of vector layers based on another vector layer using QGIS?
I am using QGIS 2.12.2. I am using three vector layers (point, polyline and polygon shapefiles) of the region of interest. Any advice in making the selections from one dataset based on the other ...
- 1,081
5
votes
3
answers
2k
views
How to combine stacked polygons within a shapefile?
The image below shows my shp-file. Every polygon has the same transparent color. So a darker blue means, that several polygons are stacked! How do I cut every polygon with each other so no polygons ...
- 8,338
5
votes
2
answers
2k
views
Automating selection and sliver elimination using QGIS
At the moment I do this manually:
open a shapefile
open the attribute table
use "select features using an expression" - the expression is "area" < 200
then I use vector/geoprocessing tools/...
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