All Questions
65
questions
1
vote
0
answers
250
views
Calculating area of polygons in EPSG:102022 in QGIS?
I am trying to calculate the areas of administrative regions in Uganda, using the EPSG:102022 projection. They are polygons. But everything I do produces areas in degrees rather than meters, giving ...
4
votes
1
answer
2k
views
Selecting polygon with the largest area in QGIS
I would like to select the largest number in a column of an attribute table by "Select by attributes" in QGIS to select the polygon with the largest area. How would be the expression for ...
- 181
2
votes
0
answers
507
views
Calculating area of voronoi polygons from real life data using QGIS?
I have an area, which I divided into voronoi polygons using data points. I have no problem creating the polygons.
Now the data points are on a coordinate system, where every degree represents one ...
- 21
1
vote
1
answer
2k
views
Area measurement in QGIS
I try to measure a polygon with Export/Add geometry columns tool. The units for area measurement are square meters.
The problem is that I get different area results for the polygon:
When the ...
- 4,072
10
votes
2
answers
9k
views
Calculating proportional area of polygon within another layer's polygon using QGIS
I have two polygon layers, 'model' and 'ntem', whose features overlap and intersect one another.
I would like to calculate the proportion of the area of the 'model' polygons which fit within each '...
- 497
1
vote
1
answer
801
views
How to calculate the area of polygon features within another polygon feature layer
As shown below, I would like to calculate the percentage of each red feature (landscape zones) taken up by a green feature (forest zone). So I need the summed percentage of forest zone for each ...
- 841
3
votes
2
answers
748
views
How to calculate area in sq m - troubleshooting projection issues in a global dataset in QGIS
I am using QGIS version 2.12.3.
I have 3 polygon shapefiles: A, B and the intersect of A and B, which we can call C.
All I want is to add a field to the attributes table of each shapefile giving ...
3
votes
0
answers
552
views
Drawing polygons with fixed area? [closed]
I am looking for a way to draw polygons with a fixed area. I am currently mapping farming options on field parcels. Some areas such as buffer strips run along features like rivers and hedgerows so ...
- 145
3
votes
1
answer
2k
views
How to calculate the form (or shape) factor of a polygon?
I am using QGIS to calculate the form (or shape) factor of polygons following what Louf and Barthelemy did here: http://rsif.royalsocietypublishing.org/content/11/101/20140924
The form factor is ...
- 31
1
vote
0
answers
559
views
calculating total area of multiple polygons in qgis [duplicate]
I wish to know the total area of all polygons within a shapefile layer.
So far I have added a new column to the attribute table that shows me the individual area of the polygons.I tried to copy the ...
- 645
3
votes
0
answers
454
views
Why do each of my buffer-polygons have different areas
I`m using Qgis 2.2 and 2.4 and loaded a wms-map using the coordinate system ERTS89 UTM 32N. I set 8 points (all in on shp-fileand in UTM 32N) on various locations on the map. After that i created a ...
- 31
6
votes
2
answers
2k
views
Wrong $area from field calculator (QGIS)
The area of the polygons in a layer, calculated by the field calculator with "$area" is wrong (much too big) for some polygons. If I draw the concerned polygon again, the area is calculated correctly. ...
- 283
8
votes
3
answers
4k
views
Remove Holes Existing Within a Single Polygon for a specific area in Qgis
I have a shapefile that consists of a single polygon. I have gaps within the polygon that needs to be eliminated, but only the ones that are less than 200m2.
I tried different ways but none of them ...
- 103
5
votes
2
answers
2k
views
Calculating area between two line shapes using QGIS?
I'm new to using QGIS (2.0).
I'm trying to calculate the sidewalk area of a city.
For that I have some shapes, extracted from Bentley Microstation, with the topology (facades, fords, fences, etc...)...
- 51
1
vote
4
answers
263
views
How can I calculate different polygons by different attributes?
I'm doing my master thesis and want to calculate different polygons (in QGIS 1.8 for Mac) in four different columns which I defined by different attributes. i.e. some of the attributes in the first ...
