Linked Questions

0
votes
1answer
2k views

Getting area of polygons in QGIS [duplicate]

I have a world map divided into zones and need to compute the area for each polygon. I tried using Vector > Geometry Tools > Export/Add geometry columns and successfully get the area and perimeter but ...
13
votes
2answers
39k views

How to calculate polygon areas and perimeters using QGIS?

Using QGIS, if I load a polygon layer and make a new column, how do I fill that column with the: area of each polygon and another column with length of the perimeter of each polygon?
9
votes
3answers
633 views

Programmatically finding polygons which are >90% overlapped by another vector polygon layer using QGIS?

I'm trying to figure out how to use python to extract the polygons in one vector that are overlapped by >90% by another vector. I would then like to have a vector/map that will only show those ...
3
votes
4answers
940 views

CRS for calculating areas in Mexico

I'm using QGIS 2.0.1. I want to compute areas (in km^2) of all municipalities in Mexico. I understand that I need to convert my map from WGS84 to UTM to get units in km, but I'm not sure how to ...
0
votes
1answer
3k views

How to calculate polygon areas in acres or square miles instead of feet?

I have a layer in State Plane NAD83. When I use "Vector|Geometry Tools|Add/export geometry columns" or Field Calculator they both create the area in feet. What if I want acres or square miles? Thanks ...
4
votes
2answers
3k views

How to calculate the area of a polygon in a WGS84 Shapefile in QGIS?

I am using QGIS 2.12.3 Lyon and I want to calculate the area of my polygon in m2. For that I used the tool provided by QGIS, but the result is not as it should be. I got from QGIS 50 ha, while I got ...
0
votes
2answers
2k views

Calculating area of raster using QGIS?

I have this raster wich represent some areas of observation from 3 given points following a series of rules considering elevation and direction of the slope. Basically, the white-ish color represent ...
0
votes
2answers
601 views

Calculating Ha of specific fields in QGIS?

I use QGIS Bonn 3.2.0 So my question is how can i calculate Ha for specific fields i marked on picture. Is there any tool and if yes which and how to use it?
1
vote
2answers
1k views

How to re-calculate area, perim, p2a,width and length in QGIS?

I cut a part out of one feature and added it to another feature in a polygon shapefile. My problem now is that both features has the same values in the area-, perim-, p2a-, width- and length-columns? ...
4
votes
1answer
366 views

Surface covered by buffers in QGIS

In QGIS, I have plotted buffers around points. I would like to calculate the area which falls under buffers without over counting due to buffer overlaps. Is there a quick and easy way to do this?
0
votes
2answers
830 views

Zonal stats for two polygon layers: calculate proportion of feature cover within polygons

In order to calculate land cover diversity within defined patches, I need the coverage proportion of each landcover type for each patch. So I am searching for something similar to the zonal stats tool ...
1
vote
1answer
529 views

How do I find the percent overlap between two shapefiles in QGIS?

I have two different shapefiles (first and second). I want to calculate how much overlap there is between the liquefaction zones in the second shapefile and each of the neighborhoods in the first. I'...
2
votes
1answer
290 views

Converting clustered hexagonal grid units into polygons

I created a hexagonal grid using MMQGIS for my project and after some selection, I ended up with several clusters of units (as can be seen in the picture). I define as a cluster all the small ...
1
vote
1answer
284 views

Analyse spatial data and extract results in tabular form in QGIS

I'm sorry if this question is badly framed, I only started with GIS and QGIS 2 days ago so I don't know any terminology yet - I'll try to explain as best I can. I have 2 layers in QGIS (1.8, on Win7),...
1
vote
0answers
356 views

How to calculate area of a contour in QGIS [closed]

I have prepared a contour map of an area in a shapefile in QGIS. I want to know how can I calculate area of a particular contour?

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