Questions tagged [area]

Area is a quantity that expresses the extent of a two-dimensional surface or shape, or planar lamina, in the plane.

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92
votes
5answers
208k views

Calculating polygon areas in QGIS?

How do I calculate areas of an area shapefile in square meters or in acres (ha)? I didn't find that functionality in the vector tools.
13
votes
2answers
44k 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?
7
votes
2answers
4k 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 ntem ...
14
votes
5answers
21k views

How can I measure area from geographic coordinates?

If I have polygons in geographic coordinates (WGS84), how do I measure the total area each takes on the surface of the earth, taking into account the curvature of the earth?
2
votes
3answers
2k views

Calculating percentage of overlap of two layers in QGIS 3

I am trying to compare two different vector layers on QGIS 3. They are species distribution maps. I would like to calculate the percentage of overlap of two vector layers. My goal is to determine how ...
6
votes
2answers
2k views

Deleting polygons smaller than certain dimension using ArcGIS Desktop?

I've made a model in ModelBuilder in ArcMap 10.3, what it basically does is creating polygons over open areas such as farm-lands, grass-lands, marshes etc that has a low slope. My challenge is that I ...
8
votes
1answer
6k views

Calculating area weighted average of attribute in one layer by shape in another using ArcGIS for Desktop?

For a project I am working on I would like to intersect fire station response districts with income data to determine the median income per response district. However the borders of the layers ...
3
votes
2answers
7k views

Area is calculating wrong using $area in field calculator (QGIS 2.8.1-Wien)

There is a similar question posted, but the solution to it seems to be that polygons were multipart: Wrong $area from field calculator (QGIS) In my case, all polygons are singlepart. I have several ...
3
votes
5answers
37k views

How to calculate a percentage of an area covered by polygons ArcGIS 10.1

I created an Aspect Layer with 9 Zones on which I want to use the Tabulate Area Tool with another polygon layer namely Woods. So what I actually need to know is the percentage, covered by woods for ...
18
votes
6answers
26k views

Removing only donut holes from polygons using ArcGIS Desktop?

I am using ArcGIS Desktop 10.0. I have a trick for removing the donut holes, which is converting the polygon to line and then creating polygon out of the lines and in the end merging all of them. ...
11
votes
3answers
4k views

More accurate way to calculate area of rasters

In my daily work, I am constantly asked to calculate areas of global raster datasets in geographic projection at 30 arc second resolution. These datasets are normally the result of a Combine operation ...
6
votes
2answers
608 views

Increase each polygon area to the same area

I'm using ArcGIS Desktop 10.2. I have many polygons (buildings) with various areas and I want the same area for all my polygons: 100m². The final goal is to aggregate them and build the urban ...
4
votes
2answers
3k views

Calculating 3d polygons' surface area using ArcGIS Desktop?

I've got a polygon feature class with Z values enabled. The polygon entities represent billboards. I'm looking for a way to measure the front surface area of this entities - i.e the area of the ...
6
votes
1answer
3k views

How to calculate te area between contour lines on a DEM with QGIS 1.8?

Does anyone know how to calculate the area in km² for each altitudinal band (between 100 and 200, 200 and 300...) based on a DEM? I added the contour lines with a distance of 100 metres but could not ...
22
votes
3answers
23k views

Getting polygon areas using GeoPandas

Given a GeoPandas's GeoDataFrame containing a series of polygons, I would like to get the area in km sq of each feature in my list. This is a pretty common problem, and the usual suggested solution in ...
8
votes
2answers
8k views

How to calculate area of 1 x 1 degree cells in a raster

I have a simple array (not geo-referenced in any way) in Matlab (which is not a language I know a huge amount about...so I can export it to other languages if needed) which has the dimensions 180 x ...
4
votes
3answers
17k views

Calculating projected area of polygons with field calculator in ArcMap?

I've got a polygon featurelayer in ArcMap 10. The coordinate system of the featurelayer's featureclass is web mercator. The dataframe of the map uses an equal-area projected coordinate system. I've ...
5
votes
3answers
14k views

Calculating area of rasters in QGIS?

I have been working with some rasters and would like to know how to calculate the area occupied by one element of a raster in QGIS?
5
votes
2answers
3k views

How to find the area of raster values within polygon zones?

I'm using ArcGIS 9.3 and I just can't seem to get this right - I've tried tabulate areas, zonal stats, converting to polygons, etc. I'm missing something somewhere. I have a USGS impervious surface ...
5
votes
2answers
16k views

Converting Longitude and Latitude Coordinates to Square Miles?

I have a set of Long and Lat co-ordinates making up a five point polygon which I have converted in excel using the following formula: =((X1*Y2)-(X2*Y1)+(X2*Y3)-(X3*Y2)+(X3*Y4)-(X4*Y3)+(X4*Y5)-(X5*Y4)+...
4
votes
2answers
3k views

Calculating area of polygon in WGS84 Shapefile using 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 ...
3
votes
2answers
2k views

Updating polygon areas in QGIS?

I'm using QGIS 2.6 and regularly update a shapefile layer to indicate felling progress. However, if I edit the nodes of a polygon, save the layer out then look at the Attributes table the area shown ...
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? ...
0
votes
2answers
259 views

Group points and compute area

In a point vector layer, how to compute area for 4 defined ranges of values of one attribute? On the example below, I want the total area for each of the 4 colours.
17
votes
1answer
25k views

Calculate area within Python script in ArcMap

I am trying to calculate the area of a polygon within my Python script. I create a new polygon from merging two together, and I'd like to add the area of the resulting polygon to a field in the output ...
18
votes
5answers
19k views

Area in KM from Polygon of coordinates

I have polygons from coordinates in (python shapely) that looks like this POLYGON ((24.8085317 46.8512821, 24.7986952 46.8574619, 24.8088238 46.8664741, 24.8155239 46.8576335, 24.8085317 46.8512821)) ...
10
votes
3answers
9k views

Splitting irregular polygon into equal areas using QGIS?

I am a surveyor and use QGIS for maintaining soil test records on civil projects and am constantly provided with test lot area or number of lots required. These are more often than not irregular in ...
8
votes
1answer
8k views

How to measure areas of features in OpenLayers plugin background maps correctly?

I can't figure out how to make areal calculations (eg. in km2). I have tried the 'field calculator', I have tried the 'measure area' function on the "attributes" toolbar, and i have tried fTools in ...
6
votes
2answers
13k views

Creating a circle with radius in metres

I am using shapely and Python. How should I go about creating a circle using shapely whose radius is in meters? If i use sampleCircle = Point(1,1).buffer(1) print sampleCircle.area This returns ...
4
votes
2answers
19k views

What are the units of the calculated area from a raster in decimal degree

I'm trying to calculate area for a raster file which contains 2 layers (0 for unsuitable habitat and 1 for suitable). It's been calculated successfully but I don't know what is the unit of the ...
3
votes
2answers
2k views

Determine density or cover from a raster layer that has been clipped by a polygon

I am a very new GIS user using ArcMap 10. I have a raster layer of tree canopy that I have clipped so that the layer is in a polygon that is a circle with a 2km radius. I have done this for four ...
3
votes
2answers
2k views

Calculating area by classified image in Earth Engine

I want to calculate the area for each classified color in earth engine. Here are my codes. var image = ee.Image(ee.ImageCollection('LANDSAT/LC8_L1T_TOA') .filterBounds(roi) .filterDate('2015-01-...
10
votes
2answers
3k views

QGIS area calculation differs when on the fly CRS transformation enabled

When I open QGIS, add the layer, and calculate the areas of the shapefile via field calculator I get a different area than when I open QGIS and check "Enable on the fly CRS transformation" and ...
7
votes
3answers
4k views

Calculating area of vegetation in raster file?

How do I calculate area of several vegetation types in a raster (.img file type) image. They are color coded. Am using QGIS (1.8.0) and ERDAS 9.2.
6
votes
2answers
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. ...
5
votes
1answer
8k views

Extending size (area) of raster using ArcGIS Desktop

My problem is that I would like to multiply two rasters using raster calculation tool. Both rasters have values 0 and 1, but the covered area of first raster is bigger (100 x 100 miles) then the area ...
5
votes
2answers
682 views

Calculating relative share of an area of circle that has slope >15% in Germany

I need to calculate the share of buildable land for the 15 major german cities within a 50 kilometer radius of the city center. Part 1 of the definition buildable is that the area must have a slope &...
4
votes
1answer
7k views

Convert area from square meters to degrees globally

I have a global raster file with 3600x1800 pixels. I don't have any information about the projection used. The raster contains one band with a quantity with the unit "per square meter". How can I ...
1
vote
1answer
616 views

How to aggregate values of different statistical areas that are overlapping?

Let's say I have one polygon layer counties with the polygons of administrative borders and another layer postal codes with the polygons of postal code areas. I have some statistical values per ...
1
vote
1answer
410 views

Calculate area intersected areas, problem [closed]

(I'm working in QuantamGIS) I intersected two layers creating a new layer. Within the attibute table of this new intersect layer i would like to calculate the new areas. However, it just doesn't ...
6
votes
1answer
211 views

$area gives NULL for some polygons in QGIS's Field Calculator

I have the map of Cambodia(map) and the economic land concessions(elc). In trying to find the proportion of district covered by land concesions, I need the area variable. But when I create the ...
5
votes
1answer
160 views

Calculating Statistics Based on Expression in QGIS?

Is it possible to calculate the sum of polygon areas based on whether or not it has a value in another column? For example: In column 2 I have the area of polygons. I want to calculate the area of ...
3
votes
3answers
1k views

Calculate the majority of one polygon in another (fishnet)

I am looking for a method to calculate the majority of one polygon file (a map of ecoregions) in a sampling grid (fishnet) in ArcGIS. The purpose is to assign each sampling grid (fishnet) to an ...
3
votes
3answers
17k views

Setting default units for Shape_Area to be Acres using ArcGIS Desktop

When I create a new feature layer polygon, how do I set the default in Shape_Area to read out in Acres?
3
votes
1answer
273 views

QGIS 2.6 summarizing area (m²) for current atributes

If I have a code for each polygon and I have counted the area in m² for each of them (all this information is in single columns). How can I summarize these areas by codes (for example summarize all ...
2
votes
4answers
6k views

Area of an irregular polygon using side lengths

I have only lengths for the sides of an irregular polygon, can anyone tell me how I can measure the area of the polygon? Remember only lengths of all the sides, no angles or coordinates. Few forums ...
2
votes
1answer
353 views

Error in area calculation

When I run the field calculator to update area, the resulting areas are too large. This happens whether I use QGIS 2.18 or QGIS 3.4. The default CRS is set to: ESPG:27700, OSGB 1936 / British ...
1
vote
1answer
143 views

Obtaining correct area values *With* correct projections? [duplicate]

I'm trying to get the percentage of each U.S. county overlaying groundwater (data from the census and USGS respectively). They're both polygons. I have 1) correctly projected the data and the layer (...
0
votes
2answers
2k views

Calculating polygon area within polygons in QGIS?

I am new to QGIS - I want to estimate the area of the reef under a polygon grid. My shapefiles are already in meters, however I am having a hard time calculating the area under the grid layer. ...
-1
votes
1answer
652 views

Adding Area column in Polygon layer using PyQGIS? [closed]

I have a WardBoundary.shp file with Polygon Features in it. I have to calculate the area of each Polygon and write into attribute Table. I can do manually by using '$area` but I need to automate ...