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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1answer
27 views

Calculate area for each polygon in R

I am working with a shapefile that has many polygons. How do I add one more field named "area_sqkm" and calculate area for each polygon in the shapefile?
0
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0answers
24 views

QGIS area calculation [duplicate]

When I calculate an area with area measure in QGis, it gives as a result values of area 44% more area than in reality, any idea why?
0
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1answer
36 views

Percentage Coverage

I know pretty much nothing about GIS. I'm learning as I go on arcgis. I have a shapefile of US counties for which I have calculated the county area in square miles (called CountySize). I also have a ...
0
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0answers
12 views

Tabulate Area Error: Range exceeds 100000 and number of unique values exceeds 500

I've been trying to use the 'Tabulate Area' tool to calculate the area of different land cover types in 1km grid cells in the UK. I've received 2 errors, Value range for ... exceeds 100000 and number ...
-1
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2answers
71 views

ST_DWithin matches wrong points

The following query crosses every city called "London" with every "place" (both of which are in London, UK) and calculates the distance. The points are of type geography. SELECT c."Name", ...
1
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1answer
43 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 ...
0
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0answers
27 views

How to calculate area of water body after calculating NDWI in arcgis 10.1?

I have calculated NDWI value of my Landsat image 5 TM. I have also corrected my image for TOA Reflectance. Now I want to calculate the area of water body of my region.It will be very helpful for me if ...
2
votes
2answers
63 views

Mistake in Calculating Area or a Bug in QGIS? [duplicate]

I am trying to calculate the area of a polygon following the step by step mentioned in all the questions related to this issues in this website. Nonetheless, the result of the area calculation is ...
3
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4answers
132 views

Tool to delete too many points in one area, ArcGIS, ArcMap

I have two layers: points and areas (buildings). In many places I have two or three points in one building. I would like to leave only one point in one building. How can I do that?
3
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1answer
67 views

How to Add Name of Different Category in Attribute Table

I'm stuck in a problem when I started calculating area in arcmap 10.1. In the picture, I categorize my polygon into four unique labels - i.e. vegetation, sand fill, water body, built-up area. Now I ...
-1
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2answers
29 views

How to use Landsat 8 or MODIS products to classify land area

Anyone know of a good tutorial where I can learn how to use satellite vegetation imagery from Landsat or MODIS to classify which crops are grown where over time for a West african country. I don't ...
1
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1answer
60 views

Get regions containing a coordinate in Overpass-API

I am using the Overpass-API to access OSM data. I want to retrieve all relations or ways (don't really know which of them, since I'm very new to this...) containing a given coordinate. I thought of ...
0
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0answers
35 views

Subdivide (split/cut) polygons or raster (e.g. based on area, neighborhood or “bottlenecks”)

I'm looking for a way to cut/separate my polygon (or raster) shapes at the respective thinnest region (as indicated by the red lines in the image). However, this should only be done for areas above a ...
0
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0answers
17 views

Adding data labels of Polygon Areas directly to ArcMap?

I need to know whether it's possible to add data labels of polygon area sizes directly to the map and how to do this? I have area data for about 38 polygons, and the distance between each (this is ...
0
votes
1answer
40 views

Arcgis FeatureLayer.MODE_ONDEMAND not select exactly coodinate?

I'm working with ArcGis API. I push my Feature Layer on map in MODE_ONDEMAND. But when I select feature (selectTask), the coordinates come out as [692010, 101011], with no decimal places. What I want ...
0
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2answers
44 views

Calculating area of polygon within square mile in ArcGIS?

I would like to create a raster, where in every cell it returns the area of land in a polygon feature. So for example, every cell in the raster would give park land per square mile, or vacant land ...
1
vote
2answers
64 views

Calculating relative share of area covered by water/percentage of polygon area that overlaps in ArcGIS for Desktop?

I need to calculate the share of the area within a 50km radius of major German city centers that is covered by water with either Arcmap 10.3.1 or Qgis 2.14. My plan is to use the Global Lakes and ...
3
votes
2answers
45 views

Tiny difference of calculated area of polygons

I have a shapefile of about 62.000 polygons. I calculate the area of each polygon on a field, named AREA1, with Calculate Geometry option. Secondly, I create a new field field named AREA2. I calculate ...
2
votes
1answer
36 views

Area calculations using a layer in a projected data frame versus a projected feature class in ArcGIS

So I've been tasked with automating a formerly manual process in model builder in which I'm trying to calculate land area. In the former manual process the feature class was brought into ArcMap and ...
0
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0answers
10 views

Allocating premises between postcode polygons and telephone exchange area polygons in QGIS?

I have telephone exchange areas as one polygon layer and postcode (codepoint) polygons as another. The postcode polygons have the number of premises in each postcode as a field. I want to estimate the ...
2
votes
0answers
55 views

Size of an object in raster image based on DPI resolution and number of pixels

I'm trying to estimate the size of an object in a raster image, with known DPI resolution. To evaluate the validity of this method, I do as follows: 1) I'm drawing a 0,02 in × 0,02 in black square ...
0
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0answers
20 views

Why do area calculations of OSM polygon shapefiles return negative values in ArcMap?

Whenever I tried to calculate the area of polygon shapefiles (OSM, Geofabrik) part of the polygons have negative values. All values appear to be right except the fact that around half of them are ...
1
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2answers
23 views

Over-calculation of area due to parcels occupying same space

I'm trying to get the total acreage of different parcels by land use, and unfortunately I keep getting a total of ~15000 acres instead of ~12000 because it's over-calculating the area where there are ...
-2
votes
1answer
29 views

Select Adjacent Tax Parcels by Area

I am trying to select for adjacent tax parcels where their total area would be close to a specific value (450 acres). Area is already an attribute of each parcel. ArcGIS v. 10.3.1 Unfamiliar with ...
3
votes
2answers
105 views

How to calculate the relative share of an area of a circle that has a 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 &...
0
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0answers
19 views

Finding measuring units [duplicate]

Every time I perform the geoprocessing tools buffer or intersect, my layer gains two more attribute columns, named "Shape_Leng" and "Shape_Area". How can I know in which measuring units are these ...
0
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2answers
46 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.
1
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0answers
28 views

how to calculate area if it is falling in two utm zones [duplicate]

I am using ArcGIS 10.1. How do I calculate an accurate area measure for a polygon, where portions of it are falling in two zones, i.e. UTM ZONE 44 & 45 (India)?
2
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0answers
42 views

Calculating Area for data in WGS 84 using ArcGIS for Desktop? [duplicate]

I am using ArcGIS 10.1.1 for Desktop on my laptop. When I try to calculate the area in WGS 1984 the area is disabled. If I work in one projection, say WGS 1984, and calculate area in another ...
2
votes
1answer
57 views

Area biased in 1x1 km2 vector grid in QGIS

I used Vector -> Research tools -> Vector grid with enabling Output grid as polygons to create a 1000 by 1000 m grid from a shapefile. However, when I calculate the area of each grid cell ...
0
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0answers
47 views

How to scale polygon to obtain specific area in javascript?

I have got a source polygon (saved as standard js array). I want to scale it down to obtain new destination polygon in the centre with 1/3 of source area. On the cartesian space i just scaling down ...
3
votes
1answer
113 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
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0answers
53 views

Dividing a shape in equal pieces?

I have data in Autocad. As you can see there's a buffer (purple) inside of the blue shape, I want to divide the blue shape to small equal pieces that have the same surface area. What I'm looking for ...
0
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0answers
46 views

calculate area using pixel count (ArcMap)

I have been trying to research solutions and solve my problem for a while now, without success. I have a raster file with 2 layers, namely 0 and 1. My attribute table includes the pixel count for ...
0
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2answers
73 views

QGIS NDVI Spatial Analysis

I have an NDVI raster that I would like to reclassify into some arbitrary bins i.e. all values between 0 - 0.2, 0.2 - 0.4 etc. for spatial analysis. Could anyone advise how to: 1) reclassify a ...
3
votes
1answer
82 views

Calculate area of geometry derived from current feature in QGIS 2.8

I'm trying to create a new field defined as the area of the convex hull of the current feature, in the Field Calculator in QGIS 2.8. Calculating the area of the current feature is easy ($area), and ...
2
votes
1answer
143 views

How to calculate marker area on OpenLayers 3?

I have the following scenario: a polygon (or few) and a marker which is displaying some data of its related geometry/ies: What I want is to manage the map's zoom level in order to decrease the ...
0
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0answers
29 views

Trouble with Calculate Geometry in ArcMap 10.2? [duplicate]

I got a "Federal Lands" shapefile from nationalmap.gov. I clipped it down to the geography I am focusing on (a few counties in eastern California). I am trying to use the "calculate geometry" tool to ...
1
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0answers
38 views

Calculate obstacle accountability area in QGIS

Still being new to the whole GIS world, I am trying to calculate a regulatory takeoff obstacle accountability area for a given runway. For my case, this is defined as an area as follows. At the start ...
3
votes
2answers
69 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 ...
1
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0answers
40 views

QGIS Modeler different results by calculate the $area

When I use the graphic modeler,add a field and calculate the area, the sum of the area of all records is different to result which I get by calculation in the fieldcalculator. The result in the ...
-2
votes
1answer
46 views

How to determine area from polygon? [closed]

I have to digitize one polygon that can accommodate 10million.cubic metre of waste and the study area is completely flat surface. How to determine area?
0
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1answer
18 views

calculating ratio of areas on a sphere

I have 2 shapefiles and after identifying their intersections I'd like to know the ratio of intersecting areas, e.g. a given shape S in file1 intersects with shapes (x1,...,xn) in file2 with ?...
1
vote
1answer
34 views

Area estimation using raster image

I have a map of trace gas (NO2) distribution over big cities and other anthropogenic objects. The purpose is to estimate the area of distribution. I attached the sample image to illustrate what I do. ...
3
votes
0answers
55 views

Wrong area using Albers Equal Area Projection in GRASS for Java, Indonesia

I am just getting to know GRASS 7.0 and I am struggling finding a good projection to work on a spatial analysis of Java, Indonesia. I am new to the forum, so if information's are missing for a better ...
8
votes
1answer
287 views

Circle area calculation in QGIS is inaccurate

I created a circle with a radius of 3 km, calculated the area using field calculator and got a different result from real area. The QGIS result is 28273078.8 while manually calculated area is ...
1
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0answers
91 views

Projecting GeoJSON polygon object in python to calculate area

I have a script, written in python, that does many calculations - but one set of calculations hinges on determining the area of a polygon that I read in, in GeoJSON format. I can convert this object ...
1
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1answer
78 views

Calculate total coverage of circles on map with PostGIS

I am trying to calculate the total area covered by c.a. 400 Circles of diameter 15Km. The centers of these circles are stored in a column of type geometry:4326 in my database. Some circles overlap, ...
0
votes
1answer
43 views

how to calculate polygon area using field calculator QGIS? [duplicate]

I am trying to calculate the areas of some polygons and i want to use the field calculator to measure the area. The result i got using this method is different from using the QGIS measurement tool. I ...
0
votes
2answers
150 views

How to determine objects area (size) measurement error using satellite images?

I am working at scientific paper about measuring object's size (it's area) using satellite images. I got some progress in it and need to compare my results with other scientific works. I have found ...