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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42 views

$area calculation doesn't work or wrong projection?

I've been reading the QGIS manual and I've encounter a problem I don't know what to do. I downloaded data from OpenStreetMap and the raster from http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp The ...
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1answer
121 views

Area Calculation incorrect

In ArcGIS 10.2 I created two buffers using the default settings one with a distance of 1 kilometer. When I calculated the area it has a square kilometer area of 3.14. All seems fine there to me. ...
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1answer
46 views

Limit Cartodb map to single geographic area

This should be really simple, but I've screwed up a map several times trying to figure it out and I'm working on a deadline, so I don't have any more time to play around with it. I just want to ...
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0answers
80 views

Area Calculations dont agree after raster to polygon conversion

I have a landsat 8 image [UTM 19s] (30m resolution, so 900m sq per pixel). I need to calculate the total area (hectares) from a land cover type. I take the count of pixels from the attribute table, ...
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0answers
36 views

Calculating % of Vegetation type burned by 0/1/2/3…fires in ArcGIS?

I am trying to plot the proportion of each of the major vegetation formations burnt by 1,2,3,4,5,6,7 etc fires (that is a frequency histogram of % of total area of that vegetation formation (e.g. ...
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1answer
216 views

Find the area of a map (Xkm x Ykm) from the left & right longitude and latitude

How can the area of a map from OpenStreetMap be determined in the form of Xkm x Ykm, given the following information: Left Longitude = 103.554879 Right Longitude = 103.740497 Top Latitude ...
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2answers
383 views

Deleting polygons smaller than certain dimension using ArcGIS for 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 ...
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1answer
64 views

Getting different values for area field calculations using ArcGIS Desktop?

We have self developed application based on ArcGIS 9.3.1 SP2. Our agents use that application to edit parcels. The parcel layer has a field SHAPE_AREA that is calculated by ArcGIS. Our application ...
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1answer
119 views

Only displaying polygons over certain size in ArcMap using Definition Query?

I have a polygon containing lots of bodies of water and only want to display the bodies of water over a certain size. Can I do this using a definition query?
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0answers
39 views

Clip feature according to its areas

I have a layer that has several overlapping areas (coming from CAD). So usually I do a "SORT" (tool), so I can view all the features. However, I wonder clip a shape according to their areas, it's ...
2
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0answers
40 views

Calculating the the area of overlapping polygons

In ArcGIS, I have a shapefile for a pipeline and another for plots of land that the pipeline shapefile touches and I was wondering if there is an obvious way to calculate the area that the pipeline ...
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0answers
65 views

Tabulate Area 2 Tool not returning correct area

I am having trouble with the output of the "Tabulate Area 2" tool in the following update: http://blogs.esri.com/esri/arcgis/2013/11/26/new-spatial-analyst-supplemental-tools-v1-3/ I have a layer of ...
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0answers
86 views

Is there a way to draw polygons with a fixed area?

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 ...
2
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1answer
376 views

How to calculate WGS84 (EPSG:4326) area in C# or SQLGeometry?

I am not normally a GIS developer, I am just helping out with a bug and I am stumped on what is going on here, could I get some help please. I have two calculations, one in 4326 (WGS84) and one in ...
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1answer
94 views

Calculate area above elevation threshold

I have a number of 95% isopleths (polygons) that represent animal home ranges. For each isopleth, I and want to calculate the Area (sq km) above 2000 meters. My initial thought was to create ...
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0answers
27 views

Common methods of area comparison?

I have a set of raster area results, that represent a prediction for a specific loccation. I would like to measure accuracy of two methods, given the actual values, estimate-A method values and ...
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1answer
59 views

how to get area in qgis 2.6.1 brighton?

I'm using QGIS 2.6.1 brighton, and I have a problem in computing the area of each layer. I was actually working on the map of our municipality and I would like to compute the total area of the ...
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0answers
70 views

How to calculate the area within a 4m clipped buffer derived from a raster

I am using QGIS 2.8.3. I started by classifying my area into habitat types using the semi-automatic classification plugin (SCP). Then I added points, and a 4m buffer around the points. So I could then ...
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1answer
47 views

How to use the hml <area> tag together with Openlayers 3 raster layers?

In order to include interaction to my Openlayer 3 raster layer, I would like to use something similar to the html <area> tag (http://www.w3schools.com/tags/tag_area.asp). The aim is to click on ...
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1answer
128 views

How to calculate overlap area of two polygons?

I am a beginner in the world of GIS. I have one table polygons with each polygon having north-east and south-west coordinates. And for every polygon, I need to find area of overlap with other ...
2
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1answer
167 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 ...
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1answer
80 views

How to get geodetic area? rgeos::gArea doesn't seem to work. Or area-preserving projection

I need to get an area of different polygons at continental scale (like third of Africa etc.). Usual functions like rgeos::gArea work only in the projection units. Is there any function which works ...
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2answers
87 views

How to measure the sum of the areas of each class in QGIS?

The project has a layer with several groups of polygons with different weights. Each group is associated to a weight. How can I get the sum of the area of each group?
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1answer
141 views

Routing Service that Avoids Areas?

I'm just starting with GIS, and I'm looking for a routing service that will allow me to avoid given regions on a map, or to build my own router that has this functionality. The site ...
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1answer
178 views

Variable width buffers depending on surface area (Arcmap 10.1)

I know this is a pretty basic question but I couldn't find the answer myself, so here I go: I need variable buffer widths depending on the surface area of the polygon (city) size. For example: A ...
3
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1answer
70 views

QGIS updated polygon areas

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 ...
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0answers
38 views

Z factor to get the results in square meters and cubic meters?

I have a DEM surface in WGS 1984.I want to calculate surface area and volume in different elevations.I wonder for example If I want to measure the area and volume below some height how shall I set the ...
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61 views

calculate Z~F from polygon and raster

I have a polygon shapefile and raster layer. How I can calculate the elevation and area (Z~F) relationship for each polygon by using QGIS or ArcMap?
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35 views

Clip only works on some areas, and not on others, despite being from the same dataset

I have a shapefile of provinces (nxprovincias), and another shapefile of small, disconnected areas ("protected areas") that overlaps with the provinces. I want to easily calculate the total area of ...
2
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1answer
126 views

Calculating area using dissolve and merge but getting shapefiles with empty attribute tables in QGIS?

I have a shapefile of a country with the 29 provinces. I also have shapefiles with the areas which are protected from construction (there are 4 categories for protection, within 4 shapefiles. Some of ...
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2answers
467 views

Polygon area calculation in Ruby (on Rails, rgeo, PostGIS and GEOS) in sqare meters

In a Ruby-on-Rails application, I need the area in square meters (or any other surface measure, be it ares, hectares, square kilometers, but not in pseudo surface measure like square degrees) of a ...
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1answer
472 views

Calculating Area of Intersecting Polygons and Buffers

SO, in QGIS I have several points with 1km buffers around them; some of the buffers overlap. Within the buffers are a number of ponds, which I have a shapefile for. I want to calculate the area of ...
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0answers
26 views

Forcing area calculation into miles in QGIS (without changing the PCS) [duplicate]

I'm working on an assignment that requires me to create an area column in miles without changing the projected coordinate system. ArcGIS has a tool that can do this ('Calculate Geometry')-- does QGIS ...
0
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1answer
40 views

Measuring watershed area using pixel accumulation?

I am doing watershed delineation at the continental scale using a GTOPO30 DEM, projected spatial reference WGS_WGS_1984_UTM_Zone_15N. Using Arc10.... My basic workflow using ArcHydro tools: Project ...
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0answers
18 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 ...
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2answers
387 views

Get Area size using Dragbox in Openlayers 3

I need to be able to show the square meters of an area using dragbox. There's a great example using draw polygon, but I need to limit users to a regular rectangle. The formulas and SHOULD be the ...
2
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2answers
218 views

R apply function in turn to each subset of a spatialPolygonsDataFrame

I'm trying to get the area of all the polygons in a SpatialPolygonsDataFrame: parcProj. library("rgeos") gArea(parcProj[2,]) works fine but: apply(parcProj,1,gArea) or ...
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1answer
90 views

Area and distance calculation/measurement unexpected after projecting? [duplicate]

I have converted a GIS shapefile of Botswana from the geographic coordinate system GCS_WGS_1984 to the projected coordinate system Africa_Albers_Equal_Area_Conic to be able to calculate the area of ...
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1answer
86 views

Calculating area of residential area wihin multiple ring buffer in ArcMap?

I need to calculate the size of residential area within 0-250m, 250-500m and 500-750m of a bus stop. I have made a multiple ring buffer around the bus stops. And I have a shapefile of the residential ...
3
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4answers
151 views

Calculate minimum area where x% of raster value total is concentrated within polygons

I have a raster layer (chlorophyll concentration) and a layer of non-overlapping polygons (regions of the ocean). For each polygon, I'd like to calculate the area where the majority of chlorophyll is ...
1
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1answer
803 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 ...
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1answer
100 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 ...
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1answer
135 views

QGIS problem calculating area

I have a problem with qgis 2.8.1 (Wien). Whenever I change the project SRC to WGS84-World Mercator (EPSG 3395), the area is calculated as zero. How can I solve this problem? Is this a known bug? The ...
1
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1answer
149 views

Algorithm to detect entity (aircraft, ship, etc) intrusion into geographic area

I have been tasked with coming up with an algorithm to determine whether or not an entity (aircraft, ship, etc) is inside or outside of a geographic area defined as a set of geodetic (lat/long) ...
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1answer
127 views

Use of Google Earth Pro derived area and perimeter for a thesis?

I have ground-truthing data of centroids for 23 sites and their surrounding land uses, but no money to purchase remotely sensed images of this remote region of Latina America. I would use the polygon ...
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1answer
130 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
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2answers
731 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 ...
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2answers
112 views

Find the area of points in PostGIS?

I have points that form a line. I would like to assign a radius to each point to give them volume, e.g. 50m and then find the area of the combined points. Does anyone know of a way to do this in ...
0
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1answer
170 views

Calculate area of a raster for an irregular polygon in PostGIS

I have a number of polygons with irregular shapes (i.e. non-rectangular) and want to calculate their areas after I have converted them to rasters. Here are my steps: Convert my geometry to a ...
3
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1answer
174 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 ...