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
33 views

How to determine area from polygon? [on hold]

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
14 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
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1answer
31 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
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0answers
44 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
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1answer
254 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
32 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
48 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
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1answer
24 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
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2answers
84 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 ...
1
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0answers
30 views

Identifying Open Areas in OpenStreetMap?

I am currently creating a system using OpenStreetMap (OSM) and I need to identify open areas in the map. I know there are existing open areas on OSM but is there a way to identify more open areas ...
1
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1answer
55 views

Finding the area of polygons within other polygons in R

Is there a function in R which will loop through a layer of zonal polygons (i.e. a polygon grid) and return the area of a second polygon layer that is contained in each grid cell? I have a layer of ...
0
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0answers
9 views

How to calculate area percentage from polygons from one shapefile within another? [duplicate]

I'm working on a project where I have to create python code that takes land-use data and adds a percentage field for each land-use category in a Census Tract shapefile. I've been trying to work with ...
0
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0answers
22 views

What is the right projection for area calculation in Kenya? [duplicate]

I want to calculate the area of counties (1st admin level) in Kenya in ArcGIS. What is the right projection for that? I know I should use an equal area projection, but when I use them (I tried six ...
1
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1answer
34 views

Summarizing areas of features of multiple classes

I am conducting a buffer analysis on a vector feature class of Urban-Wildland Interface zones, and am trying to calculate the total areas of each particular classification of interface area. As I ...
0
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1answer
52 views

How can I draw a polygon with a fixed area in ArcMap

Is there a way to draw a polygon with a fixed area in ArcMap? For example, I'm trying to create a 40,000 foot boundary around a feature, but the boundary does not have to be any specific length or ...
1
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1answer
28 views

How to calculate areas for data that covers the whole of Australia [duplicate]

I have a polygon shapefile showing mining areas across all of Australia. I want to calculate the area for each of the polygons however they have been provided in a Geographic Coordinate System ...
1
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2answers
40 views

What data projection should I use for area analyses in different countries at a global scale

I'm creating A4 maps to show where forest cover and mining fields overlap across the globe. Each A4 map focuses on a specific country (e.g. India, USA, China, Australia...). For each country, I need ...
0
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2answers
29 views

I have a land cover vector dataset, and would like to calculate the area of each land cover in ARC, how can this be achieved?

My land cover vector 25m data includes land cover types such as 'Broadleaved woodland' and 'urban'. I have cropped the dataset down to my study area and would like to calculate the area of each land ...
1
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1answer
53 views

Show groups of coordinates on a map, to visually find coordinates that belong to the wrong group

I have a (very) long list of casinos. Each casino has: latitude longitude boss (a single boss runs from 1 to 50 casinos) Sample: 40.642 -73.997 Freddy Queens 40.680 -73.985 Freddy Queens 40.697 ...
0
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2answers
61 views

Area calculation of mapped categories in ArcGIS 10.1 Basic

I have performed supervised classification (Interactive supervised classification and Maximum Likelihood Classification) on landsat reflectance raster data to classify it into seven land use ...
1
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1answer
54 views

How does ST_Area in PostGIS work?

I am performing a simple calculation on a polygon known to be approximately 6226 km^2 in area. It is stored in a Geography (WGS84 SRID) column. The query is: select st_astext(col), st_area(col) area ...
0
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1answer
41 views

Creating polygon features on scanned historical maps to measure areas in ArcMap?

I have a collection of historical scanned topographic maps from the 19th century that have already been georeferenced (NAD 1927). I'm uploading the maps as JPGs into ArcMap and would like to use the ...
1
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0answers
41 views

problem with area calculation in QGIS

I encountered a problem in QGIS 2.10.1 when I tried to calculate the areas of polygons in a polygon layer. I followed the instructions here ...
0
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1answer
30 views

What is most accurate Spatial reference system for calculate Area entire world [duplicate]

I want to know what Spatial reference system is most accurate to calculate area? I want to use it for entire world (-180,+180,-90,+90 area in WGS84 system) I have every thing ok I only need to ...
1
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1answer
32 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 ...
1
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1answer
86 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. ...
2
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1answer
39 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 ...
2
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0answers
67 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, ...
0
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0answers
35 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. ...
1
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1answer
145 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 ...
6
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2answers
268 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 ...
1
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1answer
54 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 ...
1
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1answer
92 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?
2
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0answers
37 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
28 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 ...
1
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0answers
39 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 ...
2
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0answers
68 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
228 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 ...
0
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1answer
58 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 ...
0
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0answers
26 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 ...
1
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1answer
51 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 ...
2
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0answers
57 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 ...
0
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1answer
39 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 ...
1
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1answer
97 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
votes
1answer
114 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 ...
1
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1answer
47 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 ...
0
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2answers
60 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?
1
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1answer
119 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 ...
1
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1answer
116 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 ...
2
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1answer
54 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 ...