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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2
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2answers
328 views

Tabulate Area in ArcGIS for Desktop not creating correct output?

I have used the Tabulate Area zonal spatial analyst tool in ArcGIS many times, and am encountering a problem for the first time. I am using a polygon grid (fishnet) as my zone dataset, and tabulating ...
4
votes
3answers
745 views

Remove Holes Existing Within a Single Polygon for a specific area in Qgis

I have a shapefile that consists of a single polygon. I have gaps within the polygon that needs to be eliminated, but only the ones that are less than 200m2. I tried different ways but none of them ...
0
votes
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 ...
0
votes
0answers
28 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 ...
0
votes
0answers
23 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 ...
1
vote
2answers
32 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 ...
-2
votes
1answer
35 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
votes
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
vote
1answer
223 views

Calculate tree cover over certain area from raster data

Last year Hansen et al. published Global Forest Change map as set of raster data available in TIFF format. Basically those are 30-meters resolution satellite images with pixel values ranging from 0 ...
3
votes
2answers
836 views

How calculate areas between certain contour lines in qgis? [closed]

How do I calculate the area between certain contour lines (e.g. 0-800, 800-1400, 1400-2100...) from a given shape file. What I need is the area of the the certain elevational levels. shape file is ...
1
vote
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. ...
2
votes
1answer
3k views

Dissolving two different buffers together so not overlapping using ArcGIS Desktop?

I am trying to find out how many registered sex offenders live within 2,000 feet of a school/park in a specific county. The park buffer and school buffer are dissolved but not together. I am also ...
8
votes
1answer
255 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 ...
3
votes
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 ...
9
votes
6answers
9k views

How to remove 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. ...
1
vote
0answers
33 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
vote
1answer
49 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
26 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
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
vote
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
vote
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 ...
6
votes
2answers
272 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
vote
3answers
7k 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 ...
1
vote
0answers
10 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
votes
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
vote
1answer
35 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
votes
1answer
55 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
vote
2answers
343 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 ...
1
vote
2answers
41 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 ...
1
vote
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 ...
0
votes
2answers
30 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
vote
1answer
56 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
votes
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
vote
1answer
55 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
votes
1answer
46 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
vote
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 ...
2
votes
1answer
40 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 ...
0
votes
1answer
32 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
vote
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
vote
1answer
87 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
votes
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
votes
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. ...
0
votes
0answers
398 views

How can I calculate raster cell area for upslope contributing area

I am new to spatial analysis, and trying to follow this tutorial to generate a topographic wetness index for my area of interest: ...
1
vote
1answer
94 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?
3
votes
2answers
311 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)) ...
1
vote
1answer
154 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 ...
1
vote
3answers
608 views

Calculating new shapefile areas after clipping using ArcGIS for Desktop?

I'm working with the WWF ecoregions, which use the GCS_WGS_1984 geographic coordinate system. I have clipped the ecoregions with a species range (consisting of two polygons), but the new attribute ...
1
vote
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 ...
2
votes
0answers
38 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
votes
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 ...