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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Calculating 3d polygons' surface area using ArcGIS for 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 ...
2
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2answers
580 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 ...
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1answer
28 views

How do I sum up polygons in each squared grid in QGIS?

So I have created a square grid (fishnets) layers with another layer of Philippine mangrove distribution polygons, I intersected two layers so the Area1 (philipine mangrove polygons) and Area2 (square ...
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0answers
24 views

Property “Area” not an option in Calculate Geometry

I want to calculate the area of a shapefile, but I the "area" property does not show up when I am in the "calculate geometry". Here is what I have done so far: I took a tracklog, used "points to line" ...
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1answer
160 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 OpenRouteService....
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1answer
305 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 (...
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1answer
224 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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1answer
22 views

Are degree based length/area measures comparable across regions?

I have global shp files of basins (polygons) and rivers (lines). I wish to calculate a measure of stream length per basin area. It should be comparable across world regions, e.g. I wish to compare ...
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1answer
23 views

Area measurement with out geodesic in openlayers3

<!DOCTYPE html> <html> <head> <title>Measure example</title> <!--<script src="https://code.jquery.com/jquery-1.11.2.min.js"></script>--> <script src="...
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3answers
32 views

Calculating the area of polygons within bigger polygons

I work with PostGreSQL and have 2 tables, both in EPSG 2950: Table 1 has a couple of big polygons and table 2 has smaller polygons that INTERSECTS with the polygons of table 1. I am looking for a ...
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1answer
182 views

Getting wrong value for area of geometry using Spatialite?

I am trying to implement a measuring tool on apple maps for IPAD. As a part of that i collect all the touch points on the map into an array and constructing a geometry object from that and then ...
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0answers
11 views

Udacity Google Maps API Course: an event listner causing map to dissappear

I'm making my way through the Google Maps APIs course on Udacity (its free btw) and am stuck on the Drawing and Geometry Quiz: Using an event listener on a polygon completion event, add a feature that ...
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0answers
12 views

Calculate Worldwide Raster area (30arcsec, WGS198) [duplicate]

I have a worldwide raster dataset (30 arcsec, WGS1984) with 11 Landcover classes. My goal is to calculate the extension for each class. I´m using ArcMap 10.1.3. So far I projected my Raster in ...
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2answers
491 views

Is it possible to have auto-updating area fields?

I'm using QGIS 2.4.0 and I've noticed some problems with the derived area and the $area field. Firstly, I have a polygon which is a filled ring, inside another polygon. The derived area, and therefore ...
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1answer
56 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?
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0answers
26 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?
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1answer
39 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 ...
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2answers
78 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", ...
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0answers
13 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 ...
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1answer
51 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 ...
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0answers
35 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 ...
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0answers
129 views

Calculating vector area in QGIS? [closed]

I have calculated a viewshed (ZVI) in OpenWind and opened the raster in QGIS I have then converted the raster to a vector When I open the attribute table there are 4682 rows (features) and there is ...
4
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2answers
778 views

How to compute area in acres in QGIS?

I am new to QGIS. I am creating a shapefile that will have several polygons. I need to have a column in the attribute table that will show the acres of each polygon. I have successfully done this but ...
2
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1answer
2k views

How to read the area column in QGIS?

I have few problems understanding how units are managed in QGIS. According to the area column I created for a shapefile, the area of a shape is 0.7727... I just checked on Wikipedia and indeed the ...
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1answer
7k 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 ...
2
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2answers
64 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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1answer
131 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 ...
7
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3answers
2k 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.
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2answers
2k 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?
3
votes
3answers
16k 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 ...
3
votes
4answers
138 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
68 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 ...
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2answers
47 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 ...
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2answers
39 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
68 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 ...
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0answers
39 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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1answer
42 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 ...
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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 ...
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1answer
140 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?
8
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2answers
591 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 ...
3
votes
2answers
46 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 ...
9
votes
7answers
11k 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. ...
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2answers
75 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 ...
2
votes
1answer
38 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 ...
3
votes
2answers
681 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)) ...
2
votes
0answers
57 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 ...
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0answers
22 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 ...
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2answers
25 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 ...
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votes
1answer
32 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 ...