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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25 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 ...
2
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2answers
60 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
30 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
76 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 ...
0
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1answer
27 views

UPDATE a value field for area of the geom and convert sq m to acres using cartodb

I'm trying to use the SQL commands in CartoDB to UPDATE a value field that shows total acres of the area of the_geom. My SQL is pretty poor/entry level and has some issues: UPDATE table_name SET ...
1
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0answers
31 views

Systematic inaccuracy in QGIS shape area

I’m trying to find out why I get different area figure in QGIS than in AutoCAD when I’m using the same shape file? What I did is I drew a shape in AutoCAD, imported it in QGIS and used the field ...
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0answers
17 views

Changing Area Output - PUMAS

I currently have shapefile of US PUMAS and another feature shape file (call it feature X). I am using arcpy to project both of these files to the following projection coordinate system (using ...
1
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2answers
60 views

Calculate area size within a buffer

I have a park polygons layer and a set of points which I gave a 1000m buffer. For each of them I had calculated the area size with calculate geometry. So with which tool could I calculate the size of ...
0
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0answers
27 views

Can I display customer addresses based on their address?

I have a CSV file with a lot of addresses of customers. Can I import this and it display a point on the address and all other information from the CSV for this entry? I want to display later in wich ...
1
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1answer
81 views

Calculate area weighted average of attribute in one layer by shape in another

For a project I am working on I would like to intersect fire station response districts with income data to determine the median income per response district. However the borders of the layers ...
0
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1answer
32 views

How to use Calculate Geometry tool to calculate area

I have added a field in my attribute table but I cannot calculate the area. The units field is greyed out and the options at the top say "area - disabled". What can I do about this?
2
votes
1answer
45 views

Create a grid with statistics of the merged shapefiles in QGIS

I operate with QGIS. I have to split the shape files of the buildings and the roads of a city into a grid of 500x500m per square and into each square I have to obtain the total free area, the total ...
3
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0answers
81 views

Why does field calculator compute area in square meters?

I am using EPSG:102748, and have set my Settings/Option preferred measurement units to ft. My CRS is NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet, and when I use the measure tool, it returns ...
4
votes
1answer
68 views

Equal area projections with different area results in ArcGIS for Desktop?

Using ArcGIS, I have to calculate areas of huge polygons all over the Pacific Oceans betwwen 20N and 30S. I have been trying different Equal-areas projections (Cylindrical and sinusoidal for example) ...
0
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0answers
57 views

Is it possible to calculate area of polygons from GPS points without POSTGIS

I am new with GIS. Assume we use the UTM30N coordinate system. Is it possible to calculate an area (say a square box) by the 4 given points? (assume the points are in order, and the coordinates are ...
1
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2answers
73 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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0answers
46 views

Using Tabulate Area 2 update for ArcGIS

I am trying to use 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 overlapping polygons in which ...
1
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0answers
63 views

Calculating vector area in QGIS

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 ...
0
votes
0answers
31 views

How can i perform area calculations in a raster file?

I would like to know if is possible and how can i calculate all areas or parts of it in one raster? Can i do it using the raster calculator? All help is appreciated, Best regards
3
votes
0answers
84 views

How to calculate areas in raster files

I got three files. The first is a shape file for country boundaries and the second and third are two raster files with the global land covers for 2005 and 2009. I'm thus encharged to calculate the ...
1
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3answers
95 views

Can I find out the exact areas which each category covers?

I have accessed a land use map and clipped the appropriate area I need to analyse. Is there a way I can find the exact areas which each category covers?
0
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1answer
23 views

Measuring roundness using buffers around centroids [duplicate]

I'm trying to measure the compactness (roundness) of some 800 polygons of different shape and size. I created the centroids and what I want to do now is to buffer those centroids with the exact same ...
0
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0answers
45 views

Unit of Geotools' getArea function

I have Polygons with WGS84/EPSG:4326 coordinates (like 13.57933804767844,52.5126298984133) and use the Polygon.getArea function to obtain the area of the polygon. But the result I get is something ...
4
votes
1answer
103 views

Comparing floor and roof areas using QGIS?

I am pretty new in this GIS topic and I would really appreciate if someone can help me with this problem. I am doing a research for university that shall show the available roof area for ...
2
votes
1answer
81 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)) ...
8
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2answers
230 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 ...
4
votes
1answer
91 views

Routing ensuring all areas are touched

I'm making a web application with leaflet and OSM. It's all going well, but now I need a little help. I'm searching for a good routing engine, that's capable of creating the most probably taken route ...
0
votes
1answer
111 views

Converting area of a polygon from steradians to square kilometers using D3.js?

How can I find the area of a polygon in square km using D3.js? I'm not even really sure whether to use d3.geo.path.area or d3.geo.area. Here is my code (JSFiddle): var d = { "type":"Feature", ...
3
votes
1answer
90 views

Thiessen Polygon Total Area Calculations Model Builder/Python Code

I am attempting to create a tool using Model Builder (and Python code) for calculating the average annual precipitation of a study area using the Thiessen Polygon Method. My model runs good other than ...
1
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1answer
43 views

Is product purchaser in distribution area?

I am going to be using PostGIS 2 to create a lookup service. Given a point (lat/lon), I need to either find if a product can be distributed there, or b) a list of products or distributors. I am ...
3
votes
0answers
73 views

Why do each of my buffer-polygons have different areas

I`m using Qgis 2.2 and 2.4 and loaded a wms-map using the coordinate system ERTS89 UTM 32N. I set 8 points (all in on shp-fileand in UTM 32N) on various locations on the map. After that i created a ...
0
votes
1answer
97 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 ...
0
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0answers
84 views

Dividing a polygon into certain areas (open source solution preferred)

I have a polygon with an area of 50.000m². Now i want to devide this area in two polygons of different areas with a line layer. The left polygon should have an area of 30.000m² and the right polygon ...
0
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1answer
38 views

largest area polygon

I have a layer of polygon shapes, I know this could be a quite easy question to answer but I am a beginner and probably I am not using the right concept or terminology when looking at the desktop help ...
0
votes
1answer
52 views

How do I measure the area difference between polygons in different shp files?

I have couple if shp files with 1000 polygons scattered in them (around 1k in each file) , each shp file represents a time frame (3 months period) and I want to show the a report with a progress of ...
-1
votes
1answer
68 views

creating circle with radius in metres

I am using shapely and python. How should I go about creating a circle using shapely whose radius is in meters? If i use sampleCircle = Point(1,1).buffer(1) print sampleCircle.area This returns an ...
3
votes
0answers
63 views

What is the area that OGR extracts from the (geometry) shp files for polygons?

The ESRI July 1998 technical documentation for polygon shapefiles at page 10 makes no mention of either area measures or length measures (apart from byte/record-layout matters). Yet OGR enables me to ...
2
votes
2answers
158 views

Python Add-in- Message Box to display area of selected polygons

I am looking to create a Python AddIn which calculates the area of selected polygons. I would like to be able to select the features, click a button on the toolbar, and a Message box displays the sum ...
2
votes
1answer
72 views

Prior art on rhumb line and great ellipse areas?

I'm adding the computation of the area betweeen a rhumb line or a great ellipse and the equator to GeographicLib. My formulations are briefly given in here and here. These formulations are similar ...
2
votes
1answer
145 views

Calculating area of polygon inside region?

I am new to geographic information systems and i need to calculate the area of a a polygon ( a circle to be precise) that falls inside the boundaries of a region, say a state or a country. For ...
3
votes
0answers
114 views

Calculating length of road network within a polygon [duplicate]

I have a road network stored in a gdb and some polygons in another gdb. I want to populate an attribute for each polygon with the total length (in km) of the road network that it overlaps. Any idea ...
1
vote
2answers
197 views

Calculate area inside polygons based on slope

I have some DEMs and have computed the slope in degrees for each one. I have also classified the slope raster into the following 5 classes: 0-3, 3-15, 15-35, 35-50, >50. What I want to do is to ...
1
vote
1answer
39 views

Looking for a complete list of cities by state, with area code

Our company is working on moving our sales assignments from area codes to ZIP codes, and we need some kind of dataset to help move existing assignments to the new system. Does anyone here know where ...
3
votes
1answer
106 views

Trouble calculating areas in QGIS using field calculator

I am testing various projections to calculate areas using ICES statistical shapefiles and the QGIS field calculator. I am using ICES areas downloadable from the following link: ...
1
vote
2answers
229 views

How to validate OpenLayers area calculation using PostGIS?

I am working on a GIS API that work on top of OpenLayers. I have a feature that calculates the area of a drawn polygon. I have tested it on the browser and the areas I got, appear to be correct. For ...
2
votes
3answers
121 views

Summarize the total area of land use polygons within map sheets - how?

I would imagine that at least some of you have encountered similar problems to mine and I´d like to hear how you solved them. I have a map sheet index (a grid as a shape file) covering a large area. ...
0
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0answers
37 views

Pros and Cons of a latitude adjustment grid vs other methods of area calculations

When working with high resolution global raster data in WGS 1984 I often need to calculate areas. Now the traditional way for me to achieve this has been to reproject the data to an equal area ...
2
votes
1answer
462 views

Calculating geometry area in ArcGIS for Desktop using ArcPy?

I have a polygon shapefile and I want to write a Python script to add a field named "area" and calculate its geometry areas. The script is like this: ...
2
votes
2answers
148 views

How to calculate area of shapefile with a merged layer

so i have 'save as''d the new project and layer with my new Custom CRS project string being '+proj=laea +lat_0=70 +lon_0=0 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs'. ...
2
votes
3answers
290 views

How to figure out the unit of measurement from table fields?

I have a couple of fields with predefined values. In particular I have an 'area' field that I need to figure out its unit of measurement (e.g. km, miles, acres). What's the easiest way to do this?