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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57 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 ...
3
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81 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 ...
3
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0answers
351 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 ...
3
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185 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 ...
3
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0answers
108 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 ...
3
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182 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 ...
3
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699 views

Extract values from raster based on weighted average area using polygon grid

EDIT: I am using Armap 10 sp 5 I have found similar questions but they were either unanswered or somewhat different to what I am asking. I have a raster with cell values 1-5 and a polygon shape file ...
3
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134 views

Reshaping polygons while preserving area

I'm looking to manually skew the shapes of areal polygons, but need to ensure their areas are not altered. Is anyone aware of any GIS tools or programming workflows that exist for manually reshaping ...
3
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378 views

Getting coordinates of pixels

I want to compute an area of certain object on a picture using Monte Carlo method. The picture shows some shape on white background. To do so I figured out that I'd get the coordinates of non-white ...
3
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146 views

GeoTools, add column in query with CQL

I'm trying to query the database (DataStore) and want to let the datastore calculate a value for me. In SQL I would do it like this: SELECT name, ST_Area(ST_Intersection(the_geom, ....) AS myValue ...
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58 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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89 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
40 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
47 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 ...
2
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0answers
93 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 ...
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272 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 ...
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0answers
32 views

Why outside border of a service area is always not reasonable?

In ARCGIS 10.1 network analysis, why results of service area are different if number of break points is changed? For example, the grid is 300m*300m, I try to produce service area around a node. ...
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0answers
1k views

Projecting a Raster from WGS84 to planar Equal Area to Calculate Area: How to Select the Cell Size?

I have a broad question on how to calculate the 'correct' cell size for a raster when analyzing an area not at the equator. My goal is to project a land cover raster provided in GCS WGS84 to an equal ...
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0answers
92 views

Determining homogenous blocks of individual tree species in a woodland, and creating a new shapefile without blocks/polygons of < minimum area?

I'm working on a project attempting to identify suitable woodland habitat for red squirrel translocation wherein conservation efforts could be focused. Below is a small section of the map showing ...
2
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0answers
132 views

Raster area (QGIS) problem explained

I would like to know the area that each value in a raster has... The raster I have has values from 2-15 and I would like to know the area that each value is occupaying within my polygon... Thanks! I ...
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0answers
960 views

How to calculate the area of a polygon considering the relief?

I work in a fire department and i'm mapping all the fires that occur in my area, creating polygons that represent burnt areas. my problem is that the values are not accurate... for instance, arcgis ...
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38 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 ...
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40 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 ...
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101 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 ...
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31 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 ...
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74 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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41 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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62 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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37 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 ...
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0answers
52 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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22 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 ...
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241 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 ...
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0answers
130 views

How to calculate the area of overlapping buffers within a single layer

I am very new to GIS, so don't know if this is EXTREMELY easy or impossible. I have GPS coordinates for stores (about 15000) for which I have created a buffer zone around each store location ...
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145 views

Problem with service area gap with Network Analyst

I am working on running Network Analyst to create a Service Area from a single location to all around it. Esri's network dataset was missing a couple crucial street lines, and so I uploading their ...
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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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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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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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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 ...
0
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0answers
40 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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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 ...
0
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0answers
11 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 ...
0
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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 ...
0
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0answers
53 views

How to scale polygon to obtain specific area in javascript?

I have got a source polygon (saved as standard js array). I want to scale it down to obtain new destination polygon in the centre with 1/3 of source area. On the cartesian space i just scaling down ...
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53 views

Dividing a shape in equal pieces?

I have data in Autocad. As you can see there's a buffer (purple) inside of the blue shape, I want to divide the blue shape to small equal pieces that have the same surface area. What I'm looking for ...
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49 views

calculate area using pixel count (ArcMap)

I have been trying to research solutions and solve my problem for a while now, without success. I have a raster file with 2 layers, namely 0 and 1. My attribute table includes the pixel count for ...
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0answers
39 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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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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0answers
42 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 ...
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0answers
394 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 ...
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0answers
128 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 ...