Area is a quantity that expresses the extent of a two-dimensional surface or shape, or planar lamina, in the plane.

learn more… | top users | synonyms

2
votes
1answer
48 views

Defining projection, reprojecting, and wrong area values [duplicate]

Apologies for duplication--this was mentioned in a previous post, but was suggested that this specific problem should be posted separately. My data: http://water.usgs.gov/GIS/dsdl/aquifrp025.tar.gz ...
0
votes
1answer
44 views

Cannot obtain correct area values *With* correct projections

I'm trying to get the percentage of each U.S. county overlaying groundwater (data from the census and USGS respectively). They're both polygons. I have 1) correctly projected the data and the layer ...
0
votes
1answer
57 views

QGIS: Multiply Raster Value with Pixel size

i'm working on a map with population densities. My raster data contains values as [People/square meter] for each cell. I have per capita values of energy demand etc. which I want to multiply with the ...
0
votes
1answer
27 views

Calculating Area of Raster Classes

I have a raster in a GRID format that was created by Image Classification. The GRID is projected in StatePlane meters, but I would like the area in square feet. I'm assuming I will need to use the ...
2
votes
1answer
70 views

Calculate population coverage

I am relatively new to QGIS and hope I explain this right. I am looking at the percentage of an population that has geographical access to healthcare. Therefore I have one shapefile with village ...
0
votes
3answers
57 views

Same size polygons giving different overall areas

I am currently working with multiple shape files that I have clipped to the exact same extent, but when I calculate area (acres) within each polygon. I am getting different results between the ...
0
votes
1answer
62 views

Determining if a Geodetic location is inside a polygon made up of Geodetic vertices

Suppose we have a polygon with Geotic vertices (Points A through E). Is there an algorithm that I can use that could determine If F is inside of it? In addition, what is the most efficient way to ...
0
votes
1answer
45 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 ...
0
votes
1answer
28 views

Difference in vector / raster area measurements

I'm comparing raster and vector distance zones. So I created a line, calculated the Euclidean distance, and reclassified the raster to two zones: from 0-10m and 10-20m. To compare it with vector ...
1
vote
0answers
34 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 ...
1
vote
2answers
123 views

Setting default units for Shape_Area to be Acres using ArcGIS Desktop 10.0

When I create a new feature layer polygon, how do I set the default in Shape_Area to read out in Acres? I am using ArcGIS Desktop 10.0.
0
votes
1answer
35 views

How to select a specific area (in a polygon form) determined by some value range in a raster band?

For example, I want create a vector layer with polygons that represents all areas where the elevation is between 500 and 600. Someone has any idea to help me? I'm using PyQgis 2.2.
0
votes
0answers
18 views

How to calculate area of lat/lon rectangle? [duplicate]

(Strange that this Q seems to be unanswered...) Given a rectangle like this, say (from Java, but that should be immaterial): double minlat; double maxlat; double minlon; double maxlon; How to ...
1
vote
2answers
243 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
2answers
82 views

ArcGIS 10.1 calculating area out of Aspects

I have used the aspect tool to visualize the 8(+ Flat) slopes of the different directions, now I would like to get the numbers of the areas for each different direction (+Flat). Anybody knows how that ...
1
vote
0answers
43 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 ...
0
votes
1answer
69 views

QGIS: graphical-modeler to calculate area of polygons

I'm trying to calculate the area of polygons using the field-calculator in QGIS (2.0.1). If I do this manualy it works fine, but if I do this using the graphical-modeler I get NULL as area for every ...
1
vote
1answer
60 views

How to analyse point data as covariate for areal data

I have two data sets: a) a set of polygons with areal data variables. b) point measures of various co-variates of interest (note I do not necessarily have a point for each polygon) How do I ...
0
votes
2answers
48 views

How to remove small areas without reducing borders

I'm having a problem where I am overlaying two maps to create a new kind of map with the data conjoined. In general this is good, but I need to remove the smaller areas from it. For the interior ...
0
votes
0answers
46 views

How to calculate the area of an ellipse on the earth's surface using Python?

I have a dataset consisting of GPS coordinates. I use a clustering algorithm to generate a two dimensional Gaussian for me. The Gaussian takes the shape of an ellipse if visualized on the map. ...
4
votes
0answers
27 views

Projecting polygon when calculating its area? [duplicate]

I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
2
votes
1answer
84 views

Compute the area of a given polygon (in vector format) lying between specified lines of latitude

I have species distributions (in vector format) and I would like to calculate how much of the area for a given species distribution is within certain lines of latitude, such as temperate and tropic ...
0
votes
0answers
25 views

Finding a common area by a set of ID variables?

I am trying to find a way to find a way to get matches of areas based on multiple sets of ID variables. I am using state-county and state-puma as an example below, but I am wishing to do this for more ...
1
vote
3answers
89 views

How do I calculate the new shapefile areas after clipping?

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 ...
0
votes
1answer
30 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 ...
5
votes
2answers
192 views

How to calculate the area between two line shapes?

I'm a newbie using QGIS (2.0). I'm trying to calculate the sidewalk area of a city. For that I have some shapes, extracted from Mricostation, with the topology (facades, fords, fences, etc.), but ...
0
votes
0answers
23 views

Show the paths but not roadsides and driveways in the line layer

I want to display paths in the woods but the paths are all in One (line) layer that contains all roadsides, pavements, drivvays, but also paths, tractor road and other relevant roads in, and up to the ...
1
vote
1answer
42 views

Equal (ish) areas Map Projection at the Tropics

What map projection (non-interrupted) preserves areas well for the entire tropical region? I am thinking of using a Cylindrical Equal Area or a sphere based version of a Cylindrical Equal Area or ...
2
votes
3answers
70 views

Relative areas projection independent?

I need to calculate how much (in percent) each of thousands of spatial polygons shrink after some events. I use R and the very useful sp-library. Example: Projection: "+proj=longlat +datum=WGS84 ...
0
votes
0answers
84 views

changing unit of area from unknown unit to square meters

I am using Qgis 1.8 and I have this polygon.Now I wanted to know the area of this polygon and i have used field calculator and it shows my area as 651692439.under general tab crs is : EPSG:4326 - WGS ...
0
votes
2answers
72 views

Show only some buildings

How do I show only some buildings? I only need to show 3 cabins in the forrest, but not every house in the whole village around, and the city close by. Maybe some of the symbol buildings in the city ...
6
votes
3answers
238 views

How can I obtain the same area values provided by the Census for TIGER boundaries using PostGIS functions?

In PostGIS, how can I compute the area of Census Boundaries and obtain the same results as are provided by the Census? For example, most Census Boundaries include attributes for Land Area and Water ...
1
vote
1answer
54 views

Is there any way to add an area column to new shapefile created from raster with gdal's polygonize in the same step?

I've been going through a fairly lengthy process of polygonizing very intricate raster images, then creating a new layer with the extra area attribute, so that I can then remove the millions of tiny ...
2
votes
0answers
20 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. ...
0
votes
0answers
47 views

How to paint area below certain elevation, using no coding and Google Maps, Google Earth, Bing

How can I show the area below a certain elevation, using Google Maps, Google Earth, Bing Maps or similar end-user application, and no coding? Thanks in advance
0
votes
0answers
59 views

How do I optimize the speed and enable ArcGIS to create the Service Area around my locations?

The Problem: Every time I try to solve the service area around locations, ArcGIS crashes. It takes forever to load facilities and draw just a single polygon. How do I optimize the speed and enable ...
2
votes
3answers
377 views

Calculate Area proportional

I have two tables both of them having polygon geometry. Lets consider Table 1 has bigger polygons which overlap over the smaller polygons in table 2.Now I know how to find how many polygons from table ...
0
votes
1answer
86 views

Area of a Cross Section GRASS GIS 7

I have a task I would like to solve with GRASS GIS 7, if somehow possible. I want to create a cross section from a landslide - and would like to calculate the area of that cross section/profile. Any ...
2
votes
1answer
97 views

extend the size (area) of raster

My problem is that I would like to multiply two rasters using raster calculation tool. Both rasters have values 0 and 1, but the covered area of first raster is bigger (100 x 100 miles) then the area ...
1
vote
2answers
77 views

how create a specific sub-study area in ArcGIS 10.1 - difficulties with classification

My study area is quite large (sometimes spanning across a few grid squares) and when I am running a viewshed analysis or calculating slope or euclidean distance it calculates for the entire region. ...
3
votes
1answer
181 views

Can't compute area of shapefile in field calculator

This shapefile represents the counties of NM. I am trying to compute the area of each polygon (yes, I know there is an area field, but this is a simpler example of a problem I'm having which doesn't ...
2
votes
1answer
46 views

How to choose an area (of mxn metres) within a raster that have values above a certain range

I've got a raster of concentrations of iron on Mars and I want to be able to choose several areas of either m by n dimensions in metres, or just any area in m^2, that encapsulate regions that have ...
1
vote
1answer
61 views

How to restrict buffer extent within land area only?

I need to create buffer for a point feature, but the buffer area will be restricted within the land area only. For example consider the following: A buffer of say 500 km radius is to be generated ...
1
vote
1answer
73 views

Tabulate Area for large datasets

I have been struggling trying to use Tabulate Area in Arc 9.3 for a large raster dataset. I have one raster with 8 land uses and another vector layer with zones (which I converted to a raster with ...
3
votes
3answers
211 views

Determining the area of each polygon within a polygon boundary?

I have a series of maps representing a 1000m diameter around a point. These maps contain 40 different types of polygons that represent a land use (ex. Corn crop, Pasture). I want to select all ...
0
votes
1answer
45 views

Newbie help — What do I need to calculate the 3D area of a terrain?

I have a terrain right on the side of a hill in Mexico. Initially I thought I could get the area from Google Earth, but after a few tests I found out that the area Google Earth calculates is flat, ...
0
votes
0answers
78 views

Query area without “AREA” field

In ArcGis 10.2 I'd like to show only polygons over 1m2, using something like a query. Can I do this without adding an AREA field and calculating/populating it in my table ?
1
vote
2answers
85 views

how to identify qgsvectorlayer area?

I need to identify the area from Qgis qgsvectorlayer anyone have an idea how to do that in python ?
0
votes
2answers
85 views

Count the area of rasterdata in specific shapefile polygons (residential density in different districts)

I'd like to count the exact area of three different residential classes (low, medium, high) by district of a shapefile which contains 225 districts. like: district 1 has: XXX sqm low, XXX sqm medium, ...
4
votes
1answer
82 views

Area calculation of an object without coordinates

I have a photo of an object with a scale and I want to calculate its area. I guess I have to create a polygon of the area to be calculated to use the 'field calculator'. But how do I tell the program ...