Questions tagged [distribution]

The frequency or amount at which a thing or things occur within a given area or the set of probabilities that a variable will have a particular value.

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16 views

Generating a distribution map without x and y from given raster-grid into given polygons

I am working on an archaeological map for an excavation. I have given polygons which represent my archaeological layers (SE). Over that I have an grid with 1mx1m from which I have my findings. Each of ...
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31 views

How to create point attribute distribution map in QGIS?

I'm working with multiple species distribution data and am looking at creating what amount to density distribution maps of those species. I have a small number of site locations (18) and only 10 ...
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39 views

Bay Area Synthetic Network node/line coordinates

I just started working with the Bay Area Synthetic Network and was wondering if this dataset has location (lat/lon) information. I have visualized the files with QGIS, but when it comes to exporting ...
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11 views

Weighted random allocation of points

I'm trying to randomly allocate (a specific number of) points to raster cells which have different weights as value stored. Meaning: A point should be more likely to appear/get allocated to raster ...
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19 views

How to output a raster of special case's distribution with regard to overall distribution?

For example, the crime scenes are unevenly distributed in a city. Each case's scene can be represented as a point. Thus, we can generate a raster map, which shows the crime scenes' density in this ...
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39 views

Calculating number of rows for seperate objects (shapefiles) at once in QGIS

I have around 750 seperate shapefiles of species distribution data. For each species i want to calculate the number of atlas squares it occures in. Doing this for each object seperately seems a ...
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31 views

Electrical Distribution - ArcGIS

I am currently developing a project for which I need to make the preliminary design of the electricity distribution network topology for a population. For this I have the location of the consumers (...
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42 views

Color grid if values in grid exceed threshold - species distribution in QGIS

I have distribution data of a set of species (plants, mosses and lichens: 13 species total) in the Netherlands. I made a grid that divides the Netherlands into 1x1 km squares. I am not interested in ...
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236 views

Choosing kernel density radius [closed]

I have 3 datasets with GPS points. Two of those are GPS points that represent boating activities (two different types) and the third represents turtle observations. I would like to perform Kernel ...
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1answer
474 views

Plotting density map of points?

I have some points and I would like to plot the density map of them. I have tried like this: plt.figure() xedges = np.linspace(540000, 550000, 20) yedges = np.linspace(5200000, 5500000, 20) H, ...
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58 views

Spatial distribution of vector polygons

I have two vector layers and I am looking for a tool for spatial distribution of the polygons. polygon 1 is the frame, polygon 2 are objects with different size and distribution. I need an index value ...
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39 views

Generating random raster using weights with negative binomial distribution using R?

I'm trying to generate "species counts" in raster form -- essentially, the number of individuals in a species in a raster cell. I'd like to use the negative binomial distribution to do so. Normally I ...
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32 views

Distributing object distance using ArcGIS Pro?

Is there any tool in ArcGIS Pro, which could help me arrange objects to my desired distance? As an example, to see you what I am trying to achieve. ( in example objects are in chaotic distances)
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115 views

Underlying distribution of points in an ellipse

I'm attempting to generate both a uniform distribution and a normal distribution of points that fall within an ellipse shape, made from a centre point, semi major and minor and rotation in degrees. I ...
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1answer
29 views

How to create multi-scale variables from landcover data

I have calculated raster files with values of 0 and 1 for each landcover attribute I am interested in. I would like to make multiple raster files containing different cell sizes. e.g 100m2, 500m2, ...
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55 views

Loading points and polylines into PostGIS database and creating connectivity between them using topology?

I am new in PostGIS, and I am trying to create connectivity(using topology) between 3 sets of points and polyline to model an electrical distribution network. Does anyone know how to do this?
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74 views

Evenly assigning attributes to layer of points using ArcGIS Desktop?

I have a layer of point features at fixed locations. One of the fields in my attribute table has two possible values (lets say they are "a" and "b"). How can I modify this attribute as needed in order ...
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1answer
419 views

Using QGIS, automatically create n polygons fully covering an area without overlap with an approximately equal number of points in each polygon [closed]

I'm trying to avoid/simplify the following manual process intended to create a polygons layer with exactly n polygons so that each polygon encloses the same or close to the same number of points in an ...
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1answer
133 views

How to classify vegetation in 500x500 m polygons in a very coarse way in QGIS

For a simple species distribution map for the Dutch Wadden island of Terschelling, I want to give each 500x500 m polygon (reference grid = EPSG 28992) a specific color that coarsly corresponds with ...
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1answer
232 views

From areas of several species ranges (polygons) to a map (raster) expressing the count of overlapping polygons

I am not able to resolve the problem that follows. I have some separate shapefiles files, each one representing a given species range. Some layers have multiple polygons. I would prefer to solve this ...
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3answers
360 views

Representing Electric Switch in QGIS?

I'm working on building a GIS for Electric power distribution system. Can someone help me on representing an electric switch( With On/OFF state which will connect /disconnect downstream lines from the ...
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3answers
1k views

Creating n randomly distributed points within given (multi)polygon with PyQGIS?

Is there a way to create n randomly distributed point features within a given polygon using QGIS, PyQGIS and/or PostGIS? My first approach was to implement something like (fantasy language) n = 0 ...
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2answers
159 views

Species ranges into fishnet grids

I need to create a fishnet grid (presence and absences) form species distribution areas (polygon shapes). But I need to define that presence (value 1) is correct when more than 30% of the grid is ...
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1answer
245 views

QGIS: display spatial distribution data

For my Ph.D. thesis I'm looking at royal inscriptions from Mesopotamia (ancient Iraq), and part of what I'm trying to do is analyze their spatial distribution - i.e. how many were found at which ...
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95 views

Uniformly distribute spatial points over a given extent R

Within a shapefile I am given an integer attribute that indicates the number of points that will need to be evenly (uniformly) distributed over the associated polygons extent. These spatial points ...
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1answer
199 views

Create randomized raster with frequency distribution of second raster

I want to calculate resistance distance based on circuit theory for a set of species for the city of Berlin, GER. For the city area I use land cover, sealed soil and building height data. This data is ...
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69 views

Compare distributions of point patterns for significant differences in clustering

My problem is I have tens of thousands of points (GPS) representing animal locations over a period of several months. I want to test if a portion of those points (only about a few hundred) which ...
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1answer
442 views

Generate sample (Gaussian distribution) and store simulations in raster stack in R

I have a raster stack, one of the raster layers is the mean prediction of a property for that pixel, the second layer is the variance of the prediction. I would like to write a function for ...
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1answer
53 views

Constructing distribution graphs of attribute tables using ArcGIS field calculator?

Since I'm new to python I have an issue with writing the correct code to achieve the following. The picture is an example of an attribute table of which i want to make frequency distribution graphs ...
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2answers
85 views

Creating contiguous dispersal surface between two climate-change scenarios in ArcGIS for Desktop?

I'm modelling the distributions of Australian parrots in response to climate change. I have two climate scenarios (present and future), and have used Maximum Entropy modelling to generate maps of ...
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1answer
174 views

Nearest Neighbor distance frequency distribution

I have a dataset of 6455 points. Is there a way to produce the frequency distribution of nearest neighbour distances in the data set in ArcGIS 10.3? The Average Nearest Neighbor tool only produces the ...
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1answer
579 views

Is there a way to create a presence/absence matrix of polygons per cell in a grid using qGIS?

I'm working in QGIS with species distribution polygons and I want to know how many cells in a grid does the polygon overlap. I've tried creating random points within the polygon and then used vector&...
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107 views

Maxent Probabilities Values

I am working on my first experiment with Maxent. I am using two different species. When I receive the output map and look at it in QGIS the values for suitable habitat probability do not sum to 1. ...
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227 views

Risk and vulnerability analysis for the spread of alien species [closed]

Based on knowledge about the potential for proliferation of alien forests species we are looking at possibilities for modelling the process. Inputs should be area for initial plants, wind, elevation, ...
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1answer
205 views

Is there a way to create an urban extent/population distribution map which only includes areas with a population above 100,000

I'm looking to do analysis on cities throughout the world. I'm using WorldPop, LandScan and MODIS data to gain urban extent and population density maps. I would like to extract areas which have a ...
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2answers
90 views

How to create a realistic distribution of cities?

I'm not sure if this is the right community to ask this, so let me know if it's not. I'm wondering if there's been some empirical research as to how villages and cities are distributed around other ...
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95 views

Redistribution of polygons: supplementing and filling the specific area with polygons with specific size

I'm studying the impact of green wedges (red outline on the figure) on weather parameters in Copenhagen area. What I want to do is check how spatial redistribution of future afforested areas enacted ...
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4k views

Creating species distribution map?

I have to create some species distribution maps, but I have very little experience with ArcGIS unfortunately. I have two different kinds of excel sheets: 1. A version with many thousand X and Y ...
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1answer
164 views

is there an operation for measuring constancy (ecology)

I'm looking for an effective way to measure changes in spatial location in a time series data set (whether an observation repeats in the same location between successive time-steps, or if it shifts ...
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402 views

Distribution of POI query result

There are a lot of POIS in the database with fileds id name address lon lat. When we tried to query some points for a given bounding box, it is simple to build the accordingly sql and get the results,...
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91 views

Seeing whether set of postcodes have typical distribution to whole postcode population of UK?

For my dissertation I have a dataset of postcodes of 9984 that I am converting to coordinates atm. I looking to find whether this dataset has a 'typical or 'atypical' spatial distribution compared ...
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2k views

How to get an indication of how points are spatially distributed?

Let's say I have a set of points and I want to get an indication of their spatial distribution. That is, if all points are at one location a possible return value would be 0, whereas if all points are ...
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1answer
505 views

Comparing ranges and distributions of species, looking for correlation and differences between ranges

As a biology student just beginning with GIS, I wondere if someone could give me an idea of what tools to go about using to compare the range of 3 species that have trophic effects on one another. I ...
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1answer
283 views

Re-Distributing Python Toolbox

After reading this Esri article on how to distribute Python Toolboxes, I'm wondering how redistribution works? I have a few toolboxes that are in constant development, but would be useful to my co-...
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637 views

Empirical Bayesian kriging - does data need to be normal?

With empirical Bayesian kriging (ebk), does the data need to be normally distributed? If I apply a normal score transformation, my data is still not normal. Is ebk kriging thus an invalid ...
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76 views

Distribute population to health facilities (GP Practices)

I have been using GIS (ArcGis) for some years but I do not consider myself an expert. I am performing some analysis around GP Practices in London (UK), I would like to be able to estimate the ...
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2answers
91 views

Where to deposit global coverage dataset?

Some years ago I published a paper on Quarter Degree Grid Cells in the African Journal of Ecology. Quarter Degree Grid Cells (QDGC or QDS – Quarter degree Squares) is a way of dividing the longitude ...