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# 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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50 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, ...
45 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?
45 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 ...
30 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 ...
26 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)
62 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 ...
25 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, ...
230 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 ...
31 views

### Method to spatially analyse and compare sets of points with eachother

I have 3 sets of points represented by the image below (3 different shapefiles). Each point has a coordinate. All points represent the same type of real world feature (veterinary surgeries) Using ...
70 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 ...
283 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 ...
113 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 ...
209 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 ...
868 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 ...
144 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 ...
210 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 ...
90 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 ...
174 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 ...
67 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 ...
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 ...
81 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 ...
356 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 ...
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 ...
84 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 ...
162 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 ...
481 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&...
95 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. ...
222 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, ...
196 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 ...
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 ...
84 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 ...
592 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 ...
160 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 ...
340 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,...
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 ...
89 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 ...
483 views

### Simple way to compare ranges and distributions of species, looking for correlation and differences between ranges

As a biology student just beginning with GIS, wondered 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 ...