A density map depicts a number of objects per unit area.

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How to calculate the density of settlement per 100 square kilometers?

I have a point shapefile representing settlements. I want to calculate the density of settlement per 100 square kilometers. Should I use point or kernel density? I am working with ArcGIS. Is there any ...
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2answers
5k views

How to create a heat map or density map from stacked polygons in ArcMap 10

I have a polygon shape file that has many overlapping features. Each feature represents an area used by polar bears. So some of the polygons overlap and some don't, and there are separate clusters of ...
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2answers
205 views

Summing up over area based on distance related function?

Through a field study, we learned that the density of a bird species in the forest was related to the distance to forest edge: ln(density) = 1.89*(distance to edge) + 0.34 Now, for any forest ...
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1answer
406 views

Finding nodes with QGIS

As part of work in statistical mapping for school, I need to use QGIS to find the spatial extent of commercial nodes. A node is defined for this exercise as a zone of 75m in diameter where the ...
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1answer
2k views

How to Calculate Utilization Distribution Overlap Index (UDOI) in ArcGIS Desktop?

I was wondering if any of you happen to have any information on how to calculate the Utilization Distribution Overlap Index (UDOI) in ArcGIS 10? If I understand it correctly the UDOI takes two kernel ...
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2answers
705 views

Determine density or cover from a raster layer that has been clipped by a polygon

I am a very new GIS user using ArcMap 10. I have a raster layer of tree canopy that I have clipped so that the layer is in a polygon that is a circle with a 2km radius. I have done this for four ...
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1answer
2k views

How to produce density map in square kilometers?

I have a shp file with the location (lat, lon) of lightning spatial distribution. I want to produce a density map of lightning occurrence per square KM. I used density point function and I don't know ...
6
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613 views

How to redistribute population data using Python in ArcGIS?

I am trying to redistribute population data from census centroids among to housing density.Would you please help me to do that? I do have census area centroids (points) and the boundaries belong to ...
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678 views

Spatial join to kernel density / kernel density with polygon/point output in Arc [duplicate]

I'm looking for a way to join polygons to a density function for some other feature of interest. Current workflow make density raster from feature set of interest, using point/line/kernel density ...
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6answers
2k views

How do I make a heat or Choropleth map that uses polygons in QGis?

I've been playing around with the heatmap plugin for QGIS and I am wondering if it is possible to make heatmap with using a similar plugin/tool that uses polygons as well as points? I would like to ...
3
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1answer
110 views

V.kernel not working correctly in grass-6.4.2

I am using grass-6.4.2 for generation of heat maps of crime data. For testing purpose, I created a vector layer from my places shapefile which is a point data.The places shapefile contains more than ...
6
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2answers
352 views

How do I compute v.kernel maps in less than 16 hours?

I am using the GRASS GIS 6.4.2 bundled with QGIS 1.8.0, using a PostGIS dataset exported via v.in.org.qgis from QGIS, to create kernel density maps. The layer has 738,288 points. My problem is the ...
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3k views

Is population density considered continuous data and why?

Population counts are typically referred to as discrete or quantitative data. Why is population density a continuous data type when it is typically measured for aggregate areas such as census tracts ...
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6answers
6k views

What's the best way to produce a density map from weighted points in QGIS?

I'd really like to repeat the functionality of the ArcGIS Kernel Density tool - how could I do that? I would like to limit answers to easy-to-install free-and-open-source software – i.e. QGIS ...
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5answers
2k views

How to identify “true arcs” in Arcmap?

This is really annoying: the only good way of creating circles in ArcMap is using true arc, (compound curves) but I need to convert those to vertex (densifying) because of a compatibility problem. I ...
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0answers
367 views

kernel density with Grass-Qgis

Hello I am studying the use of GRASS GIS within Qgis and I need a little help with the understanding of the v.kernel module. I didn't find any human help within the manual (very cryptic) This are my ...
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2answers
1k views

How to densify a polyline according to a specific length? [duplicate]

Possible Duplicate: Add vertices to lines I am using QGIS 1.8.0 I would like to densify a polyline according to a particular length of segment (ex. 200 m). I know it is possible with other ...
5
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1answer
336 views

Adding kernel density output to map with ArcPy

I am trying to emulate the behavior of the Kernel Density tool from the ArcMap 10 GUI in a script; in other words, I want to calculate the density of a dataset, and add the visual result to a map. If ...
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1answer
1k views

What type of kernel density function does ArcMap use?

I know that there are several types of kernel density functions, such as uniform, cosine, Gaussian, etc. I was just wondering which one the "Kernel Density" functionality in ArcMap 10's Spatial ...
5
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1answer
3k views

How to do Kernel density analysis in QGIS 1.7?

Do someone have some suggestion? We would like to tray Kernel Density analysis as we did with ArcGis using QGIS?
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1answer
3k views

calculate building density in ArcMap

I have two questions related to calculate building density. I need to calculate the building density in a map which Data is in shape format. The buildings and the area are in two different layers. ...
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1answer
487 views

Finding intersection density for weighted lines connecting points across the continental USA

I'm working on an one-time problem that I'm hoping to solve with a computer program using free GIS libraries (preferably for VB.Net, C#, or Python... Java or C/C++ could work too). Alternatively, I ...
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1answer
1k views

How to calculate Line Density in QGIS?

I have a map of fracture distributions over an area and I would like to calculate the density distribution of fractures that intersect a moving window with a specified radius. Is there a way to ...
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1answer
191 views

Finding distance within which set percentage of features fall using ArcGIS Desktop?

Is there a tool that tells how many features there are within a set distance in ArcView? asked about finding the number of features within a certain distance of another feature in ArcView. I have ...
5
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3answers
2k views

What is the highest resolution of population density data that I can obtain for USA freely?

Ok so as far as my understanding goes the most high resolution dataset available that factors in many other things (other than Census data ) at a 1X1 km resolution is Landscan data created by Oak ...
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4k views

Dot Density Maps in QGIS?

Is there a 'friendly' way to create dot-density maps, where a polygon attribute data defines the number of dots (e.g. 1 dot = 100 ) using QGIS 1.7+? I say friendly because after a couple of hours ...
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2answers
8k views

Interpretation of ArcGIS Kernel Density legend parameters

In ArcMap 9.3 I've used Kernel Density to map various incidents, but the resulting shapefile doesn't display any units of measurement. Is there a good, not-to-technical source that would explain in ...
6
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1answer
529 views

Normalizing and adding kernel density rasters

I have 4 years of road kill data for one road, though each year has a different sample time frame (i.e. May-June vs. April-October) and therefore each year has a different number of surveys and totals ...
8
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2answers
3k views

Spatial statistics tools : clustering analysis on raster data

I've an apparently simple problem, but i can't find a clear methodology to use. I'm tasked to delimit "urban areas" by vector convex polygons, using the Gridded Population of the World dataset from ...
3
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1answer
626 views

Interpolating values within certain distance of points using ArcGIS Spatial Analyst?

Let's say I have a set of points representing bridges. I want to create a kind of "heat" map that would highlight areas within my study area that has many bridges in good or bad condition. I have a ...
12
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1answer
2k views

How do you use GRASS's v.kernel?

I am flummoxed on how to use GRASS's v.kernel. I have a vector layer of around 2.5 million points. I want to make a heat map using v.kernel to show concentrations, since I have variable instances ...
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3answers
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How to interpret GRASS v.kernel results?

GRASS manual reads: v.kernel - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel ... Ok, but how do I interpret the results? I understand that ...