Questions tagged [spatial-analysis]
A set of techniques for analyzing spatial data
110
questions
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2
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Cluster polygons into equal parts in QGIS
I have a large area divided into three parts. Each of these parts is divided into smaller parts. Each part contains an amount of biomass that can be cut and sold. The total amount of biomass in the ...
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0
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72
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Error using "if" in R: "== : missing value where TRUE/FALSE needed"
I am using st_covered_by function (from sf package) with a for loop and if statement to create a dummy variable to know if specific points from different municipalities are found inside the polygon of ...
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3
votes
1
answer
100
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Buffering with consideration of both distance and height using QGIS
I have a shapefile with points including their altitude (Z) and a DEM raster.
Basically, what I want is to create various buffers around the points extending up to 50 meters from them, but at the same ...
1
vote
0
answers
139
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Leafletjs split polygon
I have a polygon and it has circles on it. I drew lines from the intersections of the circles. Actually I want to split this big polygon by lines. I have numbered the polygons to be divided in the ...
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vote
1
answer
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Finding polygons that are only partially overlapped by another polygon [closed]
I've been trying to work through a problem using QGIS or ArcGIS (I have access to both). I have a Land Parcel layer (Polygon) and a Sewer Service Area layer (Polygon). Unfortunately, the Sewer Service ...
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votes
1
answer
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Extract non common areas between rasters in R
I'm trying to extract the non common areas between two rasters in R.
I have two rasters: yellow and red.
I want to extract all the points of the yellow that do not overlap with red (i.e. all the ...
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0
votes
0
answers
18
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Calculate new aggregated data using given aggregated data for different geographical unit
I have data aggregated (mean) on the neighbor level. And the same region is clustered using some criteria, and the relation is a new geographical unit. Are there approaches to calculating the ...
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How do I tell if a higher rate of (whatever) is due to higher population, or if its actually significant?
I hope that makes sense-- it's a bit difficult to word. We all know that more stuff happens in the places with more people, and less stuff happens in places with less people. What are some strategies ...
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1
answer
75
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Construct neighbors list based on condition
I am trying to build a neighbors list based on regions with contiguous boundaries, conditional on if a neighboring region has a policy implemented.
For example, say I have census tracts in New York ...
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1
vote
1
answer
352
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Creating regular sampling grid, with specific distance between points using R
I wish to create a regular sampling grid within m spatial polygon. Similar question is answered as Creating regular soil sampling grids using QGIS but I wish to use R.
In terra package, I can create ...
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51
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How to find optimal store location considering road availability and road condition using ArcGIS Pro
Recently, I am struggling with how to find optimal store location considering road availability and road condition using ArcGIS Pro. I have tried the location-allocation function in ArcGIS Pro. But I ...
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Residual bubble plot of krige.cv function dataframe
I want to plot a bubble plot of residuals from the krige.cv function with the bubble function.
However I get an error:
Error in as(obj, "SpatialPointsDataFrame") :
no method or default for ...
- 117
1
vote
0
answers
95
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Receiver points appear as circle around building footprints in Openoise plugin for QGIS
I have been trying to get receiver points using Openoise plugin for QGIS 3.18 Zurich but they appear in a circle form around the actual building footprints.This is a Noise Modelling tool that helps to ...
2
votes
1
answer
382
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QGIS spatial analysis grid nearest neighbour ERROR 4 No such file or directory Process returned error code 1
Whenever I try to run some form of spatial analysis by raster>>analysis>>Grid (Nearest Neighbour) or Grid (Inverse Distance to a Power) I am hit with the errors and message logs below. I ...
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votes
2
answers
105
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Performing interpolation using QGIS
I measured chemical concentration for different types of soil, and I have a picture or map of the distribution of different soils for my studied area. I assume that the concentration will be similar ...
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1
vote
1
answer
118
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LiDAR file only has first point returns
I am working on a LiDAR ALS file (provided as vertical rectified and classified as ground and unclassfied) which only has single point returns, which is strange because up until now all the ALS files ...
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3
votes
1
answer
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Setting the study area boundaries in QGIS for nearest neighbor analysis?
I've made a cursory (i.e., two hour) search of the Stack Exchange and the Internet to find out how we can set the study area boundary for the nearest neighbor analysis command in QGIS 3.16. Sadly, I ...
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2
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162
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R Set Spatial Points in a Matrix around given Spatial Points
I am struggling with the task to set one point in each pixel (of a given raster) in a distance of 3km of my points.
I tried buffering in QGIS and R but cannot find a way to set exactly one point in ...
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1
vote
0
answers
64
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Spatial relation (correlation) between polylines
I'm evaluating the spatial relationship between two polylines (morpholineament and magnetic lineament). If this two polylines are spatially correlated or not.
Traditionally, this analysis is realized ...
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1
vote
1
answer
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Non-infrastructure distributed vector processing in R
Is there a non infrastructure R option similar to disk.frame for geospatial vector distributed processing? I have come across the geospark package but am not sure if it requires spark to be installed.
...
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5
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0
answers
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Attribute table values randomly disappear or are changed
I'm using 3.10.14 version of QGIS and something very strange started happening. I performed several attraction distance and attraction reach analyses (using the Place Syntax Tool) that I saved in the ...
- 161
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0
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Calculating anisotropic cumulative cost using two cost surfaces (uphill and downhill costs) and a DEM in QGIS
I have two cost surface rasters, one representing the costs of going uphill (or level) and the other representing costs downhill. Using these plus a DEM and a vector layer for the source point, is ...
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1
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453
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Understanding Union analysis output using single feature class with overlapping polygons in ArcGIS Pro
I have a single polygon Feature class with about 33,000 shapes. I'm looking for overlaps.
I want to be able to say "Shape x overlaps with Shape y and Shape z"
So the UNION analysis tool ...
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2
votes
1
answer
157
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Order matched geometries on line by distance in PostGIS
I want to be able to find Points near (with a given threshold) a given Line-Geometry and Polygons that it crosses.
I already have that part of the problem solved, but now I'd like to order the results....
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432
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Maintaining Clip Layer Attributes When Using Clip Tool in ArcGIS Desktop
I am looking to clip master map polygons to land owner boundaries. However, the normal clip tool does not allow me to identify which land owner the master map parcel belongs to once it has been ...
0
votes
1
answer
146
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Determining the difference between two shapefiles [closed]
I have two shapefiles which contain data on the assessment of the quality of data collection in different areas.
data set 1 can be considered the most up to date and as such the template on which I ...
2
votes
0
answers
82
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A QGIS tool to perform cost surface analysis (as in ArcMap Path Distance)? not a least cost path nor a network analysis? [duplicate]
Within QGIS I am trying to perform a surface analysis to show the part of the terrain that can be reached from one or more source points in let's say 1, 2 and 3 hours of walk on the ground. That is to ...
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0
votes
1
answer
239
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Kernel density estimation for frequency data on polygon level
I would like to make kernel density estimations for a variety of influencing factors on crime, but I do only have frequency data on polygon level, e.g. number of drug markets on county level.
For all ...
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2
votes
1
answer
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Assigning values of points inside buffer to origin of buffer using QGIS
I have created a map with several bike routes. At each bike ride we have collected meteorological data and now I want to analyze and compare the collected data. My problem is that the GPS tracker wasn'...
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votes
1
answer
136
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Pairing line segments that follow a similar path
I have a shapefile with a regional travel model comprised of straight line features (model.shp, blue in the image). These lines roughly match the actual paths of the roadways they represent (road.shp, ...
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1
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Working out area of certain class types within polygon using ArcGIS Pro
I am using ArcGIS Pro.
I am trying to use a DEM to determine land management units based on combinations of slope and aspect.
As per the task I have created three individual boolean 'Class' rasters ...
10
votes
4
answers
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views
Finding closest points on another polygon
I have three layers:
polygons (having a unique id)
stops (having the polygon id it is laying on) (point)
possibilities (having the polygon id it is laying on) (point)
I now want to find the closest ...
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votes
1
answer
352
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Spatial analysis of classified grid using QGIS
I'm calculation the positional accuracy of linear features using the buffer method and dividing the region using a rectangular grid.
Here follows the vectos to be compared.
The grid cells were ...
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votes
1
answer
1k
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Calculating ERA5 2018 monthly 2mt temperature anomalies in Google Earth Engine
I am trying to calculate in Google Earth Engine using ERA5 the monthly 2mt temperature anomalies from January to December 2018 compared to the long-term reference period of 1981-2010. In other words, ...
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answers
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Analyze length of loops on network
I am working on a hiking network. Basically it is a selection of roads/paths suitable for walking/hiking. Each junction of three or four selected tracks is numbered. Each track is a line that starts ...
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1
answer
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Splitting a polygon by multiple linestrings leaflet and turf.js
I am trying to implement an utility for land subdivision using leaflet and turf. I am not sure if these tools are the right ones for the task. I've got it right for most of the scenarios but sometimes ...
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0
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Extract Census Blocks using Block Centroid that falls within Buffer in R
After creating buffer zones, I want to select a subset of Census Block IDs whose Centroids fall within the buffer zones. I have successfully built the data for all the Blocks and the designated ...
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1
vote
0
answers
96
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Balancing multiple supply and demand locations in QGIS
I am looking for a way to balance supply and demand with respect to distance, between two vector layers in QGIS.
I have two vector layers 50x50m grid
Supply (The red negative values)
Demand (The ...
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1
vote
1
answer
155
views
Frequency analysis of linestring using QGIS
I have a data-set that consists of linestrings across different timestamps. I want to identify the segments that occur the most frequently.
I am using R to import the data from JSON files, create ...
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1
vote
0
answers
64
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Overlapping area from data using QGIS?
I have a database containinig lots of data for each province. I'd like to know if there's a way to obtain areas of concentration of the phenomenon from the automatic overlapping of these data.
I hope ...
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0
votes
1
answer
813
views
Buffer analysis of points, counting intersects of resulting polygons
I am using ArcGIS pro and this is the first time I've done something like this. I don't have a "proper" GIS background and have just been plotting point maps and choropleth maps.
I've been asked to ...
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1
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149
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What does first requirement for LISA statistic mean?
According to Anselin, a LISA statistic have to satisfy two requirements:
The LISA for each observation gives an indicator of the extent of significant spatial clustering of similar values around that ...
1
vote
0
answers
207
views
Supervised Neural Network for site selection in GIS [closed]
I have a set (A) of geospatial raster data layers and a set (B) of point data.
(B) includes numerical values that indicate the "suitability" of the specific site with a rising value. I know that (B) ...
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1
vote
0
answers
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Finding nearest distance between point and polygon layers in QGIS
I am using QGIS to undertake an analysis for a project.
This involves a polygon shapefile, which represents a boundary of a site, and a series of points which represents the location of parks.
I ...
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3
votes
2
answers
1k
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Find what polygons are not fully covered by union of polygons from another layer in PostGIS
I have two tables in a PostGIS database
>>> select postgis_version();
"2.5 USE_GEOS=1 USE_PROJ=1 USE_STATS=1"
One represents the country borders and another one is administrative ...
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2
votes
0
answers
145
views
Count the number of points of a multipoint-feature [duplicate]
I try to use the fieldcalculator in QGIS 2.18 to count the number of points of a multipoint-feature. Is it possible?
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2
votes
2
answers
1k
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Moving multiple points in batch using ArcGIS Desktop?
I have multiple parcel polygons and they all have one side touching the lake polygon. Each parcel polygon has a point inside which is now at the centroid of the parcel. I need to find a way to move ...
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1
vote
0
answers
805
views
Comparing speed of Spatial Analysis with GeoJSON versus shapefile in QGIS?
I have a large dataset that I want to perform spatial analysis on in QGIS.
Specifically, I want to perform a polygon intersection analysis between two polygon layers.
Given the size of the dataset ...
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2
votes
1
answer
176
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Finding remoteness of point using QGIS?
I'm sure this shouldn't be as tricky as I'm finding it but does anyone know how you can find the 'remoteness' of a point compared to multiple other points in QGIS?
I have a shapefile containing 1000'...
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votes
3
answers
98
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Seeking article on network analysis, connectivity analysis, and proximity related to routes and influence of stations? [closed]
Unfortunately, I lost a document I had found on the internet, and I do not remember the title. The article was like a guide or recipe and it was in PDF format, and it was related to network analysis, ...
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