Questions tagged [spatial-analysis]
A set of techniques for analyzing spatial data
89
questions
0
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0answers
15 views
Understanding star parameter for esda.G_local
I'm completing some hot-spot analysis currently and am wondering how to treat the star parameter in esda's G_Local function.
The star parameter as described in esda documentation determines
whether ...
0
votes
0answers
12 views
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
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1answer
32 views
Determining the difference between two shp files
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 ...
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0answers
27 views
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 ...
0
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1answer
22 views
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 ...
2
votes
1answer
48 views
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'...
0
votes
1answer
39 views
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, ...
0
votes
1answer
15 views
Working out the area of certain class types within a polygon
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 which have specific ...
9
votes
4answers
562 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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0answers
33 views
Cannot read property 'demographics' of undefined in ArcGIS API
I have create a custom HTML page for Find Existing Location analysis following this link https://developers.arcgis.com/javascript/3/jsapi/findexistinglocations-amd.html#event-job-submit
I am able to ...
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0answers
15 views
spatially extract global hdf5 to subregion
I need to download some SMAP L4 soil moisture data from https://nsidc.org/data/SPL4SMAU/versions/4 .
The interface allows for spatial filtering to select a subregion of the global domain either by ...
7
votes
1answer
176 views
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 ...
0
votes
1answer
413 views
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, ...
3
votes
0answers
24 views
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 ...
1
vote
1answer
1k views
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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0answers
36 views
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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0answers
56 views
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 ...
1
vote
1answer
100 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 ...
1
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0answers
51 views
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 ...
0
votes
1answer
327 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 ...
0
votes
1answer
94 views
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 ...
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0answers
112 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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0answers
555 views
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 ...
3
votes
2answers
541 views
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 ...
2
votes
0answers
94 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?
2
votes
2answers
562 views
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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vote
0answers
674 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 ...
2
votes
1answer
90 views
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'...
0
votes
3answers
82 views
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, ...
2
votes
1answer
270 views
Horizon line of a vector point from terrain raster - global mapper
Is there a possibility to calculate the horizon line of a point with global mapper, not the viewshed, but just a line (or polygon) joining all the furthermost points from A and are at the same time ...
1
vote
1answer
476 views
Analyze time series NDVI using bfast
I would like to study a trend of NDVI data for a specific time interval using bfast package.
For this final aim, I read about the necessity to convert my data frame into a time series object in R. ...
2
votes
0answers
37 views
ArcGIS Online spatial analysis
I am currently attempting to put together a web mapping application for a client through the AGOL web app builder. One of the layers in the application is a set of grid cells covering a large ...
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0answers
26 views
Dividing space into homogeneous connected areas [duplicate]
Is there an algorithm (or software) for splitting a map into K connected areas such that the within-area variance of some variable is minimised, and the between-area variance of that variable is ...
3
votes
1answer
103 views
Unexpected results with Raster Terrain Analysis Plugin
In QGIS 2.18.18 on Windows 10, I have downloaded the NASA file srtm_05_01.tif that is available at http://dwtkns.com/srtm. I use the Terrain Analysis Slope method on that file with the following ...
2
votes
0answers
46 views
Finding the optimal boundary polyline in QGIS
I am looking to find an optimal boundary line between two geographically separated sets of points (a vector layer with S and N points representing two genetic lineages within a species). I would like ...
8
votes
0answers
360 views
Computing the horizon profile given a DEM in Python [closed]
Can anybody orient me towards an open source Python script that computes the 360° horizon profile (azi + elevation of highest topography in eye sight) from a single point (x,y,z) on Earth (account for ...
5
votes
0answers
944 views
Emerging hotspot analysis (space-time patterns) in QGIS
I worked with crime data a while ago and was really impressed by the possibility in ArcGIS to detect significant hotspots and their development over time (Emerging hotspot analysis).
Does anybody ...
2
votes
1answer
217 views
Analyzing population within buffer using raster population grid
I have a set of points and a population grid that is a raster file (http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density-future-estimates/data-download). I am trying to solve how many ...
1
vote
2answers
218 views
Coordinate systems for countries around Caspian Sea?
I'm trying to do spatial analysis of the Caspian Sea area and am not sure which projection to use for the countries around it. The Caspian spans multiple UTM zones and the countries around is are from ...
2
votes
1answer
207 views
Cluster analysis for different plant species with elevation, aspect, slope rasters using ArcGIS Desktop?
I am using ArcGIS Desktop.
I have a point shapefile for 5 different plant species and rasters (elevation, slope, aspect, canopy height). I am trying to find clusters for each species in terms of ...
2
votes
1answer
300 views
Use only points within a polygon for heat map in ArcMap?
I'm trying to make a point density heat map where the calculation for each cell considers only points inside a containing polygon and ignores those falling outside it (mainly because the outside ...
1
vote
0answers
409 views
Extracting a time interval from NetCDF-data in ArcMap Desktop 10.4
In ArcMap 10.4 (advanced licence) I have added a netcdf-file with EU-temperature-over-time data (time being every day between 1995 to 2016).
I just need the year 2010 from this data, but I'm still ...
2
votes
1answer
152 views
How does Spatial Join work under the hood?
I have a sidewalk_inspection points table and a sidewalk lines table. I want to do a spatial join between the points and the lines so that I can assign the ID of the nearest sidewalk to the ...
23
votes
2answers
1k views
What is this GIS Principle Called?
I've forgotten the name of a particular GIS principle and need a refresher...
Scenario: Let's assume there is some polygon which represents some administrative area. Let's say it's a square, for the ...
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0answers
70 views
Spatial Analysis Grouping/Clustering Question
If this question is incorrectly titled, I apologize; I wasn't sure exactly how to best phrase it. I'm working with my city's housing department to develop zones for building inspectors. One of the ...
5
votes
1answer
763 views
Why is QGIS points in polygon so slow when select is fast?
I'm looking at QGIS 2.18.9 and using a polygon to select points from a large point layer (file based tab file).
I wondered why the process is so slow if you use plugins or analysis options? I ask ...
0
votes
2answers
692 views
shortest distance between road and lake with PostGIS
I have a country-wide dataset with lakes (polygons) and streets (lines). For each lake I want to know the shortest distance to the closest street. (I do not necessarily need the closest street itself ....
4
votes
2answers
3k views
Cropping area of interest from raster file using Python?
I have been trying to crop out certain area of interest from a raster type .tif image format.
I was successfully able to implement that in R, but since shiny doesn't provide much for free, i have to ...
4
votes
1answer
104 views
Averaging points within a boundary
What I am trying to do is average a set of points with a separate boundary.
Each of the larger circles is a fixed distance around a sample point (typically the area sampled) with each of the ...
2
votes
0answers
288 views
Efficient way to analyze multiple (large) rasters against a different raster using numpy
The situation I have run into involves four rasters. I will try to explain each one and what it is for to help you get a better idea of what I'm trying to achieve.
One of the rasters has been ...
