Questions tagged [analysis]

The process of extracting geographic, statistical, geometric, or scientific information from one or more related collections of GIS features and data.

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Multi criteria analysis or k-means clustering

I have more of a research question. If I have point locations (say gas stations) and information about the gas stations (area, type etc) and I want to determine which gas stations would potential be ...
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54 views

Visibility Analysis crashes QGIS 3.22

Every time I try to perform any of the tools from the Visibility Analysis plugin QGIS crashes. I'm using the latest LTR, QGIS 3.22.4. When I click any of the options (Viewshed, Visibility Network, etc)...
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2 votes
1 answer
133 views

Turf.js lineIntersect() not giving intersection of lineString and feature?

I'm displaying some polygons in Leaflet, and using Turf JS to do some calculating. After drawing a line between the centroids of two neighboring polygons, I want to find the intersection of the line ...
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1 answer
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Assessing locations across England with at least four retail shops from four different retailers in GIS

1A: Problem I have a dataset (point data) of 500 retail shops across England distributed in a seemingly un-random fashion (some retailers may only be found in cities or in specific regions). There are ...
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2 votes
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Rainfall trend analysis in Google Earth Engine

I have an image collection of images representing total seaonal rainfall from 1980-2020 in my study area. I want to run an analysis which identifies if a pixel has any significant trends i.e. ...
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44 views

Multi-year analysis of points at the same location

I want to do a multi-year analysis in QGIS. One of my clients would like a map indicating the overall mean for his Yield Data going over 10 years. I have my 10 years points separate. How do I combine ...
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25 views

Highlighting Specific Proportion of Data Layer using ArcGIS Pro

I am trying to highlight an arbitrary percentage of a coral reef vector layer. I am trying to see what 30% of this layer looks like, but I cannot figure out how to do this. I tried customizing the ...
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6 votes
1 answer
645 views

Raster data viewshed analysis with Python

I want to write an algorithm that performs viewshed analysis in Python programming language using digital elevation model. I generated points from pixels from the raster data in QGIS. I calculated the ...
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4 votes
1 answer
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Efficient analysis of large amount of CSV files in QGIS

I have hundreds of CSV files with geometry values in the same folder, and I'm trying to import all into QGIS, and use 'count point in grid' function to see how many of each data on each grid. I've ...
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  • 131
0 votes
1 answer
188 views

Linear regression analysis in R [closed]

I would like to conduct a simple linear regression analysis in R with two grids. So I have two Raster images of the same region and I need to do a regression analysis, but I struggle with doing that. ...
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3 votes
1 answer
38 views

Split population number by area

So, I have a polygon that contains the population number. Another polygon is a zone polygon. I need to approximate population from the first polygon to zones polygon, but based on intersection percent....
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  • 398
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Iterating over each pixel of an image in the time-series

I am using on GEE for a small analysis of Sentinel-1 data collection. I would like to go through each pixel of my AOI and check whether there was a drop in the time-series and classify that pixel ...
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3 votes
1 answer
562 views

Accessibility analysis using isochrones and network analysis tools QGIS 3.16

So I made an isochrone using ORS Tools plugin, as well as using the Network analysis toolbox to analyze the service area of the bus stop. Ultimately I want to provide a statement of X% Area covered ...
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1 vote
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How to define the spatial distance ε for EDR and LCSS similarity algorithms?

Let's assume a dataset with human trajectories like Geolife. I want to measure the similarity of two random trajectories from this dataset using the EDR or/and LCSS algorithm(s). I wonder, which ...
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3 votes
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149 views

Using Aspect tool in QGIS

For my bachelor thesis in biology I´m working with QGIS 3.14 (Pi) and tried to create a layer where the slope aspect/expositon/exposure is presented. I´ve got a DTM1 on hands. There is this function ...
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1 vote
1 answer
71 views

Creating radii around points, analyzing raster & vector data within those radii, QGIS 3.10

I have a handful (literally, like 20) points that I need to create three radii around— 200m, 1000m, 2000m— so that I can extract raster (land cover within the radii) and vector (road length within the ...
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59 views

Calculate Percentage population from Vector Grids

I have a vector grids layer of population (shapefile). Each grid represents population in that grid and have the following attributes: Area Population I want to calculate and display the percentages ...
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Analyzing NDVI rasters with same dimensions but different extents with Raster Calculator

I have drone sourced remote sensing imagery (NDVI) of a trial site set up to measure yield response to varying nitrogen (N) rates. The trial includes N rates ranging from 0 to 600 kg/ha. The trial ...
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1 vote
0 answers
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QGIS Centre Pivot Wheel Vector Height Intersection With Raster

I am trying to visually display a centre pivot irrigator against a DTM Raster file to check terrain clearances in QGIS. I have a 1m DTM Raster and polygon/and line vector files of the pivot wheels. ...
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0 votes
0 answers
172 views

Intersect_analysis in ArcPy "The table was not found."

Is there a bug in ArcPy? I have two features I want to intersect in a feature data set using ArcPy (this is a small part of a bigger program). Let me preface this by saying that when I do this in ...
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1 vote
0 answers
68 views

Creating Least Cost Path with cost distance analyse

I'm trying to create Least cost Path analyse between two points in QGIS. I had DEM and from this I created Slope with various elevation values. Then I made two points with different layers. Both of ...
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24 views

Service Area - Not taking into account of all network

I'm trying to work out an 800m service area from a station. However, QGIS is not taking into account some of the network lines. The yellow colour highlights the network that should be included in the ...
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4 votes
1 answer
343 views

Difference between ST_Simplify function in PostGIS 3.0.0 and PostGIS 2.5.3

Faced such a problem (or maybe it's a bug). I get different results when using the ST_Simplify function in PostGIS 3.0.0 and PostGIS 2.5.3. There are source data that are simplified by using a query: ...
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0 votes
0 answers
35 views

When carrying out spatial point pattern analysis on my point files I get an error for standard distance

How to fix an error with standard distance in spatial point pattern analysis. When performing spatial point pattern analysis QGIS 3.4 is only carrying out the mean point calculation correctly and ...
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2 votes
1 answer
1k views

Least Cost Path Analysis in QGIS?

For my Bachelor's thesis I try to reconstruct a road betweeen two ancient cities. One method I'd like to try is least cost path analysis with QGIS. I've worked with QGIS before, but mostly only ...
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1 vote
1 answer
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2 raster files, find suitable area [closed]

I have done this with vector before, but now I have 2 raster layers: 1 raster layer that refers to land use: urban, forest, water, agriculture 1 raster layer that was classified in 3 classes for ...
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  • 139
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0 answers
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Is there any method to generate the minimum number of intersecting grid squares to a polygon?

I know I can generate a group of fixed sized intersecting square grids for a polygon using the bounding box of the polygon and generate gird squares on that and keep those, which are intersecting with ...
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3 votes
1 answer
138 views

Assign points within 150 meter buffer of each other the same unique identifier?

I have a bunch of points on a QGIS map. Each point is a unique sampling event. However, some of these points have been sampled multiple times but there is no common identifier in the attribute data to ...
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1 vote
0 answers
48 views

Vector to grid - Computing statistics by grid cells

I have a vector point data from drifting buoys (speed, direction, sst, slp) that I want to analyse in a grid. What are the right tools for this? Example of my points data below. Each point has the ...
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2 votes
1 answer
247 views

Do Not Filter vs Ignore Invalid Geometries

In QGIS 3, What's the difference between "Do not filter (better performance)" and "Ignore invalid geometries"? Both can be found at Settings > Options > Processing > General Both are options to ...
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0 votes
1 answer
94 views

Viewshed Analysis for Custom DEM file [closed]

I am new to qgis and trying to do 2 things. My objective is to have an accurate viewshed analysis at the end. But my DEM file is of poor resolution. I do have a shapefile with building height ...
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2 votes
0 answers
105 views

How to automatically compare two aerial photographs with a GIS with regard to certain features?

At present, we are trying to automatically record the new use of land by buildings by systematically comparing aerial photographs (e.g. 2007 farmland -> 2008 warehouse). For this purpose, high-...
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1 vote
1 answer
31 views

Selecting Different points in 2 different layers

I'd like to make an analysis on points. I've 2 layers they have house numbers as an attribute. What i'd like to do is compare these 2 layers and select the different ones. Geometrically there are ...
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2 votes
1 answer
1k views

Network service area - QGIS

I want to check if schools from my hometown are accessible for students who use public transportation, so I need to perform this analysis in order to see if the schools are located in the range of ~...
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  • 139
1 vote
1 answer
714 views

Count points in polygon (weighted) for multiple attributes in QGIS 3 in one go

Is there a way to count weighted points inside polygons for multiple attributes at one time? I can count weight points (below) for an individual attribute, which creates a new polygon layer with an ...
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1 vote
1 answer
841 views

Stereoscopic Interpretation on QGIS [closed]

I would like to know if anyone has worked with stereoscopic analysis (e.g extracting features such as drainage, forest an so on) using the following softwares: QGis, gvSIG, ILWIS or MicroImages TN ...
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2 votes
1 answer
628 views

Count points in polygon (weighted) in QGIS 3

In QGIS 2 you could perform a weighted point within a polygon layer using Processing toolbox > Vector Analysis > Count points in polygon (weighted). I could well be missing something, but I can'...
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0 votes
0 answers
72 views

Network Analyst takes so long

Is there some kind of limitations of number of features when we work with Network Analyst in SDE ? My net has 170.000 features, is it a problem ? Because it take at least 6 hours to finish the "Build ...
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0 votes
1 answer
27 views

How to define the angle of points on slope?

I have point data set and DEM and my task is to identify how many points are falling on the slope of more than 40 degrees. How could I do this in ArcMap?
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6 votes
0 answers
153 views

Using the height of river to approximate its extreme flood boundaries - terrain analysis in QGIS?

Using QGIS I'm trying to analyse an area/DEM with this criteria: - heights 10 meter above the river-centerline in both sides of river. I can do it with the calculation of contours (2m) from DEM and ...
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1 vote
1 answer
1k views

Calculating population size from raster layer using QGIS?

Is it possible (using QGIS) to calculate the population size from a raster layer within a certain area? For example: I have a population density raster layer (100x100 grid cell) for South Africa, ...
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1 vote
1 answer
174 views

Make rasters to show the extent of certain data values

I'm trying make a raster of the area between 5 and 10 thousand feet in Colorado. I have DEMs, and I'd like to make a raster where all the area in this range is a value of 1, and the area outside the ...
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2 votes
2 answers
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Private Surface Water Mains In Between Public Mains Analysis

I am working in a geometric network of a surface water (stormwater) system. We have both public and private assets (pipes/mains, manholes, inlets/CB's, etc.) in the network. I am doing a bit of QC on ...
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1 vote
0 answers
965 views

Standard Method to calculate Average Moving Speed from Times & Coords?

...I wasn't sure if this question was best suited to GIS, SO or Math, so after reading GIS Topics I decided to ask here, but I'll relocate if necessary... :-) I'm working on automating various ...
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2 votes
0 answers
517 views

how to calculate cumulative cost of movement, accounting for wind direction, in R?

I am trying to reproduce the calculation of the duration of sail-powered navigation as described in an academic article (http://www.tandfonline.com/doi/full/10.1080/15230406.2017.1403376), but using R ...
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0 votes
1 answer
289 views

GWR with dependent and explanatory variables in different files

I have a point shapefile (let's say A) with pollution measures (let's say Y). My hypothesis is that pollution at theses locations is primarily driven by nearby industrial units and not by activities ...
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1 vote
0 answers
66 views

Road Network Accessibility

I am working in qgis with 3 layers: one is road network and other is hospitals and locations of accidents , later two layers are as points, I want to figure out what accident location (points ) are ...
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-1 votes
2 answers
2k views

Determining if polygon falls within another polygon using QGIS?

How can I determine if a certain polygon falls within another separate polygon using QGIS?
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  • 629
2 votes
1 answer
106 views

network analysis that includes user defined nodes

I want to make network analysis using python. I want that user must be able to select point of interests and calculated route must contain that points. For example between start and end nodes user, ...
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1 vote
0 answers
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Are tesselation patterns an effective way of covering a shape?

I am using Facebook place search to explore business pages on Facebook. If I input a longitude and latitude into facebook's GraphAPI, I can search within a given radius for facebook business pages. ...
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