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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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Derive circle where circle contains half of the points in a dataset [closed]

I have a point dataset for my area of interest (AOI). A lot of the points are near the center of the AOI (it’s the downtown area of a major city). I have found the central mean. Then using that mean ...
Javier's user avatar
  • 11
0 votes
0 answers
30 views

NDVI temporal analysis error in Sentinel

I need to do a temporal analysis of NDVI with Sentinel images from 2019 to 2023, using monthly composites and extract the NDVI value for random points created. However, it is generating empty data. ...
Paula Duarte's user avatar
0 votes
0 answers
39 views

Create new LiDAR raster with levels above line height in QGIS

I have a LiDAR raster file and a line with river levels. I'm wondering if there is a way to do some analysis to essentially find bank tops in the LiDAR data that are below a certain level in the line ...
Gareth Lewis's user avatar
0 votes
0 answers
60 views

What is the hatch marking of my produced terrain slope raster?

I’ve been piecing together DEM raster data from different sources, in an attempt to create a terrain slope raster. I’m using ArcGIS Pro to merge the DEM’s together and then using the split raster tool ...
Whitney's user avatar
1 vote
1 answer
185 views

QGIS - Viewshed Analysis - could not broadcast input array

Whenever I try to make a viewshed analysis with only one point of interest, I get error messages. Is this because my Terrain model (GeoTIFF) is in ETRS UTM33 (EPSG: 28533)? I create a pointshape with ...
Marek's user avatar
  • 537
0 votes
0 answers
36 views

Give points attribute based on unique polygon

I have a problem that I can not solve. I've tried to find a solution in this forum, but with no sucess. I have one layer with points and one layer with polygons. The point layer have information ...
Rikard Lundberg's user avatar
3 votes
0 answers
264 views

Calculating specific building setbacks (front, side, rear) in QGIS

I am trying to analyze building setbacks for a large area (multiple suburbs). Setbacks needed: Front setback (minimum distance to street) Side setback (minimum distance to either side of the side ...
Keith's user avatar
  • 31
0 votes
1 answer
103 views

Centred Moving Average

I'm trying to retrieve the trend component from NDVI (MODIS) time series using the 4 centred moving average in excel, my problem is the time series has some holes in it (missing dates) I want to know ...
FF123456's user avatar
0 votes
1 answer
130 views

Can we do soil analysis for Nitrogen using remote sensing without field data for validation? [closed]

Background: Remote sensing is used for monitoring land cover change and for monitoring vegetation etc. In addition to that, it is used for soil analysis (alterations in soil properties) as well. There ...
th145's user avatar
  • 25
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0 answers
202 views

Route Analysis, Save Route Results with arcpy

I calculated routes with an arcpy script tool and now want to export or save it. If I try it with result_route.export(arcpy.nax.RouteOutputDataType.Routes, my_path) there is always an error. 'Result' ...
Saelon's user avatar
  • 65
2 votes
3 answers
911 views

Saga Tool "RECLASSIFY VALUES(SIMPLE)" missing in QGIS

I'm in a new field of research and I'm having troubles following a procedure with QGIS. I'm extremely new to all this since I'm a chemist. The aim is to calculate the total green cover from a photo. ...
dott. R. Zacco's user avatar
1 vote
0 answers
28 views

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 ...
Tessa Bell's user avatar
0 votes
0 answers
132 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)...
XaviBCN's user avatar
  • 21
2 votes
1 answer
2k 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 ...
Kirkman14's user avatar
  • 155
1 vote
1 answer
137 views

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 ...
AWGIS's user avatar
  • 3,230
3 votes
0 answers
316 views

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. ...
Chelsea_VictoriaS's user avatar
0 votes
0 answers
58 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 ...
Anonymous's user avatar
0 votes
0 answers
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 ...
Summer 's user avatar
7 votes
1 answer
3k 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 ...
cer.as's user avatar
  • 71
4 votes
1 answer
195 views

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 ...
Cookie's user avatar
  • 355
0 votes
1 answer
1k 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. ...
Ronja Kelch's user avatar
3 votes
1 answer
114 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....
Dean7's user avatar
  • 358
0 votes
0 answers
149 views

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 ...
Federico Franciamore's user avatar
4 votes
1 answer
1k 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 ...
Oisif's user avatar
  • 69
3 votes
0 answers
474 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 ...
Niklas Maier's user avatar
1 vote
1 answer
128 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 ...
Ben Rhoades's user avatar
0 votes
0 answers
140 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 ...
Anam Khalid's user avatar
0 votes
0 answers
55 views

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 ...
David Armstrong's user avatar
1 vote
0 answers
31 views

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. ...
Duncan Macdonald's user avatar
0 votes
0 answers
355 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 ...
Mathwiz's user avatar
  • 152
1 vote
0 answers
155 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 ...
Saba Jokhadze's user avatar
0 votes
0 answers
29 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 ...
Roland Wong's user avatar
4 votes
1 answer
598 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: ...
Konstantin Emelyanov's user avatar
0 votes
0 answers
88 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 ...
Pádraig Webb's user avatar
3 votes
1 answer
2k 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 ...
DGxA's user avatar
  • 119
1 vote
1 answer
71 views

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 ...
gis1234's user avatar
  • 319
0 votes
0 answers
29 views

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 ...
Tamas Kosa's user avatar
  • 1,509
3 votes
1 answer
223 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 ...
ecology's user avatar
  • 143
1 vote
0 answers
78 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 ...
Lisse's user avatar
  • 11
2 votes
1 answer
464 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 ...
csft306's user avatar
  • 649
0 votes
1 answer
143 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 ...
Manasvini Hariharan's user avatar
2 votes
0 answers
286 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-...
user avatar
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 ...
pyxis's user avatar
  • 41
2 votes
1 answer
2k 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 ~...
gis1234's user avatar
  • 319
1 vote
1 answer
893 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 ...
F. Lumley's user avatar
  • 167
1 vote
1 answer
1k 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 ...
Narelly Almeida's user avatar
2 votes
1 answer
749 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'...
F. Lumley's user avatar
  • 167
0 votes
0 answers
99 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 ...
Flavio Felix's user avatar
0 votes
1 answer
61 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?
Iftikhor Akhmadbekov's user avatar
6 votes
0 answers
233 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 ...
Mohamad Reza Salehi Sadaghiani's user avatar

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