Questions tagged [analysis]
The process of extracting geographic, statistical, geometric, or scientific information from one or more related collections of GIS features and data.
236
questions
0
votes
0
answers
33
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 ...
0
votes
0
answers
51
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 ...
- 1
1
vote
1
answer
108
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 ...
- 519
0
votes
0
answers
33
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 ...
3
votes
0
answers
183
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 ...
- 31
0
votes
1
answer
71
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 ...
- 41
0
votes
1
answer
81
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 ...
- 25
0
votes
0
answers
147
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' ...
- 65
2
votes
3
answers
551
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. ...
1
vote
0
answers
27
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 ...
- 67
0
votes
0
answers
121
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)...
- 21
2
votes
1
answer
1k
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 ...
- 155
1
vote
1
answer
128
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 ...
- 3,200
3
votes
0
answers
253
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. ...
0
votes
0
answers
54
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 ...
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 ...
- 1
6
votes
1
answer
2k
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 ...
- 61
4
votes
1
answer
173
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 ...
- 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. ...
3
votes
1
answer
100
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....
- 358
0
votes
0
answers
140
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 ...
4
votes
1
answer
924
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 ...
- 69
3
votes
0
answers
401
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 ...
- 31
1
vote
1
answer
113
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 ...
- 39
0
votes
0
answers
134
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 ...
- 29
0
votes
0
answers
54
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 ...
1
vote
0
answers
29
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. ...
0
votes
0
answers
316
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 ...
- 152
1
vote
0
answers
147
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 ...
0
votes
0
answers
27
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 ...
4
votes
1
answer
534
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:
...
0
votes
0
answers
73
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 ...
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 ...
- 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 ...
- 187
0
votes
0
answers
28
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 ...
- 1,475
3
votes
1
answer
206
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 ...
- 143
1
vote
0
answers
73
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 ...
- 11
2
votes
1
answer
418
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 ...
- 649
0
votes
1
answer
134
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 ...
2
votes
0
answers
253
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-...
user127468
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 ...
- 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 ~...
- 187
1
vote
1
answer
833
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 ...
- 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 ...
2
votes
1
answer
730
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'...
- 167
0
votes
0
answers
90
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 ...
- 93
0
votes
1
answer
54
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?
6
votes
0
answers
218
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 ...
1
vote
1
answer
2k
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, ...
- 485
1
vote
1
answer
348
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 ...
- 305