Questions tagged [analysis]

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

43 questions with no upvoted or accepted answers
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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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1k views

Performing Multicriteria Analysis Using Distance Along Road Network?

There is the possibility that I will be working on a project which will look at thousands of properties in a region and measure their accessibility to different services (schools, parks, hospitals, ...
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66 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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402 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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39 views

Working with intersecting polar grids

I'm having some trouble figuring out the best way handle some GIS data. I want to analyze pollution from specific sites at specific points. I have a list of sites I'm interested in all across the ...
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475 views

Performing Raster Algebra and Multicriteria Analysis using FME?

I'm trying to use FME to do some raster algebra for some Multi-Criteria Analysis. At the moment, I have three rasters, all with the same extents and resolution: Slope, Hydro, and Infrastructure Mask. ...
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703 views

How do I create a leader line for a label in my bar graph in ArcMap?

I am displaying a bar graph of various tornado watches and warnings along with the actual tornado touchdowns themselves. Since the tornado touchdowns are such a small number compared to the large ...
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1k views

Mean coordinates in QGIS

I am using QGIS v 1.7.4 for MAC and I am trying to calculate mean coordinates for a set of points using ftools. To calculate my result I am going to Vector -> Analysis tools -> mean ...
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10 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. ...
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24 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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33 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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539 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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59 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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25 views

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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88 views

Is it possible to combine buffer zone analysis with time series analysis in QGIS?

There is a multitemporal analyzer in QGIS where it is possible to do a buffer zone analysis combined with time series analysis, where there are two layers an input layer and a target layer and the ...
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104 views

How to do regression analysis in SAGA for topographic correction

Currently I am trying to do the topographic correction using C-Correction. I would like to know if there is a way to do the regression analysis between L (uncorrected reflectance of each band from ...
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641 views

How to delineate a zone of slope break

I have a DEM of a region and want to delineate about a half-mile region at the base of hills (e.g. an area where the slope changes from steep to shallow). I ran the slope analysis tool and it kinda ...
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45 views

Analysis of concentrations

I process images of trace gases concentrations distribution over the layer of atmosphere. I need to analyse values of concentrations, rather detect so-called "background" values and "extremal" ones ...
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203 views

Calculating spread of invasive species using ArcGIS for Desktop?

I have ArcGIS Desktop Advanced and so far have completed the following; Used Supervised classification on a satellite image to identify the invasive species with field verification. I have converted ...
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839 views

How to calculate the average point spacing for a layer of points in QGIS?

I have a set of points and want to calculate the average point spacing for further analysis. ArcMap has the 3D Analyst Point File Information for this but I'm searching for an alternative in QGIS. ...
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144 views

Get pixel values ascii 50 files

I'm working with photos from a camera. The camera is arranged to take NDVI values instead of RGB for each pixel. I have several folders with 50 pictures in each folder as '*.asc' files the pictures. ...
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123 views

How to produce a simple ZTV/ZVI in openWind?

I'm struggling to get to grips with openWind. I need to produce a ZTV showing a 5km radius around the chimney of a proposed industrial development. I'm not sure of the height of the stack yet but for ...
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488 views

network based interpolation methods, which one could I use?

I need to interpolate traffic data consisting in raw number of vehicles passing across certain points, where counters are. It is evident I haven't a uniform distribution of points and values about ...
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61 views

Analyse effect of groups on raster maps

I work with a mechanistic model that uses climate data to simulate some specific output for different time steps and spatial locations. Now I want to investigate the effect of different climate data ...
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407 views

Divide polygon evenly based on lines and intersection points

I have this purple polygon illustrated in the figure below. I would like to split the polygon so that each line segment (green) split the polygon evenly with the surrounding line segments. A line ...
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2k views

Error #010067 when running spline interpolation

I am attempting to run a spline interpolation on a point dataset of 585 features in ArcGIS 9.3, using the spatial analyst toolbar. The dataset holds only latitude, longitude and abundance attribute ...
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456 views

GIS Maximum area coverage problem

I want to find optimum antenna location for an area. Every antenna can cover an circular area. These areas diameter is 750meter. So how can i find minimum number of antennas and locations. NOTE: I use ...
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100 views

3D tool for a visual analysis

Given a 3D mesh I need to visualize and analyze properties and elements generated from the object such as: tensors coplanar/similar elements ( coplanar faces, aligned vertices, etc etc, 3D geometry ...
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139 views

How to relate Slope map and Curvature map so as to have in the end PERCENTAGE PROBABILITY MAP?

i am trying to deal with road detection this last month. So i am working with particle filtering that produces particles, that means possible targets(to my case cars)/points, with hidden information ...
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1answer
2k views

Extract values from raster by using polygons

I am working with multiple raster files that cover all of united states. The file format of the rasters - GeoTIFF. I have around 100 geotiffs that I need to process. Then I have another shapefile with ...
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33 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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19 views

My service area polygons are not right, look more like road buffers

I have included a screenshot of my settings and what one of the polygons looks like. I have this set to approximately 10, 20, and 30 mile service areas and this entire segment is only about five miles ...
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30 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 ...
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10 views

ArcGIS Online Business Analyst Shared Datasets Dynamic or Static?

I am testing out a trial period of the ArcGIS Online Business Analyst extension and I have successfully created a business list points data layer that I have now shared in my ArcGIS Online ...
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43 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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16 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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16 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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17 views

Average raster value between points

I have a rasterized stream network, with point (species presence) data overlaying it. What would be the basic workflow for determining the average cell value between all possible combinations of ...
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41 views

Spatiotemporal analysis with polygons and points

In QGIS, I have a dataset of burned areas (polygons) and lightning strikes (points). In both datasets, I have the date of the fires, date of the lightning strikes, latitudes, and longitudes. However, ...
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21 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 ...
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1answer
67 views

Analysing landuse data in a buffer layer

In my project I want to analyse the landuse around some points within a certain radius. So I created a buffer around my points but I have no idea how QGIS could probably tell me what different ...
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56 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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241 views

GRASS 7.3 r.fill.dir Does Not Create Output Raster

I am running GRASS 7.3 on Mac OS X El Capitan (2.9GHz, 8GB RAM). I have had to disable SIP in order to run it, but it works. I am hoping to perform some hydrological analyses on a few DEMs. My DEMs ...