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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19 views

Working on query builder in QGIS?

I installed QGIS 2.16.1 and i want to work with the data using query builder. It was active and when i click it nothing pops us and now it is just deactivate. Is it related to plugin or what ?
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0answers
19 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 ...
2
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0answers
19 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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1answer
26 views

Weighted polygon-feature-classes combination/overlay analysis using ArcGIS for Desktop?

I have several (sometimes, not always overlapping) Polygon Feature Classes which are all weighted/ranked through a field from 1 to 10 (10 is best). I would like to combine/overlay these layers them, ...
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1answer
21 views

Can I split my data based on the polygons in a different layer?

Carto has a built-in dataset with polygon data for UK administrative regions. I have put another layer over this, containing several thousand data points (postcodes). Is there an easy way to find out ...
2
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1answer
19 views

Calculating standing times

I have n objects and each object has m positions. Every position is defined by x, y (in millimeters) and a (unix) timestamp. { objId: 'a-b-c', x: 123, y: 567, date: 123456789, } Now I want ...
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0answers
25 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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1answer
23 views

How to group overlapping polygon features to generate unique feature ID?

I have a group on onshore leases that are overlapping and I want to generate a field attribute so that all the polygons (or centroids of the polygons) that overlap have a unique ID so that I can ...
3
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2answers
53 views

How to calculate shortest distance from start to end of river?

How can I calculate the straight distance from the start to the end point of a river (red line in image)? I don't know how to do this automatically.
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1answer
22 views

Add a random value of the order of 10^-2 to raster layer?

I was doing some raster analysis for smoothing in ArcGIS, one of my task is adding a random value of the order of 10^-2 to a raster layer. Does anybody know how to do it?
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2answers
246 views

Do any Basketball Coaches use GIS?

The LA Times has a leaflet map viewer app showing all 30,699 shots in Kobe Bryant's career. It seems like spatial analysis could be useful for certain coaching decisions. Are any coaches actually ...
2
votes
1answer
38 views

Cell-by-cell analysis of values of buildings in a city

I'm absolute new in GIS. My task is to estimate the wind energy potential in a part of a certain european city by using a given method which is based on the calculated roughness of cells of one ...
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2answers
83 views

QGIS NDVI Spatial Analysis

I have an NDVI raster that I would like to reclassify into some arbitrary bins i.e. all values between 0 - 0.2, 0.2 - 0.4 etc. for spatial analysis. Could anyone advise how to: 1) reclassify a ...
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1answer
55 views

Nearest Neighbour analysis between points in 2 tables utilizing with distances set along specific polyline roads

I'm trying to do a Nearest Neighbor analysis between points in 2 tables utilizing with distances set along specific polyline road files I have. I am attempting to determine the most cost effective way ...
0
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1answer
21 views

Is there any water quality toollbox which can be used in water quality analysis [closed]

I just start my job in water quality analysis,I wonder that do we have any toolbox to do water quality analysis in GIS
4
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1answer
53 views

The source of and possible solutions for DEM anomalies?

I am working with a DSM (Digital Surface Model) created using stereo-paired spot 6/7 satellite imagery. This DSM, and metrics derived from it will be used to create a Predictive Ecosystem Map (PEM). ...
3
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1answer
43 views

Distance matrix tool, how to include distances at 0 metres?

I have used the Vector -> Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, the points that match exactly, or that has 0 metres between them ...
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1answer
33 views

QGIS: Distance Matrix tool omitting some points in output table. (qGIS 2.10.1-Pisa)

I have used the Analysis Tools -> Distance matrix to merge two datasets by the closest points. But in my output csv file, some of my points are left out. In the original datasets, none of these points ...
3
votes
1answer
115 views

Counting polygons in one layer that are overlapping/touching/contained in each polygon in separate layer of contiguous polygons using QGIS?

I have a layer of contiguous (pink) polygons (UK Parliamentary constitutencies) and a separate layer containing (blue) polygons representing protected nature areas (Natura 2000 areas): Each ...
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0answers
50 views

Modeling Gun Safety

I am attempting to wrap my head around a modeling workflow for gun safety. I have been tasked with developing a model that would identify locations where discharging a firearm would result in the ...
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0answers
37 views

Analysing TMS / WMS usage and performance

to tune my webservices, I like to know, if there are existing anlysis tools to measure spatial requests (similar like Piwik does for web requests). There is Maptiks as service, but I'm looking for an ...
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0answers
50 views

Missing data in exercise in training manual? (Qgis training manual 2.6)

I'm following the Qgis training manual 2.6. The step 7.4.1.2 (according to http://docs.qgis.org/2.8/en/docs/training_manual/vector_analysis/spatial_statistics.html )doesn't generate a new SHP with ...
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1answer
110 views

Slope analysis of DEM in QGIS?

I have very strange problem with the raster analysis. I have a DEM as a Geo tiff and I do a slope analysis in QGIS. I've done this many times and everything was ok but this time I received reversed ...
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2answers
62 views

How to set independent path in QgsOverlayAnalyzer >> intersection statement using Python?

How to set independent path in QgsOverlayAnalyzer >> intersection statement using Python? QgsOverlayAnalyzer.intersection(QgsVectorLayer, QgsVectorLayer, QString, bool onlySelectedFeatures=False, ...
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1answer
35 views

Does ArcGIS Online include High Speed Rail in its network analysis?

I'd like to run an OD Matrix using network analyst in Europe and Asia to study high speed rail. Does ArcGIS online include HSR (such as the AVE in Spain or the TGV in France) in its analysis?
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1answer
191 views

Arcpy Intersect analysis function returns an error when using certain types of strings for input

In an arcpy for the intersect_analysis function, certain syntax works and others don't. What is the reason for this? Works: arcpy.Intersect_analysis("'D:\\Program Files (x86)\\ArcGIS\\data\\uscities....
3
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2answers
140 views

Which SRIDs to use for what tasks?

I try to understand the idea behind the different Spatial Reference Identifiers. I understand that the different SRIDs identify different projection views on the earth and that they are important for ...
5
votes
1answer
196 views

Dividing polyline layer in clusters with specific requirements in ArcGIS for Desktop?

For my work in ArcGIS 10.2 for Desktop I need to divide line layers into clusters/groups. Currently I am doing this manually, but I like to automate this. The line layers can consist of 50 up to 2500 ...
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votes
1answer
66 views

How to determine how many times an area was burnt? [duplicate]

In arcgis I want to find from various forests fires shp files how many times parts of a particular forest were burnt during the last 70 years. Is there a way to count overlapping polygons?
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2answers
36 views

Visually identifying areas where older poles predominate?

I have a dataset of 300,000 poles including a number of attributes including pole age. What I'd like to do, ideally, is be able to distinguish areas that have more old poles. Unfortunately I can't ...
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0answers
70 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 ...
1
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1answer
64 views

Identify nodes in GRASS

Apologies if this is a really basic question but I have been unable to sort this out: How do I identify nodes in GRASS? Specifically, I am running a Salesman analysis and get the following error ...
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1answer
272 views

How to read GeoCSV with OGR?

I have a GeoCSV file which stores the geometry in a WKT formatted cell following this recommendation: "identifier","date","geom","value" "Dgf01","15.04.2013","POINT (52.404869 13.147457)","285" "...
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0answers
44 views

Aggregate polygons based upon adjacency to an acreage threshold

I work as a forester. I have a feature class of approximately 750 polygons that range in size from a few acres to more than 250 acres. I would like to combine these polygons based upon their proximity ...
9
votes
1answer
363 views

PostGIS polygon edge analysis (orientation, edge length)

I am rather new to the world of GIS and especially PostGIS, so please excuse me if the answer seems evident... I would like to do analysis on a number of buildings. One thing I am interested in is ...
1
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2answers
747 views

How to calculate Cost Surface Analysis in ArcGIS 10.x

I have about 10 points and I want to run Cost Surface Analysis. I’m trying to find what distance a person can walk in a given amount of time from a certain point (5-10 or 15 minutes). What procedure ...
0
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1answer
458 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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0answers
247 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. ...
5
votes
2answers
388 views

Calculating edge length of polygon within overlapping polygon

I have a layer of wetland polygons and a layer of lakes. I basically want to find the total length of lake shoreline contained within each wetland and add these values as an attribute of the wetlands. ...
0
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1answer
172 views

error in selecting data from attrribute table QGIS

First of all, im not sure why all the data points from my csv file does not show up on qgis. I enabled custom delimiters to commas and still have no clue. it worked for my other vector layers except ...
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1answer
85 views

non alignment of base layer and other vector layers

i'm sure you've encountered this problem repeatedly. i've tried all different methods. Enable on the fly crs transformation. go to settings and options to use crs data. go to properties and change ...
1
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1answer
176 views

Analyzing long lat location data to find locations in proximity

I am looking for a tool to analyze location data (long lat values from vehicle GPS available). The goal is to identify locations which are in close proximity (within a circle of 30-60ft) and then ...
4
votes
1answer
194 views

Measuring Sinuosity of Walking Paths

I'm currently working on a project that examines the movement of consumers through different kinds of retail spaces in Central Asia – namely, bazaars versus supermarkets. I've equipped dozens of ...
3
votes
1answer
2k views

Calculate and add area of overlapping features within polygons

I have a polygon layer of watershed boundaries And a single multipart feature that contains all public lands for the state. I need to find the area of public lands within each watershed and add it ...
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vote
1answer
54 views

How to add analysis privileges to ArcGIS Online application?

I'd like to use ArcGIS Online analysis services in my web app application. When I try accessing the service: http://analysis.arcgis.com/arcgis/rest/services/tasks/GPServer?f=pjson&token= I get ...
14
votes
3answers
875 views

Using GIS tools for non-geographical problems

Many other fields have visual/"spatial" problems that can potentially be solved with GIS tools. I know I've used GIS tools for the odd non-geographical task and was wondering how much this happens and ...
4
votes
1answer
288 views

Identifying south facing mountain land, above an elevation, within a slope range, less than fixed distance from major roadways

This odd question comes from believing that such an analysis is plausible in a GIS system. Only, I don't how to accomplish the various discrete steps implied from the Title, nor where to get a topo ...
2
votes
1answer
36 views

How to compute areas where the value in one layer is smaller than in another layer?

I have two vector layers, one contains actual values (in this case % cover of native species), the other contains target vales of the same attribute. the polygons are not always of the same geometry. ...
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0answers
50 views

Finding depressions in LiDAR DTM? [duplicate]

I would like to find temporary moist areas based on terrain surface shape (depression) directly from an airborne LiDAR DTM. Could you help me to find some tools or algorithm to solve the task?
3
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1answer
80 views

How to perform tree birthrate and mortality research with GIS [closed]

I'm using QGIS 2.6 and have 4 layers of polygons. Each of these polygons describes the outline of a tree, based on airborne imagery. My goal is to find the relations between every synchronously ...