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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3
votes
1answer
32 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 ...
1
vote
1answer
25 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
63 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 ...
0
votes
0answers
43 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 ...
0
votes
0answers
23 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 ...
0
votes
0answers
42 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 ...
1
vote
1answer
72 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 ...
1
vote
2answers
38 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, ...
0
votes
1answer
26 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?
2
votes
1answer
79 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 ...
3
votes
2answers
119 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
108 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 ...
-3
votes
1answer
61 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?
0
votes
2answers
35 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 ...
1
vote
0answers
50 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
vote
1answer
58 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 ...
1
vote
1answer
209 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" ...
0
votes
0answers
42 views

Obtaining NDVI data from selected area

I need to analyse NDVI (-1/1) change between years (05-10y). But still only under selected shapefile. To analyse the extent of each NDVI category. Any tips? I have tried to make vector from the NDVI ...
0
votes
0answers
14 views

implementing floyd-warshall in roadgraphplugin

I have to implement Floyd-Warshall algorithm in the road-graph plugin in QGIS. I have written the following code in qgsgraphanalyzer.cpp and qgsgraphanalyzer.h, and checked my output with the output ...
0
votes
0answers
30 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 ...
8
votes
1answer
267 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
vote
2answers
435 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
votes
1answer
248 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 ...
1
vote
0answers
143 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
264 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
votes
1answer
105 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 ...
1
vote
1answer
69 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
vote
1answer
144 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
152 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
816 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 ...
1
vote
1answer
45 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
803 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
215 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
35 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. ...
1
vote
0answers
39 views

findind depression in cloud point and dtm

I would like to find temporary moist areas based on terrain surface shape (depression) directly from cloud point data (ALS) and DTM. Could you help me to find some tools or algorithm to solve the ...
3
votes
1answer
79 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 ...
1
vote
2answers
474 views

How can I calculate how many of a certain feature lie within my various buffer rings?

I am using ArcMap and I have a series of real estate parcels mapped along with a series of wind turbines. I have created multiple buffer rings around each real estate parcel with distances (0.5, 1, ...
3
votes
2answers
114 views

QGIS calculates main soil type of polygons from another polygon layer

I've been working with qgis for a while but somehow I never fiured this out, so I thought it's time to ask. I have 2 shapefiles. a polygon layer from nearby fields (SHAPE1 (the red outlines)) a ...
1
vote
0answers
65 views

how to use line feature as stops input in network analyst?

I'm trying to build a certain route with network analyst on a Network Dataset. As an input to create the route I want to use line features. I am trying to do this with network analyst in ArcGIS 10.0 ...
1
vote
0answers
86 views

Get pixel values ascii 50 files

I´m working with photos from a cam. The cam 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. I am ...
2
votes
1answer
41 views

Clip_Management seems to delete shapefile?

We have some python code that clips a very large shapefile for further processing. We can see the process create all the output files, but then just as the process is finishing, they get deleted. ...
3
votes
1answer
117 views

Performing equivalent of ArcGIS Identity_analysis (line with poly) using PostGIS?

I've got a section of arcpy code that I need to port PostGIS: Identity_analysis with the in_features being a line featureclass and the identity_features being a polygon featureclass. I'm primarily ...
1
vote
0answers
63 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 ...
9
votes
5answers
1k views

GIS analysis to find duplicate geometries

I have a big shapefile that contains all the buildings and houses of the town that I work in (approx. 90,000 features). The data of the buildings/houses are saved by the town's surveying engineers and ...
0
votes
1answer
88 views

Looping Summary Statistics on changing field name

I am trying to calculate summary statistics for a number of shapefiles, which is easy enough, but the field name for each shapefile is different. The field name is identical to the file name if that ...
5
votes
1answer
86 views

Is it possible, and if so how, to effectively classify vegetation types using false near infra red imagery?

Background : I use near infra-red imagery to delineate wetlands and water bodies with good success. It's also obvious to distinguish between new healthy vegetation and older growth and land areas with ...
3
votes
1answer
388 views

How to batch process near feature distance in ArcGIS

I have 2000+ point shape files. These are all GPS tracks. I want to calculate the distance from each point to the nearest feature (road, train line, restaurant etc) within a 30 meter radius. I am ...
5
votes
2answers
5k views

Are GIS Analyst salaries going to always be so low? [closed]

I regularly see GIS Analyst job postings (often in very expensive cities) asking for a plethora of experience paying in the $40k - 60k a year range, many are even below $40k or $30k. Considering the ...
3
votes
1answer
96 views

Statistical Analysis of Shapefile Proximity within Raster Image - ArcMap10.1

I have a raster image that has been reclassified into 15 equally incremented values/levels. This raster represents "sinkhole risk" in a certain county. So level 1 is the lowest risk region and level ...
0
votes
2answers
134 views

Frequency analysis and overlay analysis

Am new to gis and I hope to find help here. I am working on a research that requires that I overlay conditions of drainage systems and quality of healthcare in a coastal state to get areas which have ...