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
2answers
134 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
78 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
91 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
45 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
145 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
76 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
2k 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
109 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
99 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
597 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
7k 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
110 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
160 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 ...
4
votes
2answers
394 views

Identify cluster centroids

I have a data set of points which are grouped into clusters like so: I'd like to use ArcGIS or Python to create a point layer of the centroids of each cluster but I can't seem to find the right ...
0
votes
1answer
354 views

How to colour contour lines in .shp file when the lines are not meeting in QGIS?

I am doing bathymetry analysis, where I would like to color the contours one by one in the case land is rising (or sea level going down). There is a comprehensive explanation about coloring contours (...
2
votes
0answers
240 views

FME - Raster Algebra and Multicriteria Analysis

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. ...
2
votes
1answer
207 views

How to dissolve adjacent parcels by same owner but include those parcels located across the street with the same owner?

In trying to determine the total contiguous stream length per landowner, I dissolved parcels by parcel owner name attribute and intersected these dissolved parcels with streams. However, dissolving ...
1
vote
0answers
147 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 ...
0
votes
0answers
239 views

Finding shortest cumulative route (i.e. best 'hub') between networked points

How do I find the shortest cumulative route (i.e. best 'hub') between networked points? I have a dataset where some but not all of the points in the network connect to each other, however it is ...
3
votes
0answers
140 views

How to create cost surface for least cost water transport analysis?

I am working on a project to derive least cost pathways between sites by dug out canoe travel. Has anyone worked on a similar project or found a function like the Tobler hiking function that can be ...
1
vote
0answers
43 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 ...
11
votes
1answer
841 views

When dealing with rasters of varying resolutions should one resample to the highest or lowest resolution?

I'm looking for recommendations on best practices for dealing with raster data layers with different resolutions and projections. The advice I've been given is to always resample to the layer with the ...
3
votes
2answers
58 views

What type of remote sensing methodology is commonly used to locate and track the movement of woodland caribou herds?

I am most curious whether it is possible to use Landsat or other freely available imagery (but info on any other method would great as well) to locate and track the movement of woodland caribou herds ...
1
vote
1answer
234 views

Calculating distance between borders when one polygon inside another polygon?

I am brand new to ArcGIS and having some trouble. I would like to calculate the distances between the border of one polygon to another polygon. However, these polygons overlap. Thus when I use the ...
1
vote
1answer
1k views

ArcGIS “Zoom to layer” scale

I'd like to quickly inspect the features in a feature class by double clicking the row in the table view and looking at the surrounding base layer. This works, but the feature fills the screen, so I ...
1
vote
1answer
139 views

How does the tolerance influence QgsGraphBuilder and tieing of points?

I am developing a script which uses OpenStreetMap data to calculate the distance (over the road network) between each building and the nearest hospital. To do this, I mainly follow the official ...
1
vote
3answers
1k views

Creating flat end type polylineline buffer in model without ArcGIS advanced

I have a polyline split into many short segments and would like to create a flat end buffer for each individual segment (not "dissolve" them all into one feature). Is there any way to do this in an ...
3
votes
2answers
1k views

Creating square buffer in qgis

How can I create a buffer with square ends along a line segment in qgis? I've buffered lines using v.buffer in the GRASS plugin, but the -c option for square ends is not exposed in that interface. ...
2
votes
0answers
102 views

Finding obstructions along a stream with LIDAR [closed]

I'm trying to find obstructions to boat traffic (downed trees, collapsed bridges, etc) along medium sized streams (5-15m across). The obstructions may or may not obstruct water flow. I have good ...
2
votes
1answer
379 views

Combining and displaying demographic data?

I am currently undertaking a demographic research project for my employer. We have the data on income, age, sex, language, transport etc and I have mapped most of it and created some thematics of said ...
3
votes
1answer
175 views

Add more info in the attribute table after executing “Line intersection” in QGIS

I have executed the "Line intersection" tool on a road shapefile. This is under Vector > Analysis Tools > Line intersections. I get an output with attribute table having just two columns: type_1 ...
25
votes
4answers
4k views

What are the benefits of hexagonal sampling polygons?

I am always on the lookout for useful methods to sample or partition study areas (usually in the form of raster datasets) into smaller units. Recently, I read an ESRI blog post about a new tool for ...
-1
votes
2answers
278 views

How to get layer extension info via Arcpy

I want to get file format of a layer with using Arcpy. I am writing a tool that needs to take raster or feature extension like SHP, TIFF etc. Which functions should i use ? Note: I use ArcGIS 10
6
votes
1answer
928 views

What is the FME Equivalent to the ArcGIS Union tool?

I'm attempting to union 2 large featureclasses in ArcCatalog, QGIS, and FME. What is the transformer that would be equivalent to the ArcGIS Union tool?
2
votes
1answer
489 views

GTOPO30 Slope analysis in ArcGIS 10.1 [duplicate]

Using surface - slope analysis tool box. All values for the slope calculation are in between 80 and 89. There are no values below 80. What am I doing wrong?
2
votes
0answers
244 views

Our best table-analysis with GIS? [closed]

Sometimes I think about possible analysis using GIS models (I use QGIS 1.8), and I always think about few types of visualization techniques: demographics, traffic flows, distance ones... Thanks to ...
2
votes
1answer
120 views

How to select a part of a land cover type a certain amount of feet away from another land cover type

I have raster Landcover type Urban combined with Forest all within the county raster perimeter. I want to make a layer of only the forest cells that are more than 500 feet from an urban cell, so that ...
0
votes
0answers
320 views

Linking two Models together in ModelBuilder

I am trying to link two separate models that iterate thought two different feature classes together into one, however I am having a small issue. When I bring in the sub-model into the larger one it it ...
2
votes
1answer
191 views

Is it possible to automatically update a Buffer FeatureClass when creating new features?

Is there a way I can update the results of my Buffer analysis? I have a roads FeatureClass, and I've built a buffer for it. I will still make edits to the road FeatureClass. Let's say I add a new ...
5
votes
1answer
2k views

Split polylines at polygon boundaries in QGIS

I have a set of contour lines and a polygon set containing glaciers. Because I want the glaciers to have blue contours, I need to split the contour lines at the glacier boundaries. I can achieve this ...
3
votes
1answer
883 views

how to calculate the basin length - which point to which point and how in arcgis 9.3?

This is the area of my research.I have calculated area using area and perimeter using arcgis 9.3 for doing morphometric analysis of the area.but i dont know how to calculate the length of the basin ...
3
votes
2answers
8k views

Reading National Elevation Dataset (ArcGrid/GridFloat/IMG) with python only tools

I've found high precision elevation (1/3 - 1/9 arcsecond resolution) data from the National Elevation Dataset provided by the USGS. It comes int IMG, Arcgrid, and GridFloat formats. I know ArcGrid ...
4
votes
2answers
2k views

What are some user-friendly GIS alternatives to Alteryx and ArcGIS?

I'm posting for some inspiration. At my last workplace we used Alteryx extensively for all data analysis, pumping out shapefiles which we'd then symbolise and output maps in ArcGIS. In my new ...
6
votes
2answers
185 views

Finding lines in point patterns?

I have a point pattern (see below) in which I assume to find "significant" lines of points. However, I did not find any method that is integrated in a GIS or in R that searches for such line pattern ...
1
vote
1answer
85 views

Counting and sum by two layers

I´ve got to layers, both polygons. Layer 1 consists of propertiers, where ID is individually names. Layer 2 consists of lakes. The query I want is: Total count of squaremeters of lakes for each ...
1
vote
0answers
464 views

Calculating walking routes along a network(ArcGIS)

I've created a network consisting of footpaths, dirt tracks and junctions. I would like to calculate a route using network analysis by giving ArcMap the time and walking speed that the route should be,...
2
votes
1answer
157 views

How to aggregate values multiple from multiple points along a route as an attribute of it?

I have a route network with a "Name" field that identify every route. On the other hand I have a shape file of points. Each point corresponds to the number of people using a route at a time t. I would ...
3
votes
1answer
378 views

Sensitivity analysis for coarse scale GIS epidemiological model?

I am working on an epidemiological model with disease incidence rate as dependent variable and environmental factors as independent variable. Disease data is available at county scale whereas ...
16
votes
1answer
381 views

What GIS analysis techniques were used in determining Gale Crater as the landing site for the Curiosity Rover?

What specific GIS analysis was used in determining Gale Crater as the landing site for the Curiosity Rover? I'm assuming factors such as slope, elevation, ruggedness, etc were used as well as ...
2
votes
1answer
267 views

Right raster zonal statistics for NDVI at county scale?

I am currently doing a modeling project at county scale in which I have disease rate as dependent variable and environment variables (such as temperature, NDVI and evapo-transpiration) as the ...