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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24 views
Nearest neighbor analysis not showing results
I'm trying to do a nearest neighbour analysis on fish shoals distribution.
I go to Vector > Analysis Tools > Nearest neighbour analysis. I choose the appropriate layer and when I hit ok the black ...
4
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0answers
45 views
Point and Line Statistical Analysis
I have just lost the past 8 hours on this, and literally getting nowhere - hoping someone can help before I go mad!
I am trying to determine the correlation between sinkholes and a number of ...
2
votes
2answers
31 views
Solar analysis; Are there any issues with splitting large DEM
I am trying to run Solar analysis in ArcGIS and it is an enormous DEM of a very mountainous region. I'm obviously going to have to split the DEM, but I was wondering if there are any issues with ...
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1answer
34 views
territory analysis
I want to determine the territories in which customers to a bank has the shortest path. It can be done with desktop software packages or programming if it is needed. Does anybody has idea on how to ...
1
vote
1answer
43 views
Python GDAL: find out spikes and pits in DEM
I'm working with on a DEM (Geotiff) in Python GDAL, and I'd like to find out the spikes or pits in my terrain.
I have no idea how to proceed, does anyone have good algorithm to help me out?
Thanks,
eo
...
3
votes
2answers
96 views
Hillshade for 30m NED at continental scale
I'm new to terrain analysis. I have a 30m NED DEM (.tif) for the conterminous US. I would like to generate a nice looking hillshade for the US, but it looks bad - as in pixelated and rough (See ...
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2answers
56 views
Find and list all polygons that overlap with another polygon
I am working with two polygon layers which overlap but are unrelated (one is congressional district boundaries, the other is MPO area boundaries).
I would like to generate a list of all the ...
3
votes
2answers
62 views
How to computational efficiently check if there are any overlapping polygons in a group of polygons?
I need to do some processing with groups of polygons. If any of the polygons in the group overlaps other polygon the result is unpredictable and don't throw any error. So, I need to detect if there is ...
4
votes
1answer
50 views
How to find the Closest Facility (euclidean distance)?
I have some facilities and incidents, and I want to find the closest facility for each incident. I've done it via Network Analyst (with a network dataset) but I'm wondering if you can do it with just ...
1
vote
1answer
66 views
Watershed Analysis using DEM [duplicate]
I stumbled upon your question regarding the mosaic feature in qgis, the thing is I'm also using Quantum and this is my first encounter with GIS this semester, so if you can please help me with a ...
0
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0answers
31 views
How to add attribute from analysis to database mySQL?
I need to prepare a GIS for a customer. They insist to use a MySQL-Database (not the best option, I know). They need to digitize some geometries (areas) and add some attributes. The geometries and ...
1
vote
1answer
56 views
Basic traffic volume map [duplicate]
I'm trying to map the volume of people traveling from various cities to popular mountain towns in British Columbia. I have a .csv containing the starting point, ending point and number of travelers. ...
3
votes
6answers
86 views
GIS used to analyse micro-environment
Can anybody give me some articles or show me some link where GIS is used to analyse and manage micro-environment, such as a college campus or a small locality. I need to do a project on ...
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0answers
34 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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votes
0answers
379 views
Sextane script error (os is not defined)
I want to build an analysis script using Sextante 1.0.9 on QGIS 1.8.0. I find an example script in Youtube. I tried this code but never worked always getting error. People say that Sextante is ...
2
votes
1answer
28 views
Clipping a buffer from network analyst shapefile to a base shapefile
I have exported my polygon shapefile which I got after I ran my Network Analyst into a shapefile. It has 6 buffer zones (delimited by time in increments of 10 minutes). When I check the attribute ...
1
vote
1answer
83 views
ArcMap 10.1 Spatial Join: 'Contains' and 'Within' question
I have two polygon datasets: electoral districts and postal code areas. I'm performing a spatial join to see which postal code areas are completely within a district (the area can touch the borders, ...
0
votes
1answer
42 views
Calculating sinuosity of a path with GME in ArcGIS 10?
Does anyone have any experience with pathmetrics in GME?
I would ideally like to use the old Hawths's tool "line metrics" for calculating sinuosity of a daily path but I have ArcGIS 10. I downloaded ...
14
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1answer
302 views
Heatmap algorithm to visualise point diversity
Can anyone suggest an algorithm to generate a heatmap for visualising point diversity? An example application would be for mapping areas of high species diversity. For some species, every single plant ...
7
votes
2answers
281 views
How to create noise maps? (open source or scripted in ArcGIS)
In a previous role I helped create Noise Maps for Northern England.
The predicted noise levels was done using the IMMI package (which I can recommend) and the cartographic output was done in ArcMap. ...
1
vote
1answer
49 views
Is it possible to Clip in ArcExplorer?
Is it possible to clip in Desktop Explorer? Or does anyone know of any Analysis Servers I can connect to to get it?
6
votes
2answers
320 views
How to analyze differences between two shape files and put results into a new shape?
I have two polygon shape files of the same region from two different years (1985 and 1997) and I need to analyse the differences between the two shapes resulting in a third polygon shape file ...
3
votes
1answer
62 views
Find out tight corners on roads
Problem:
How can I pinpoint tight corners on a road dataset that might cause longer/larger vehicles difficulty in driving around.
Assumptions:
Ignore turns into junctions. Just interested in ...
5
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4answers
168 views
Advice on choosing ideal software for consultancy
I am taking the step to start a small business consultancy using digital map technology to assist retail business to better understand their environment and make informed location based decision. My ...
3
votes
2answers
170 views
Can python read the value of a cell in a spreadsheet? [closed]
Can python read the value of a cell in a spreadsheet?
The simplest example would be a script that ran a buffer tool on a given shapefile.
For the distance parameter, instead of just using a number ...
5
votes
2answers
148 views
Spatial Analysis with Factors/Classifications
When doing analysis on spatial data with associated information that is numeric, it is possible to use techniques such as Kriging or Interpolation or Cluster Analysis to find out interesting ...
3
votes
2answers
79 views
Using the ArcGIS Local Routing Tool . . geoprocessing in the runtime
When I create a model in ArcGIS using the Network Analyst Tools, I am able to create Locations and make the Route Layer and Solve. However, I need to be able to add barriers as well as locations, ...
3
votes
3answers
199 views
Summing attributes intersected by under a radius
Apologies - new user.
I am working with QGIS on Mac OS X and with shapefiles downloaded from the US Census Bureau that show population data by state and by county.
How do I:
select certain points ...
2
votes
1answer
117 views
Raster Analysis - Identifying features from Raster
I have an IDW, tension spline and hill-shade rasters that show an archaeological landscape and from these rasters I want to identify new features which are seen in the landscape as depressions. And ...
4
votes
2answers
199 views
Which GIS best for this problem?
This problem is similar to retail presence optimization. I'd like to know which GIS's could help us do the following:
Given a set of point locations,
create a circle of radius n meters around each.
...
4
votes
2answers
1k views
How do you use GIS to detect percentage of Land Use Change
I am a student in GIS I have a dissertation about land use change. I have questions about using ArcMap 10 for this aim, how can using GIS to detect the percentage of land use change. For example we ...
1
vote
1answer
108 views
Analyse spatial data and extract results in tabular form in QGIS
I'm sorry if this question is badly framed, I only started with GIS and QGIS 2 days ago so I don't know any terminology yet - I'll try to explain as best I can.
I have 2 layers in QGIS (1.8, on ...
3
votes
0answers
321 views
Performing a Multicriteria Analysis Using Distance Along a 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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0answers
48 views
Interpretation of MODIS VCF Data, concerning walking distance analysis
I'm still working on my diploma thesis (must be one of the last ones in germany..;)) which deals with distance analysis. I want to model walking distances and cost paths affected by slope, vegetation, ...
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0answers
94 views
Where can one find GIS shapefiles for all of California's municipal jurisdictions (cities, counties, special districts, JPA, CFDs, etc.)?Edit
Cities and counties are easy but I've been digging a while for the other information and haven't had any luck. Particularly interested in water districts and some of the more major JPAs -- for ...
3
votes
2answers
275 views
Creating dynamic GIS charts in ArcGIS 10.1
I have generated a table which has road segments which get inundated during different flood events. I want to be able to add a pie chart to the map which shows that during each flood ARI (1y, 2y, 5y, ...
3
votes
0answers
174 views
How to estimate the average width of a sidewalk? [duplicate]
I have a table with two polygons representing urban block with and without the sidewalk: geomBlock and geomBlockWithSidewalk.
On my city we can approximate the polygons of geomBlockWithSidewalk to a ...
1
vote
3answers
175 views
Determining gradient of road segment
I've a shapefile of roads data. It contains information about terrain of road segments, i.e., hilly, flat, undulating, etc. I want to determine gradient of every road segment. I know this might ...
4
votes
6answers
566 views
How to calculate the maximum distance within a polygon in x-direction (east-west direction) in PostGIS?
I am interested in the maximum width of a polygon, e.g. a lake, in the east-west direction. Bounding boxes will help only in simple polygons but not in complex concave polygons.
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vote
0answers
78 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 ...
2
votes
1answer
97 views
How can I estimate kernel density, taking barriers (i.e. a priori zero-probability regions) into account?
How can I estimate kernel density, taking barriers (i.e. a priori zero-probability regions) into account?
At the moment, regions where the population cannot occur are clipped out for display. ...
1
vote
1answer
128 views
2
votes
0answers
126 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 ...
2
votes
1answer
435 views
Modelbuilder - Feature Dataset Iterator
I had posted this on the ArcGIS forums, but thought I may get some further input here.
Having issues acquiring the appropriate input and erase features during the iteration process.
Please see ...
1
vote
0answers
148 views
mean coordinates in qGIS
I am using qGIS v 1.7.4 for MAC and trying to calculate mean coordinates for a set of points using ftools.
To calculate my result I am going to Vector -> Analysis tools -> mean coordinates and ...
11
votes
1answer
328 views
QGis raster terrain analysis - The curvature filter puzzles me
I am a french Master student at university Grenoble INP, and during my master project I have worked on DEM (raster) terrain analysis. Thus, I have read the source code of several QGis-1.7.4 raster ...
8
votes
2answers
230 views
Finding polygons without right angles
Now we are digitizing some buildings in specified area. The obligatory rule for this work - in most cases buildings should have right angles. We are using QGIS with CAD tools for this work. But ...
1
vote
0answers
84 views
how to set in arcgis network analysis that use every road segment max m times?
excuse me if my english ins't good. I have one incident and 120 facility. i wanna set criteria in Arcgis network analysis that if any road segment used for example m times, for other route doesn't use ...
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1answer
125 views
ArcGis - batch frequency of point groups to single table?
I'm kind of new in the GIS world but have been finding my way around in forums and help places up to now. Still, there's one task I need to perform that I cannot get my head around it or even find ...
2
votes
1answer
580 views
Hotspot Analysis: Low Values showing as hotspots
Im running hotspot analysis on point data, attempting to examine pollution emissions. I ran spatial autocorrelation first in order to determine the default distance threshold to use in the fixed ...
