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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2
votes
2answers
423 views

SPOT NDVI time series

I have 423 spot.vgt ndvi from first April 1998 till 31 Dec 2009. I want to know how to stack these NDVI to have one image for time series analysis? Or better to ask how is it possible to analyze a ...
1
vote
0answers
285 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 ...
5
votes
1answer
2k views

ArcGIS - make linear regression across multiple raster layers

I have a series of 5 rasters which represent a value for 5 consecutive years. Is there a way to create a linear regression for each cell over the 5 layers and output the slope? The result would be a ...
1
vote
1answer
543 views

Volume of Land Below Sea Level

How could one use a GIS (or other appropriate system) to calculate the change in mean ocean levels across the world if all the land below sea level were flooded (Death Valley, Caspian Depression, Afar ...
1
vote
0answers
1k 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 ...
4
votes
0answers
2k views

Finding the “center of gravity” of multiple points where points have unequal weights [closed]

I'm trying to reduce a set of lat/lons (each with it's own weight) into one lat/lon that is the center of mass of all of the points. however when I map the results the average point falls no where ...
0
votes
1answer
366 views

Using ArcGIS 10 to find areas of overlapping use and areas with low use?

I have a spatial data set that shows areas of use (several different types of use) on the landscape. I am looking for ways to overlay these spatial use layers so that I can show where the areas of ...
1
vote
0answers
193 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 ...
0
votes
1answer
712 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
votes
0answers
403 views

How to analyse correlations between variables and points? [closed]

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
108 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 ...
0
votes
2answers
142 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
295 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
391 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 image)....
2
votes
2answers
4k 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 ...
5
votes
4answers
892 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 ...
2
votes
1answer
3k 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 ...
1
vote
1answer
126 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
337 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 micro-...
1
vote
0answers
72 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 ...
2
votes
1answer
97 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 ...
4
votes
1answer
2k 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
673 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 ...
15
votes
1answer
2k 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 ...
8
votes
2answers
6k views

Creating noise maps using ArcGIS for Desktop or Open Source Desktop GIS?

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. ...
7
votes
3answers
14k views

Analyzing differences between two shapefiles to put results into new shapefile?

I have two polygon shapefiles of the same region from two different years (1985 and 1997) and I need to analyse the differences between the two shapefiles resulting in a third polygon shapefile ...
4
votes
2answers
191 views

Finding tight corners on roads using ArcGIS Desktop?

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 ...
3
votes
2answers
1k 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
794 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
281 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, ...
4
votes
3answers
2k 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
349 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
245 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. ...
3
votes
2answers
7k 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
236 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 Win7),...
3
votes
0answers
914 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, ...
3
votes
0answers
194 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
4answers
911 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 ...
8
votes
6answers
3k 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.
1
vote
0answers
123 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
229 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. However,...
1
vote
1answer
2k views

How to compute mean coordinates?

Can anybody explain how to compute mean coordinates? Regards.
2
votes
0answers
537 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
0answers
622 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 ...
11
votes
1answer
682 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
648 views

Finding polygons without right angles using Open Source GIS or ArcGIS for Desktop?

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
1answer
326 views

Batch frequency of point groups to single table in ArcGIS Desktop? [duplicate]

I'm new in the GIS world. I have a bunch of points (around 40,000), which are split in categories (1 to 9) and have a field which specifies their membership to a polygon (~50) (e.g, 30, which would ...
10
votes
5answers
3k views

Multicriteria Analysis : how to?

I have to do a multi-criteria analysis to answer the question : "which is the best lot to develop". A few of the criterias are : distance of the nearest bus stop (point layer with bus stops) ...
2
votes
1answer
497 views

How to calculate the Zone of Impact using OpenWind

After downloading OpenWind, I am trying to calculate the ZVI for a single Turbine. There is no documention regarding this from the developers. At this point I just want to compare the output of the ...
10
votes
1answer
544 views

Looking for a trajectory similarity measure

For my final academic work I have developed a compression algorithm for GPS trajectories. I can estimate the quality of the spatio-temporal compression by computing the syncronized euclidean distance (...