Collecting and analyzing numerical data or making numerical summaries of data.

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15
votes
7answers
3k views

Best spatial statistics software for GIS?

I am searching for spatial statistics software which has many powerful features and supports a GIS interface. Can anyone give me some advice?
12
votes
5answers
4k views

Get Raster Values from a Polygon Overlay in Opensource GIS Solutions

I have two layers. A polygon-shape-layer with many tiles and a raster-layer containing CORINE 2006 land cover with many categories in a colourmap. I want to obtain for each polygon in the shapelayer a ...
11
votes
4answers
538 views

Math and Stat for GIS and Computing

I am planning to do an advanced program in spatial science and engineering. It states as a requirement in the program, that the student should have a through understanding in math and statistics. So ...
10
votes
3answers
472 views

How is margin of error reported on a map?

When reporting estimates you should always include the margin of error. There are conventional ways of reporting margin of error in a table, text or graph. But, how do you report margin of error for ...
8
votes
4answers
7k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
8
votes
2answers
464 views

How can I find the median column in a database?

I have data on period of construction for dwellings in dissemination areas. I have transferred this data to my study areas and would like to determine the median period of construction for each study ...
8
votes
2answers
217 views

spatial and spatiotemporal analyses

I have a dataset that consists of 247 mosquito traps placed in fixed positions and sampled weekly for 23 weeks. I also have dengue disease incidence data (indexed to home address) during the same time ...
7
votes
1answer
3k views

Are there QGIS tools that will allow users to get tabular statistics from their table?

Are there QGIS tools that will allow users to get tabular statistics from their table? I kind of expected I would be able to just open the table, select the field I was interested in, right-click on ...
7
votes
1answer
2k views

How to get GDAL to create statistics for GTiff in Python

I regularly create my own GeoTIFF rasters with GDAL in Python, e.g.: from osgeo import gdal from numpy import random data = random.uniform(0, 10, (300, 200)) driver = gdal.GetDriverByName('GTiff') ds ...
7
votes
2answers
4k views

Calculate area of intersecting polygons in QGIS

I have two collections of shapefiles: 1 - postal codes, administrative and political areas 2 - various land use categories like parks & allotments, and points like trees I want to produce ...
7
votes
3answers
541 views

How to use ZonalStats plugin?

I am using QGIS 1.8.0 on a Windows Home Premium 7 machine. I have a single band TIFF that is 187 MB in size. My vector polygon shapefile represents a regular grid of a 147x112 36kmx36km grid cells. ...
7
votes
1answer
171 views

Graphically depict statistical difference between thematic rasters

The graph shows a regression between two raster datasets with classified tree canopy cover: class 1 = 0-10%, class 2 = 10 - 20% ...class 6 = >60% (Figure 1, Figure 2). The spatial resolution for ...
6
votes
2answers
2k views

Is it possible to access ArcGIS's table operations “Summarize…” and “Statistics…” in python?

ArcGIS has a few nifty table tools, including Summarize and Statistics. Is there a way to access them through arcpy, or will I have to hack my own methods via math and lists?
6
votes
4answers
2k views

How to sum up pixel values in QGIS?

I need to know the value of the sum of all pixels in a raster. However, in the Statistics section of the Metadata tab in Properties, under Sum of All Cells it always indicates 0.00. I have tried with ...
6
votes
1answer
115 views

How can I generate a range of pantones for a map?

When I am given a map (or make one...) I often like to get an idea of the range of colours present. One thing this does is it allows me to quickly visualize contrast (helps build maps for colour blind ...
6
votes
1answer
1k views

ArcGIS median value from a layer

I've been hunting around ArcGIS 9.3 and having no success at finding a tool/function that can give me the median (not the mean/avg) tabular value of a spatial database. For example, if I have a data ...
5
votes
2answers
2k views

Frequency, summarize tool options of ArcGIS for Desktop?

I'm looking for some general frequency, summarize tool. What I basically want is some tool like the summarize tool in ArcGIS (right click in the attribute table> summarize) that runs on all attributes ...
5
votes
3answers
184 views

Is it possible to calculate statistics across multiple fields in arcpy?

The summary statistics command can be used in arcpy to calculate statistics - this tool runs against a single field, eg: SUM—Adds the total value for the specified field. Is there an ...
5
votes
2answers
169 views

Different models, different contours: are they comparable?

I will get contour lines of electromagnetic field strength around power lines. The contours will be calculated by different agencies using different models. We need to check whether the resulting ...
5
votes
1answer
445 views

QGis Zonal Statistics Plugin NoData included in Calculations

I have been trying to use the QGIS zonal statistics plugin. My raster has a nodata value of -99999 and all other values are positive. After computing the mean zonal statistics there are a number of ...
4
votes
3answers
1k views

How to count occurrences of one field grouped by values of another?

Is there a way of calculating the number of unique text strings in a field in ArcGIS 10.1? I have a number of repeated strings in this field, but would like to calculate the number of unique strings ...
4
votes
1answer
675 views

How to use/interpret/visualise a distance matrix with unknown coordinates?

How would you go about using a distance matrix where points have no coordinates, i.e. what useful statistics can be made and how to visualise it in some useful way?
4
votes
2answers
3k views

Is there a zonal statistics tool to calculate median and mode raster values for each polygon?

I'd like to calculate zonal statistics for a raster where the zones are defined by polygons in a vector layer within QGIS. Specifically I'm interested in calculating the median and mode raster values ...
4
votes
1answer
172 views

Why covariance values are different in R and ArcGIS?

I've calculated covariance between 7 rasters using R and ArcGIS. It gives me different results. Each times covariance values from R are approximately 1.874 times higher than ArcGIS values. R - ...
4
votes
2answers
1k views

GDAL does not ignore NoData value

I am trying to calcualate the statistics of a TIFF. The script should ignore the NoData value, but doesn't. What causes this? import gdal from gdalconst import * # register all of the drivers ...
4
votes
1answer
3k views

How to detect duplicate attribute values in a table using ArcPy

In ArcMap, the right-click Summarize option very quickly creates a frequency listing of the chosen field: Note that the count field shows the count of duplicate values. How can I access this ...
4
votes
2answers
609 views

Zonal statistics for millions of overlapping polygons

I am running ArcGIS 10.1 with 64-bit GP on Windows 8.1 x64. I want to calculate the zonal statistics of buffer polygons based on parcels and a kernel density raster. The 4.7 million polygons overlap ...
4
votes
1answer
27 views

raster statistics by line shape (vector)

I have a georeferenced area where I created 7 raster maps (classified with suitability values from 1 to 5) as I have 7 factors to check e.g. natural reserves, floods, slopes etc. From there I did a ...
4
votes
1answer
97 views

How to get counts from a table to produce a heatmap?

I am trying to create a heat map of doctors per zip code based on zip code. I have a table with the doctors and their zip codes, some of them repeating because there is more than one doctor per zip ...
4
votes
3answers
1k views

Calculate neighborhood statistics for polygons?

I've been searching around for the answer to this (including here) and have yet to find it. I'm interested in finding out how to calculate a 'neighborhood sum' for vector, polygon data. I am aware ...
4
votes
1answer
251 views

How to create Series of Rasters that displays Standard Deviation from Mean?

Cell statistics question for you. I have 100 rasters of raw rainfall data in which the pixels each represent rainfall for that particular pixel on the landscape for a single year during the 100 year ...
4
votes
0answers
281 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 ...
3
votes
1answer
700 views

Why are the results from the same data different in ArcGIS vs MS Excel?

I have done some interpolation in Geostatistical Analyst in ArcGIS and I got the Standard Deviation (SD) a bit different from the SD that I calculated in Excel Spreadsheet. What algorithm does each ...
3
votes
2answers
329 views

Performing statistical analysis of buffers?

I am doing a buffer analysis of incinerators and looking at the output areas within those buffers, is there a way of doing a statistical analysis of several buffers to see if there is a significant ...
3
votes
2answers
136 views

Methods for hot spot or cluster analysis for multiple measurements at the same geographic unit?

I would like to find geographic clusters of zip codes where each zip code has a measurement of a person's age (integer), sex (categorical/binary), and if they recovered from a certain medical ...
3
votes
2answers
367 views

How are kappa and overall accuracy related with respect to thematic raster data?

I recently calculated kappa (using confusionMatrix{caret} in R) between a thematic raster dataset at 1m spatial resolution and another at 30m spatial resolution. I was interested in quantifying the ...
3
votes
2answers
670 views

How to create a standard deviation map from three rasters in QGIS?

I have 3 normalised (0-100) raster maps. Is it possible to get a map which shows the standard deviation? I'd like to see the areas with smaller and higher std deviation. Thank you!
3
votes
2answers
798 views

How can I track/graph arcserver usage statistics?

I’m currently using the ArcGIS Server Properties dialog in ArcCatalog to periodically check the usage statistics for our services. I’d like to be able to chart those to get a big picture view of ...
3
votes
1answer
77 views

How to make zonal statistics model more efficient?

I've made this model, to assess some 500-600 rasters for one area, and spit out one huge table. So far, when testing it with 20-30 rasters as inputs it works, but now that I put in the full amount its ...
3
votes
1answer
318 views

How to create a x-y scatterplot from attributes in QGIS 2.0?

There are a few old packages that allow the creation of x-y scatter plots from attributes in vector data (Scattergram for 1.7) http://plugins.qgis.org/plugins/scattergrammidentify/ (SPQR for very ...
3
votes
1answer
284 views

Setting Band Statistics on Raster Image (GeoTIFF)

After doing calculations on a raster and saving it, the image statistics are wrong and need updating. I find examples saying that this should do the job, like in this example: ...
3
votes
1answer
115 views

Calculating Percentiles in ArcMap?

I have a large polygon dataset (26,000) records with numerous attributes columns. I wish to calculate the percentile rank of each attribute. Say I have population_density in an attribute, is there a ...
3
votes
1answer
498 views

PCA on correlation matrix in ArcGIS

I am trying to run a PCA on a set of normalized raster bands within ArcGIS. I would like to calculate the PCA on the correlation, not the covariance, matrix of the PCA, but Arc as far as I can tell ...
3
votes
1answer
305 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 ...
3
votes
1answer
57 views

World territorial units for statistics

My current assignment required to do research and produce world territorial units for statistics. In Europe it easy thanks to Eurostat. Even non-commercial GIS data is also available here. Now ...
3
votes
1answer
848 views

API for Real Time World Statistics

Does anyone know of an API (preferably free) that can provide real time world statistics such as Crude Birth Rate, Crude Death Rate, world/country population, or emails sent today as on the website ...
3
votes
2answers
1k views

How to find out the Basin Length?

I am doing Project on Drainage basin, to find out the Elongation ratio I need to find out Basin length, Can any one of you tell me how to find out BASIN LENGTH using ArcGIS or any other way. My data ...
3
votes
1answer
52 views

Cell Statistics in QGIS

Cell Statistics in ArcGIS will calculate the mean (or statistic of choice) among multiple rasters on a cell-by-call basis. Can QGIS do this? If so, how?
3
votes
1answer
325 views

How to sum up all field values in QGIS modeler

I am building a model to generate two zones around a point, a 250m-buffer, and a ring of 250 to 1000m, where i recalculate values from an other layer according to the intersections share. The purpose ...
3
votes
0answers
86 views

Zonal Histogram Output Problems - No values associated with the habitat type

I have a outline of some islands (shapefile or raster) and GAP landcover data (raster). I am trying to use Zonal Histogram to create a file with a histogram of the habitat types in each island. Each ...