The practice or science of collecting and analyzing numerical data in large quantities
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0answers
5 views
Reshape Matrix and perform Zonal Statistics in Matlab
I have 2 grids: 1) n by m - at 100m 2) n*10 by m *10 - at 10m. These grids cover the same area.
I have to perform zonal statistics at scale of grid no.2. Cell value of grid no.1 is cumulative for ...
1
vote
1answer
22 views
Why does the Zonal Statistics tool always return 0?
I have a slope raster created from a DEM raster with the DEM Analysis tool.
Now, I would like to calculate the average slope in a given area represented by a vector polygon layer.
I thought I could ...
4
votes
0answers
44 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 ...
1
vote
0answers
21 views
How to join two fields after calculating ?
I have been working with two layers and I am trying to join them and turn them into a raster data. The first layer is a watershed layer which I have assigned each shed a location from the center point ...
1
vote
0answers
18 views
QGis Grid statistics for polygons error - Module caused access violation!
I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log ...
0
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0answers
27 views
Area statistics in Qgis
I just want your help to summarize areas in two levels; firs level is in a field (Municipalities) and in other field I have Has and finally a third field "values" that came from a raster, the values ...
0
votes
0answers
24 views
basic statistics in qgis lisboa doesn't work under shapefile
When I add csv file and the basic statistics works well, after I save it as shapefile, and the basic statistics doesn't work properly under shapefile, why?
2
votes
3answers
111 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 ...
1
vote
1answer
34 views
r.regression.multi - ERROR: Not enough valid cells available
I am running a few analyses with r.regression.multi in Grass 7. For a few rasters that I try to correlate, the following error comes up, however: "ERROR: Not enough valid cells available".
I cannot ...
0
votes
1answer
49 views
min and max values are not correctly calculated for DEM
I'm working with DEM in QGIS and need to know the min and max values of my data.
In the Properties window, under the Metadata tab, the statistics section shows such values. However, I usually find ...
1
vote
1answer
44 views
Grass7 - r.regression.multi and new raster
I am on the learning curve with Grass7. I managed to make r.regression.multi work, but there is one thing that would be of high interest for me: it is possible to create a new raster showing the ...
0
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1answer
38 views
Grass 7 - where is r.regression.multi hiding?
I compiled Grass 7 on Ubuntu and all works fine - except, I cannot find r.regression.multi. I installed it, yet it is nowhere to be found in the drop-down menus; r.regression.line is there and works, ...
0
votes
0answers
22 views
Zonal statistics-troubleshooting
I am using ARCGIS 10.1. I am trying to calculate zonal statistics using as feature zone the world borders (http://thematicmapping.org/downloads/world_borders.php) and as input raster ...
0
votes
1answer
47 views
ArcGIS Statistics tool problem
I have an excel file for average rainfall by month and I added that on ArcMap. while I tried to check the statistics the tool is passive for last 3 months and I checked the data on arcmap, they are ...
1
vote
1answer
76 views
raster statistics - regressions between raster data
I have the following problem:
I have two set of rasters, with data that should correlate...one are measured data, one are modelled data. The correlation is weak, however, when looked at with a normal ...
2
votes
1answer
66 views
Raster export for regressions analysis
I have the following issue:
I am trying to do a regression analysis between the (z) values of two rasters. What I would ideally like to have is the raster output not as grid but rather a list of ...
2
votes
1answer
62 views
Relationship between attribute of vector data and raster variable in ArcGIS
I have a vector data of individual elements (buildings) with attributes (value, etc), and several raster grids with continuous variables. I would like to understand whether there is a relationship ...
0
votes
0answers
31 views
How to extract high frequencies from a point shapefile?
I need to get the average of the 3 highest frequencies in a table and append it to a shape file i already have
hope you can help me
3
votes
1answer
55 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:
...
4
votes
2answers
110 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
...
3
votes
1answer
47 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 ...
2
votes
1answer
43 views
Create ERDAS IMG Statistics using GDAL C++ API?
I want to create very many ERDAS .img files using GDAL under C++. I don't want to have to process them all in ArcMap to create statistics for them (mainly because ArcMap fumbles when calculating ...
2
votes
1answer
72 views
Error 010240 with ZonalStatistics
I have a code that calculates the sum of water recharge for a pixel for a 9 year period (This piece of code works fine, just thought I would show how it is made just in case. The values range from 0 ...
2
votes
1answer
95 views
Accounting for Spatial Autocorrelation in ZINB Model?
I'm doing an analysis on disease in Chile. I'm using the rate as the Dependent Variable and both remote sensing and housing-type data as the Independent Variables. I have several questions regarding ...
6
votes
2answers
296 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. ...
2
votes
1answer
94 views
STATISTICS not allowed in the Attribute Table
I created a shapefile, calculated geometry then went to grab the stats, the statistics was ghosted, not allowing me to grab those numbers. I am using 10.1 ArcView.
I deleted the field and created a ...
3
votes
1answer
77 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
157 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 ...
5
votes
1answer
235 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 ...
0
votes
0answers
115 views
How to Chart Frequency Distribution in ArcGIS using VBA or Python? [closed]
I am looking to find the code ( VBA OR PYTHON ) or any programming language for statistics frequency chart field ( like arc GIS one)... I didn't find any code to how I create the chart statistics from ...
3
votes
2answers
169 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!
5
votes
2answers
845 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 ...
2
votes
1answer
394 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 ...
1
vote
0answers
129 views
Using R data to make histogram in ArcMap
I am writing a tool in python which passes parameters to a R script, which in turn creates a DBF file. I read this DBF and want to make a histogram out of the data inside ArcMap as one of the results ...
1
vote
0answers
224 views
Stats problem, QGIS heatmap [closed]
I am new to QGIS 1.8 and have been trying to make a heatmap. From what I can tell, the reason I am not getting the results I want is that the max value of the raster is erroneously measured at 2. ...
2
votes
0answers
125 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
41 views
What is the method for finding the percentage of common cells among 2 or more DTMs for the same area?
I have a study area and 6 different DTMs for that area from different sources and I would like to know the percentage of pixels with the same value. I suppose I will have to extract some statistic and ...
3
votes
1answer
701 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 ...
6
votes
3answers
503 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 ...
11
votes
7answers
957 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?
3
votes
1answer
321 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 ...
0
votes
1answer
310 views
Testing if shapefiles intersect from a list using intersect: ArcGIS
I am new to programming and scripting in general, so please bear with me. I have generated a list of the location of all the shapefiles for my workplace. The files are all placed in folders, no ...
9
votes
5answers
2k 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 ...
6
votes
3answers
2k 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 ...
0
votes
0answers
51 views
How to calculate sums for all fields in a table? [duplicate]
Possible Duplicate:
are there any methods can choose all field and make the SUM for each fields or I must do it one by one?
Are there any methods that can calculate the summary statistic ...
5
votes
2answers
909 views
Frequency, summarize tool
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 ...
4
votes
1answer
381 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?
6
votes
1answer
95 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 ...
4
votes
2answers
686 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 ...
8
votes
2answers
210 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 ...
