Zonal statistics summarize the values of one raster within the zones of another dataset (either raster or vector) and output the results as a raster (for a single statistic) or table (for multiple statistics).

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7
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3answers
545 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. ...
6
votes
2answers
2k views

How to use QGIS Zonal Stats Plugin from Python Console?

I am using the Zonal Stats plugin in QGIS to extract raster statistics from overlaying polygons (I have shapefiles of species distribution and I want to extract environmental data from within each ...
5
votes
1answer
458 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
1answer
117 views

How are raster pixels determined whether they are in or out of a zone?

I just needed to confirm something that I think I already know the answer to because help pages are always unclear. I am running ArcGIS 10.2.2 and often use the Zonal Statistics and Tabulate Area ...
4
votes
2answers
671 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
48 views

Zonal statistics discrepency between Arc 10 versions

I've discovered a weird phenomenon using zonal statistics with a colleague at another office. We are attempting to use the Zonal Statistics as Table tool to sum the value of raster cells within ...
4
votes
1answer
130 views

Any way to perform zonal statistics on column other than value or do reclass faster?

I have to perform ArcGIS zonal statistics on a raster, but the column I am interested in is not the 'value' column. Now, I can reclass the raster so that the column of interest becomes the 'value' ...
4
votes
1answer
181 views

Is there an issue with Zonal Statistics calculating wrong mean values?

I tried to solve the following issue by myself but without success. On the one hand I have a raster file which is the result of the processing "shapes to grid" tool. On the other hand I have a ...
3
votes
1answer
235 views

Getting Zonal Statistics of Overlapping Circles?

I have a Buildings (polygon) shp file and a DSM. what I wanted to do was to get the pixel values for all the vertices of those buildings, and find another pixel value just around those vertices (say ...
3
votes
2answers
1k views

Issue Trying to create Zonal Statistics using Gdal and Python.

I am trying to create zonal statistics using Python and Gdal. I have a polygon shapefile and a raster file, and in order to do so, I am using a piece of code I found in StackExchange. The raster and ...
3
votes
4answers
74 views

Calculate minimum area where x% of raster value total is concentrated within polygons

I have a raster layer (chlorophyll concentration) and a layer of non-overlapping polygons (regions of the ocean). For each polygon, I'd like to calculate the area where the majority of chlorophyll is ...
3
votes
3answers
199 views

How can I determine which raster attribute covers the highest area of a polygon?

I'm relatively new to GIS and QGIS but I have a problem that I'm not certain how to solve. I searched here for relevant information but found none. (Or, I used incorrect search terms.) My problem ...
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
0answers
90 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 ...
3
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0answers
459 views

Extract values from raster based on weighted average area using polygon grid

EDIT: I am using Armap 10 sp 5 I have found similar questions but they were either unanswered or somewhat different to what I am asking. I have a raster with cell values 1-5 and a polygon shape file ...
3
votes
0answers
118 views

Tabulate Area using GDAL and Numpy

How could I perform a Tabulate Area using GDAL and Numpy? I am trying to summarize how many pixels of each class in a Landcover raster are within each polygon of a Census Blocks shapefile. I've ...
3
votes
4answers
3k views

How to read this data file and convert it to raster format for analysis?

I am trying to introduce the 5 degree dataset from here http://www.cru.uea.ac.uk/cru/data/precip/ (it is the first link). And once I introduce it to GIS to use it as a raster input to calculate zonal ...
2
votes
2answers
396 views

How to Calculate Custom Zonal Statistics?

I have a vector polygon shapefile outlining counties for which I have a raster of nighttime-luminosity data. I've been able to compute Zonal Statistics in ArcGIS 10.0 using Zonal Statistics as Table ...
2
votes
1answer
107 views

Find local maxima with variable window search using ArcGIS Desktop?

I would like to find local maxima in different zones of raster file. I got five zones (zone 1, 2,3,4,5) and would like to find local maxima with different window search for each zone in arcgis ...
2
votes
1answer
188 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 ...
2
votes
1answer
87 views

Monthly weather averages using NCEP/NCAR Reanalysis data

I'm a political science grad student and I've recently (and probably foolishly) committed to dipping my feet into GIS. Right now I need to build a table that has monthly precipitation and temperature ...
2
votes
1answer
61 views

Issues with PyQGIS while running a QgsZonalStatistics script

I have experienced a very bizarre issue with my PyQgis code. I simply want to load a raster and a vector layer to do zonal statistics, the first part works perfectly but for the zonal statistic I have ...
2
votes
1answer
92 views

Intersect shapefile with raster, then determine proportion of each raster value?

Using the arcpy module in Python, I want to find the proportion of each pixel value within the boundary of an overlaying polygon. (The polygon is in a shapefile.) For example, there are 10 possible ...
2
votes
3answers
149 views

Zonal Statistics as Table Tool

I have a slope dataset. I have a polygon shapefile with territory within the extent of the slope map. I have to calculate the real surface area of this shapefile using the zonal statistics as table ...
2
votes
1answer
89 views

How to loop qgis:zonalstatistics using Python?

I'm looking for some Python + QGIS foo for the following: import processing for i in range (1,20): processing.runalg("qgis:zonalstatistics", "/folder/input/raster.tif",%i, ...
2
votes
3answers
949 views

How to get count of non-NA raster cells within polygon using R

I've been running into all sorts of issues using ArcGIS ZonalStats and thought R could be a great way. Saying that I'm fairly new to R, but got a coding background. The situation is that I have ...
2
votes
1answer
276 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
2answers
2k views

Iterate through multiple Raster files and compute statistics using Zonal Statistics

I have a large number of raster images. What I'd like to do is to compute statistics on different sections of these raster files using a polygon. I think everyone is suggesting Zonal statistics. ...
2
votes
2answers
333 views

Tabulate Area crashes Python and ArcGIS

I have a script that runs Tabulate Area on a single feature class multiple times with different rasters. In total Tabulate Area runs 5 times. 2 of the input rasters are provided as arguments to the ...
2
votes
1answer
302 views

Zonal Statistics-Weighting

I have a raster file on precipitation and I want to create zonal statistics as a table using a shape file wiht boundaries of countries across the world. However it appears that I need to take into ...
2
votes
1answer
359 views

joining a table from zonal statistics as table with a layer, problem with reserved names

I have a raster file (percentage of total forest killed) and a shapefile with polygons (municipalities). I thought as a first step I would like to find out which municipality shows the greatest ...
2
votes
1answer
53 views

Memory issues with zonal statistics

I have got a memory issue due to the use of the zonal statistics command into a loop. It seems that after using the ZS command QGIS stores some information in the RAM (cache memory?). It is not ...
2
votes
0answers
59 views

Does converting polygon to raster generate more accurate results from the Zonal Statistics in Arcgis 10.2

I have heard the following for Arcgis 9.1 and wonder whether it is still an issue in Arcgis 10.2. If so, should I convert the polygon into raster before dissolve or convert the dissolved polygon ...
2
votes
0answers
78 views

Zonal Statistics Freezing QGIS 2.2

Running on Windows; 8gb memory, 500gb HD, i5 cpu; Raster file: 250mb I am having a problem with zonal statistics advancing past 17%. I am trying to run statistics on a crop grown in certain counties. ...
2
votes
0answers
232 views

Zonal Statistics using Gdal and Python

I recently came across a loop_zonal_stats function by @ustroetz found here: Issue Trying to create Zonal Statistics using Gdal and Python.. I am using a (single) polygon shapefile and a raster file to ...
2
votes
0answers
51 views

Wrong pixel sums within buffers in Esri ArcGIS 10.0

I have a raster of Zambia, 100m² resolution (about 650mb). Buffers (single) at 1,2,3,4,5,10,15,20,25,30,50 km. I'm running "zonal statistics as table" in the model builder for all buffers (actually, ...
2
votes
0answers
490 views

How to Calculate Utilization Distribution Overlap Index (UDOI) in ArcGIS

I'm interested in calculating the overlap of home ranges (=utilization distributions in my case) of a bird species using sighting coordinates. This article introduced UDOI as the best index for such ...
2
votes
0answers
295 views

How to use GRIB data in ArcGIS? (Zonal Stat as Table)

I am trying to calculate zonal stats as table with a python script for 45 .grib files from the ERA-40 Monthly Mean of Daily Mean database (http://data-portal.ecmwf.int/data/d/era40_moda/) for certain ...
1
vote
1answer
58 views

Overwrite option on a standalone ZonalStatisticsAsTable using ArcPy

How can I code an "overwrite option" on a standalone ZonalStatisticsAsTable using ArcPy? I don't see any overwrite option from a Esri example. # Execute ZonalStatisticsAsTable outZSaT = ...
1
vote
2answers
1k views

What to do when raster cell size is larger than zonal vector feature in order to collect statistics?

I am trying to extract the mean cell values for a raster dataset based on a survey grid polygon feature using ArcINFO 10.1. The cell size of the raster dataset is about 4 times the size of the survey ...
1
vote
1answer
282 views

How to create graph out of two layers using ArcGIS 10.1 for Desktop?

I would like to create a graph of two layers I have. on one hand its the land price of a certain area and on the other a layer with a crime rate. first of all, the layer with the land prices doesnt ...
1
vote
1answer
258 views

ArcGIS TabulateArea() :: Recommend Ratio of Zone Area to Value Raster Cell Size?

Any recommended ratio of zone area / raster cell size when running small input zones with ArcGIS Tabulate Area Tools? Esri mentions: If the zone input is a feature dataset with relatively small ...
1
vote
1answer
353 views

Is there a way to perform zonal statistics-like operations with feature zone data without doing feature-to-raster transformation?

I want to use zonal statistics on Chinese counties (which can be very small) from a fairly coarse (0.5 degree) raster grid. The problem with zonal statistics is that it returns a much smaller number ...
1
vote
1answer
22 views

Querying Raster Dataset by Location to Study Area

I have downloaded a very handy raster dataset generated by the Nature Conservancy for identifying terrestrial habitat cover types in the north east. Link to the project info and a link containing a ...
1
vote
1answer
257 views

Calculating real surface area using Zonal Statistics as Table Tool?

I have a slope dataset. I have a polygon shapefile with territory within the extent of the slope map. how do I calculate the real surface area of this shapefile using the zonal statistics as table ...
1
vote
1answer
198 views

What do “count”, “mean”, and “sum” in QgsZonalStatistics mean?

I am working with Qgis and making some analytics of lightdata. I've used these commands: rasterfile = qgis.utils.iface.mapCanvas().currentLayer().source() vectorlayer = ...
1
vote
2answers
33 views

How to define PROJ.4 string for GDAL projection

I'm doing some zonal computations in GDAL using the code posted in the solution here: Issue Trying to create Zonal Statistics using Gdal and Python. It runs fine for me using the example data posted ...
1
vote
1answer
166 views

Export “Zonal Statistics As Table” output in Modelbuilder

I have an extremely simple model that takes as input a shapefile for zones along with a value raster. All the model does is produce a table of my desired zonal statistic for each zone (the mean). ...
1
vote
2answers
89 views

How to calculate raster class metrics by polygon zone?

I have a raster of morphology data where each bin has a code. I want to count the number of each code that fall under a polygon from another file. Zonal stats as table only gives me the min/max ...
1
vote
1answer
333 views

How to use a polygon grid to calculate statistics on line and point features

What seems a simple task but I can't find the right tool to do it. I have a polygon grid cells and say a point feature class. I want to be able to create a table that contains the grid cell ID and for ...