Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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Rasters change pixel size and range of values when imported into QGIS

I have observed that when I import rasters into QGIS their pixel size changes and also, the full range of the raster's value does not appear. For instance, I may have a raster with values ranging from ...
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Error converting a raster to polygons

When I am converting a raster using the polygonize tool, I get this error: ERROR 4: 'C:/Users/Vitor/Desktop/Cartografia EE_Portimo/COS RASTER/cos_raster_reeditada.tif' does not exist in the file ...
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How to calculate interval areas in raster?

I would like to know if is possible and how can i calculate the areas from class intervals in one raster? All help is appreciated, Best regards
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Python Script tools for ArcGIS 10.2 is very slow (get raster properties)

I am using python script tools for ArcGIS 10.2, under Windows 8.1 64bit. When I am using the arcpy.GetRasterProperties_management() command, it's very slow to process the data. For example. I tried ...
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10 views

Raster2pgsql overview method

What is the method used by Raster2pgsql to create overview? I couldn't find details in the docs. Nearest neighbor isn't a very good choice for the dataset I'm working on, but that seem to be the one ...
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Arc - how do I find the coordinates of the centroid of a raster?

How do I find the coordinates of the centre / centroid of a raster? I have tried Zonal Geometry but this does not give me the coordinates. I need to find the centroids of two rasters and create ...
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28 views

Got different cell sizes from a rasterised data

I'm trying to rasterize the Land cover data of Nigeria which was obtained from FAO database. During the process of rasterizing the land cover data, I used the following information which gave ...
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26 views

Overlaying two raster images with no spatial reference

I have two images (X-Ray and Neutron Tomography Scan) of a human bone fragment. I want to use ArcGIS 10.2 to accurately overlay (geo-reference) these two images which have no spatial coordinates. any ...
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10 views

Open and split a 4 channel RGB picture

How can I split an 4 channel rgb pic in qgis? With the value tool I can see 4 channel. I tried to use the RGB to PCT tool but I always get an error (File "C:\PROGRA~1\QGISBR~1\bin\pct2rgb.py", line ...
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24 views

Mapinfo : How to cut a raster with a vector layer?

With mapinfo 12, i would like cut my raster layer .tab with one of my vector layer. How to do this basic task with mapinfo? Is it possible with mapinfo to convert .tab raster table toward any ...
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Transparency on black/white raster after clipping in QGIS?

I'm new to this forum and QGIS. I'ld really appreciate it if you could help me with my problem, since I couldn't find any solution online but people experiencing the same issue. It seems as if this ...
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Mosaic to New Raster not allowing correct overlap

I am not sure what exactly is causing hiccups for me - how I processed the data (removing the white edges in 3rd party software), the bit depth (8bit), the file format (png to support transparency), ...
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Slope tool output has artifacts

So I've tried using the slope tool for a DEM using an appropriate Z-factor and the output is smooth, but it seems to be over-estimating slope angle. I would prefer to reproject the DEM (to NAD 83 UTM ...
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3answers
24 views

Raster algebra to tiled maps on a sever with open source solutions

Let's say I have a collection of data in raster format. It changes daily. Once each day I would like to do some fairly complex raster algebra on these datasets. I would like to be able to do the ...
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28 views

Reprojecting a population raster from LAEA to lonlat

I have a population density raster from the EEA which is based on the CORINE land cover 2000 data. ...
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Raster calculator to create single raster with 4 values from two binary rasters

I have two binary rasters showing habitat suitability (0 = unsuitable, 1 = suitable) under current and future climate scenarios. I am trying to create a raster showing: 0 = cells that are not ...
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44 views

Load the raster image which is in TIF format using QGIS API

I am quite new inthe field of GIS. I am interested in is to load the raster image which is in TIF format using QGIS API I have followed the steps given the in the follwing link to load shape file ...
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23 views

Save rasters created by loop operation to different directory?

I have a set of rasters. I crop them all using FOR loop. Then, I want to save new-created rasters in new directory, not in my actual directory. For one raster it is easy: writeRaster(raster1, ...
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How to get background maps to show in QGIS Cloud mobile version?

we're a group in Denmark, trying to publish some maps for use on a mobile device, but although our background maps show up in the desktop version, we can't get the mobile version to show them - What ...
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Equivalent to Sieve tool in R {raster}?

I would like to remove isolated pixels (or clumps of pixels <9) from my raster image. library(raster) # create some raster data r <- raster(ncols=12, nrows=12) set.seed(0) r[] <- ...
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Isolation and interpretation of vineyard multispectral data

I have 3 band multispectral raster imagery over a vineyard from which i have created a number of indices e.g. NDVI. The data is fairly high resolution (5cm/pixel) so shows a lot of along vine and ...
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28 views

How do you calculate a new field for a raster table based on value from a joined table?

I need to know whether it is possible to calculate a new field for a raster table based on a value from a joined table. Ideally I'd like to be able to accomplish this task without having to add table ...
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28 views

QGIS virtual raster - insufficient permissions

I'm trying to create a virtual raster in QGIS 2.6.1 64b on Windows, but I get the message: "The process failed to start. Either the invoked program is missing, or you may have insufficient ...
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How to remove spikes from grid in SAGA GIS?

I tried to get a grid by interpolating LAS file using Ordinary Kriging. But the product grid has many pixels which values strongly stands out from average surface - I mean one pixel sinks nad spikes. ...
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21 views

Getting raster values on grid nodes

I have my raster layers of Digital Elevation Model, aspect, slope and curvature for a certain region. In this region I want to apply a grid with a certain spacing in its nodes, and then get the ...
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25 views

How to write every raster from a list of rasters?

I have created a list of rasters - "norm" and run a several loops. Now I would like to write every created raster from "norm" (containing 1 layer) into one raster, having its specific name. # I can ...
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How to calculate areas in raster files

I got three files. The first is a shape file for country boundaries and the second and third are two raster files with the global land covers for 2005 and 2009. I'm thus encharged to calculate the ...
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22 views

How to change the raster format using QGIS translate?

I tried to change a raster format from .tiff to .asc using Qgis's 'translate'. As a result, I get 3 files: a PRJ, XML and a file without extension just a plain file... What could it be happening? I ...
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Determine overlap of rasters in different projection systems

I'm trying to improve a python script I have for doing point-by-point comparison between datasets. It uses osgeo. My first input is a netCDF file: I extract the relevant information and store it as a ...
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TIFFDirectory.getAsMetadata() is not including GeoTIFFTagSet. Any solution to this problem? — JAI

The source code appears to simply copy the TagSet List object to the IFD and then the TIFFMetadata. I don't understand where it is losing the tagset as it is in the list before the call. Anyone ...
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24 views

How do I summarize and then normalize the output of a kernel density surface?

I just finished generating a kernel density surface in ArcGIS 10.2. I would like to summarize the raster cell values as a histogram, and then potentially normalize the data. How do I: generate a ...
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42 views

r - increase speed of crop, mask, & extract raster by many polygons

I'm extracting the area and percent cover of different land use types from a raster based on several thousand polygon boundaries. I've found that the extract function works much faster if I iterate ...
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Raster Files Sizes from Point Data Extremely Different

Using ArcGIS 10.1. I created rasters from several groups of point rasters using the Point to Raster tool. All of the points groups are similar size and extents. The first group of points had a file ...
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PostGIS raster maximum number of bands?

Is there a limit on the maximum number of bands you can store in a postgis raster? I cannot find documentation on this. As far as I can remember, a geotiff allows up to the max short integer (so ...
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19 views

Efficiently working with converting vrt rasters to greyscale in QGIS?

I have large raster tile sets working well in QGIS (Ordnance Survey UK data). Sometimes I want to grey/fade these to make my data clearer to see. Attempting to access properties on QGIS for the VRT ...
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Using the accCost() function in R: questions regarding the transition layer

I am trying to use the accCost() function from the gdistance package in R. I load my cost raster using the raster()function from the raster package. According to the documentation, I need first to ...
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51 views

How to import multiple stacked raster images in R?

I have (I suppose) wery easy and silly question but I can´t really find my answer... I would like to import all multiple mosaic rasters (each mosaic is composed by 7 layers) from indicated folder into ...
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How to run GAM with raster package?

When I am using the raster package to predict a surface probability map of species distribution using the following functions in R, the following error occurrs: CA132122200=raster("F:/CBG ...
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Raster symbolization in open source web gis

We would like to build a simple web map application that displays raster data (e.g. a digital surface model) and symbolizes values (e.g. height) using a color ramp. Is it possible to have the user ...
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QGIS Export section from raster to AutoCAD

QGIS Windows 7 I have a raster which displays the flood depth over my site. What i would like to do export to AutoCAD an outline (maybe as a polygon or line) of the sections of the raster which are ...
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Is there an open standard for raster information?

For geographic vector data (Features) there is an OGC standard that defines geometries and their different annotations such as WKT and WKB. For raster image data however, I was not able to find ...
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Color scaling for raster images(batch?)

Let's say I have raster images and I want to change their color based on their data value(color scaling). If the data values are from -(all negative value) - 0, I want to have that colored Blue. If ...
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Calculate Euclidean distance to raster WITHIN multiple polygons

I am using ArcGIS 10.1 on a Windows x64 system. I am working in a study area where I have 360 000 locations of about 50 territorial animals. I have a shapefile containing 125 sometimes overlapping ...
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28 views

Export Geotif with transparent Background

i using Arcmap and i have a raster file, i need export this using a Geotiff file for use in Geoserver like a layer. My problem is, when i export the file always exist a color gray or white in the ...
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50 views

What am I not getting about JPEG 2000 coordinate systems?

I hate to ask this here because I suspect it is a very basic question, but after several days of scouring the web, I need some help with understanding JPEG 2000 imagery and coordinate systems. What ...
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71 views

Whats the best way to convert this tab data to a raster?

I have some grid data that is stored in a xls file. The rows are lattitude and the columns are longitude values in decimal degrees (see image). What would be a quick and efficient way to convert ...
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Error summing 2 different rasters?

I was trying to sum two different rasters and the final outcome is an error (image attached below)? The main goal is to sum the values of each pixel in those rasters (both raster files have the same ...
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29 views

Create raster with distance to feature

I'm new to GIS (and QGIS in particular). I'm trying to create a raster layer that contains the distance to shoreline for a certain region. I have both vector layers of the shoreline (line) and the ...
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38 views

Problems using r.reclass in QGIS: invalid reclass rule error?

I need to reclass some rasters, but i am having a couple of problems, i can´t generate a new raster with the reclassification using the r.reclass of GRASS. For the question here i´m using as example ...
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Calculate raster mode with r.mode - problem with decimals

I am working with a raster file that represents the percentage of vinyards by commune (e.g., municipality) in a region in France. The statistics were calculated for each commune based on surveys from ...