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

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How to change null values raster values to 0 in QGIS?

I need help... I'm having problems with QGIS. I have some rasters that appear to have null values, even though I reclassified them to obtain a boolean raster :( How can I change the NULL values to 0?
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Find the intersection of two rasters

I have two raster images, Boolean classified (1 or 2). They overlap in given areas. I need a raster that is only the overlapping sections. Using Arcinfo 10. Answer can only use raster methods, no ...
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Simple Question: Raster from ArcGIS to Geoserver

we have a couple raster files which could be open in ArcGIS. They come with the extension of .aux and .rrd and they are the GRID file format from ESRI. We want to put them on Geoserver to overlay them ...
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How to add Raster legends in QGIS map composer?

Is there a plugin or method to add legends for raster layers (with a custom colourmap) as an item in the print composer?
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Continuous color band for a raster legend in QGIS composer legend

I'm looking for a way to insert continuous colour legend for a raster layer. I managed to create discrete symbols with values along the bar, but I would like to have a continuous bar with some values ...
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How to label raster cells using ArcGIS Desktop or QGIS?

I want to generate a small sample raster (eg. euclidean distance or cost distance) to explain the method of cost-distance analysis, and I'd like to label the pixels with the corresponding cost-value. ...
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Merging hundreds of Aerial Photos into one big file?

I have tried to merge my 405 Aerial Photos into one. I have FME and ArcInfo 10.0 at my disposal on Windows 7 64bit. I have tried the following: create a mosaic; export all images from a ...
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Creating raster or vector raster from DEM point file?

i have a point shape of 75.000 elevation points in a regular 5 m grid. We now want to create a polygon grid with the elevation points as "centroids". Unfortunately, all attempts to do so fail: I ...
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How to resample a batch of rasters using OGR/GDAL?

I'm looking for a function similar to GRASS r.resample. I have a folder full of TIF files and want to reduce their resolution ("scale them down") to reduce file size.
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Setting NoData for a multiband raster?

I have an RGB orthoimage that has black area instead of NoData, as pictured here: When I use the SetNull tool, it does remove the black area, however it then turns it into a grayscale orthoimage, ...
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How to convert raster to point in QGIS

I wanted to convert Raster into Point Vector in QGIS. Is it possible? QGIS have option to convert it into polygon but i didn't found any tool to convert it into point. can anyone help me?
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Raster mosaic not displaying raster values ArcGIS 10

I have eight DEM tiles that I downloaded from the USGS National Elevation Dataset. The individual rasters are displaying correctly, but when I try to combine them in a Raster Mosaic I get arbitrary ...
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Installing 1-band color raster color table?

I would like to use the "1-band raster colour table" extension. I'm using QGIS Wroclaw 1.7.4. In the plugin installer I can't find this extension, even I quote for third party extensions thing. Does ...
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How to clip a vector feature to the extent of an existing raster dataset using arcpy

I have a clipped raster dataset with polylines (from the contour tool) overlayed (see attached). I am trying to clip the polylines to the extent of the raster dataset, which seems simple enough, but ...
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Splitting raster into smaller chunks using GDAL?

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
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How can I convert a DEM into areas of “flatness”, with an arbitrary fill/cut to area ratio?

I want to find areas of relative "flatness" in a DEM. How can I find flat areas? I want to find a neighbourhood of contiguous cells that have an elevation variance that is within a certain ...
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Leaflet rendering TileMill tiles in the wrong order

I'm stumped, and quite a lot of searching has turned up nothing helpful. I'm on the first step of what will ultimately be a map with three raster layers and three layers of markers (with controls to ...
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Extract Raster from Raster using Polygon shapefile in R

I am new to R and using the raster package. I have a problem extracting polygons from an existing raster file. If I use extract(raster, poly_shape) function on the raster it always creates a list ...
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Finding specific pixel values ​​in ArcGIS using Python

I have a raster file containing some integer values. I need to find all pixels whose values are not defined in list like this one: l = [1,2,4,8,16,32,64,128]. Is there any easy way to solve that ...
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Garmin etrex raster maps support

I currently use an excellent set of printed topographic route maps for mountain biking. I would like to scan the maps, georeference them, and upload the maps to a handheld GPS device. Does the etrex ...
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Easily find centre point of a raster in ArcMap 10 document?

If I have, say, a rectangular and georeferenced raster file loaded in an ArcMap 10 document (.tiff w/ associated tfw), how do I easily find its centre point and store that point in a points vector ...
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Creating a raster surface of overlaps from vector polygon shapefiles?

Basically what I'm trying to do (in ArcGIS 10) is to compare three vector files in order to create a 'comparison' raster layer. I tried using Data Comparison (under Data Management tools) but it ...
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QGIS and Raster Mapping in 'Seamless' layer

I would like to use Ordnance Survey base mapping in QGIS. I would like to set up something like a seamless table in MapInfo. I think that the equivalent in QGIS is a Virtual Raster Table. The files ...
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Modify raster layer display and symbology properties programmatically with arcpy or ArcObjects

I have over 1500 NITF files that I need to be able to modify the layer display and symbology of programmatically from within ArcMap. I need to set the properties outlined in red below: I've looked ...
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R - How to sampleRandom() from large raster without NA values

I have a number of vary large rasters which need to be randomly sampled with the return value being a matrix of x, y, and value. The raster package sampleRandom(raster,n, na.rm=TRUE, xy=TRUE) will do ...
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What is the difference between Vector and Raster data models? [duplicate]

From: http://support.esri.com/en/knowledgebase/GISDictionary/term/vector%20data%20model vector data model: [data models] A representation of the world using points, lines, and polygons. Vector ...
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How to extract raster values and create new raster in Qgis?

I want to extract certain values of a raster image in order to create a new raster which then should only contain the extracted/chosen values. How to do this in QGIS?
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Using ArcGIS to filter cells where 7 or 8 of neighbors are different

I have land cover data that I would like to clean using some generalization tools. Majority filter does almost exactly what I want, but is missing one key option. Majority filter allows you to change ...
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NoData values recognised in raster in ArcGIS but not following symbology rules

I have a GeoTIFF raster in ArcGIS, which can be downloaded from the following two links: http://www.rtwilson.com/downloads/MODIS_MOD04_16-06-2006_Subset.tfw ...
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How to animate raster time series using open-source GIS?

I have a bunch of rasters taken about 10 minutes apart, and I have a nice QGIS project that produces pretty enough maps of them. I'm wondering if there's a way to animate this raster series, with a ...
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GRASS - Will r.to.vect work on this scanned map?

Total GRASS noob here. I have several very large hand contoured maps to digitize, and this thread intrigues me. In the past I have spent hours upon hours digitizing these maps and revisions in ArcMap. ...
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How to create points around edge of viewshed results?

Is there a tool or module, or multiple tools, in ArcGIS that will allow you to automate the creation of points around the outer edges of a viewshed? What I am trying to do is gather data about the ...
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ArcMap 10 - Extract raster cells from imagery based on RGB value

I've got some aerial photography (format: IMAGINE Image) which is detailed enough to see to fire hydrants and a shapefile of fire hydrants which was digitized based on some CAD data. My project is to ...
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How can I align two non-coincident equi-resolution raster grids?

I have two rasters: a digital elevation model (DEM) and a Landsat band. The grid resolution of both is 30 m, but the grids are not coincident (see image: the dark raster on top is the DEM; the light ...
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Are there GIS tools for simulating landscape fragmentation?

I am currently looking for any GIS packages (or add-ons) that allow the simulation of landscape fragmentation on raster data. Maybe also other software than GIS tools? Does anyone of you have had ...
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Finding nearest raster cell value based on vector point?

I have two layers in ArcGIS: One is a vector point and the other is a raster layer. I want to append the value of the raster data grid to the vector point. The problem is the vector point is away from ...
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How do I display a raster “Background Value” as hollow for more than one set of RGB values?

I have two overlapping .ecw layers of the same area, though one is clipped in the middle, with a white edge. When I set the background value to 255,255,255, and define it as hollow, it only hollows ...
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Best way to clip a large raster ECW file ?

I am trying to clip a large ECW (details below) but the raster file is too big to be processed entirely. Some details of the ECW below Driver: ECW/ERDAS Compressed Wavelets (SDK 5.0) file size: ...
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Is there an efficient way of sending a large raster image?

Rather simple question: I have two large raster images that are stored in ArcSDE. I need to send these images to someone else, and post it on their ftp site. What is the most efficient way to send ...
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How to sum pixel values within a polygon zone in QGIS?

I have two layers: a raster layer and a vector layer (polygon). I can see the values of the raster pixels but I don't know how to combine them with information from the polygon layer. More ...
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Extract raster by mask output does not completely overlap the mask

I have a flow accumulation grid and a shapefile containing catchment areas. Now I want to do some calculations on them so I need to extract data from cells in the raster adjacent to certain catchment ...
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Finding largest number of observations within a given radius

I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
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In QGIS, how do I remove a band from a raster?

When I process a raster in QGIS it creates a second band. It appears that band has no useful data. I like to use the Raster Colours Tool and it will not accept a raster with anything more than on ...
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QGIS composer - How can I eliminate striping across transparent raster layers?

I have downloaded QGIS dev version 1.7.0-114 and I have come across some weird behaviour in the composer. I create a map with a hillshade and a transparent DEM ontop of it, pretty standard stuff. ...
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How to combine raster and attribute table in QGIS?

I have some rasters representing string categorical variables. Each raster contains integers, used to translate the categorical variables. I have also the .csv tables giving the meanings of the ...
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Simplest way to limit the memory that the raster package uses in R

What's the easiest way to limit the memory the raster package uses in R to 5GB of RAM? Ideally I want any raster that exceeds this size to be written to the hard drive and analysed from a temporary ...
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How to perform enhancement operations on an satellite imagery in QGIS?

I am a new user of QGIS please suggest how to perform image enhancement operations on an satellite imagery like ratioing, contrast stretching, edge engancement, filtering etc. in QGIS?
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How can I change the class of one pixel in a classified image?

I have a classified image (I did it in ERDAS) with six categories. There are some misclassified pixels (especially high-density urban category). Is there any way that I can choose one pixel and then ...
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Loading geotiffs into PostGIS using raster2pgsql

I have an issue with loading some Ordnance Survey raster data into PostGIS. I have been using the following raster2pgsql command to load a tif that I have placed in my C:\Program ...
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Confidence interval from raster data

I have raster data that represents a probability distribution, i.e. each cell has a probability value (in my case the probability that an animal may be found in the cell), and all the cells add up to ...