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

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How to unckeck automatically the “No Data Value” predefined on raster background on QGIS 2.14?

I'm trying to import a bunch of rasters, but there is a parameter predefined on the TIFFs, where says that No Data Value should be marked. But I need this unchecked. I opened the metadata, and found ...
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67 views

Why do I get “Insufficient memory for image” although there should be enough RAM?

QGIS reports "Insufficient memory for image 1403x716", when I want to load a raster. The problem begins after 1 hour of work. Had somebody had such problem? System win7 64 bit, 16GB RAM, Intel Core ...
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22 views

Repeatedly losing data sources for raster layers in ArcGIS for Desktop?

I have several raster layers that keep losing their data connection whenever I add a new layer from running a tool. I repaired the data source, but this keeps happening every time I run a tool. Is ...
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17 views

Zonal smoothing on a specified area of a raster?

Is there any way to smooth a specify an area on a raster, such as a DEM, and smooth it? For example, I'd like to smooth out the artifact highlighted in the red box. What is the best course of ...
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75 views

Raster calculator: Insufficient memory available for operation

I use QGIS 2.14 (Windows, 64bit) and try to do some raster calculations with EUNIS habitat data, filter for specific habitat types, files are about 3 GB. RAM: 8 GB (7,85 GB usable) Virtual RAM: 8043 ...
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23 views

Probabilities matrices and cellular automata in IDRISI

I apologize for asking about such elementary things, but I am utterly new to IDRISI yet am now having to learn how to perform certain tasks with it on very short notice. Am I right that, when Markov ...
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22 views

PostGIS: intersection of a MultipolygonZ and a floating point raster

I am trying to isolate the pixels in a floating point raster (loaded in PostGIS) that intersect my MultipolygonZ table (also loaded in PostGIS) and whose values are less than or equal to the z values ...
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61 views

Aligning two raster layers in QGIS?

I am teaching myself GIS in baby steps, I recently acquired aerial imagery (employing RGB and NIR-GB sensors) using a small UAV with the intent of generating a map in a small plot of land. After ...
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26 views

Using color matching on two geotiff rasters datasets and exporting geotiffs

I have one geotiff (tiff + tfw file) that serves as a basemap for a global zone. Then, I have several geotiffs, one for each zone of this big orthophotograph (50 zones in total). I would like to ...
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27 views

Contour Extraction from Scanned Raster Image in Qgis

I have a scanned raster image containing contours and rivers. I am trying to use qgis to extract these contour and river polylines for analysis. As a start I was thinking of the following process ...
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26 views

Do rasters have to be of same extent for the QGIS Raster Calculator?

I am trying to use the Raster Calculator but, I get a raster with Nan values. My rasters are in the same projection system but, one of them, it is a classified landsat map which covers only some part ...
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47 views

How to clip raster to polygons in QGIS

I have two layers. The first one is a vector layer with 6 polygons. The other one is a raster layer. I need to have a specific surfacic information for my polygons (avarage slope value). The ...
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16 views

Raster Imagery Performance

I'm currently building a project that will involve using raster imagery in the field on a Windows tablet with QGIS/Intramaps Roam and haven't been able to get a satisfactory understanding of a few ...
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19 views

Raster and digitized shapefile misplaced in same projection

I have georeferenced .tiff rasters with cadastral borders and corresponding digitized borders in shapefile based on that raster. All that was done in some Mapsoft software. When I insert both in QGIS ...
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48 views

Problem with ST_Union

I have loaded some rasters into Postgis. I did a lot of ST_XXXX (scale, snap to grid,resample) magic to make them aligned. After executing: select r1.rid,r2.rid ...
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60 views

Geographic vs. projected raster cell size area

I am wondering the best way of knowing how to define the area of each raster cell in global data. Specifically, I downloaded all ~400 tiles of MODIS land cover data, mosaiced them into one, and now am ...
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26 views

Flipped (Y-axis) Raster from point cloud

I have been working on a project where I need to create rasters from irregularly spaced point clouds. I am resampling my point clouds to a regular 0.25 cm grid using a nearest neighbor method ...
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38 views

How to correctly rasterize a polygon which crosses 180E longitude?

I want to rasterize a polygon wich crosses 180E lon with gdal_rasterize. The polygon is in the WGS84 projection. I used the following command: gdal_rasterize -burn 1 -of GTiff -ot Byte -ts 1500 ...
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rasterize (R package raster) fail to rasterize island polygons?

I am having problem in rasterezing a polygon shapefile: "island" polygons (I mean polygons which are totally included into a larger one) are ignored and do not appear in the raster. My code is: seg ...
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23 views

Can't display raster in mxd as RGB

I have a script that iterates through a folder of jpgs, clips them to a grid, inserts them to an mxd, and exports them. My original problem was when I added the clipped raster from a standalone script ...
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26 views

How to get a multi-attributes vector from an SRTM raster in QGIS?

I split an SRTM raster into 3 different raster files representing the altitude, the slope and the exposure, using QGIS DEM analysis tools. How can I output a single vector file with the 3 attributes ...
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Raster images in geoserver without WMS

Is there any vailable way to access raster images through geoserver without wms?(to a large number of images)
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How do I change my “no data” values to get “true” values in raster calculator in Qgis

I have two rasters and I want to subtract the values from one of the layers. The first raster is a altitude raster and the second raster is depth values for a lake. I would like to subtract the depth ...
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37 views

how to extract line features from a raster

I have a raster of land cover types where roads are represented by pixels (1 pixel = 25m x 25m = 625 m²). Is there a way to extract line features (here roads) from a raster ? ## Create raster as an ...
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63 views

How to automate the QGIS Raster Interpolation Plugin using python console?

I have a rainfall data from 1961 to 2015 for each day of this years. I need to create a raster for each day with this configuration. Do you know how to automate this using this plugin and python?
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48 views

Spplot SpatialPolygonDataFrame and SpatialGridDataFrame

I have to plot in the same graph something like this: Then, I have elements from SpatialPolygonDataFrame class and others elements from SpatialGridDataFrame class. When I try to plot them in the ...
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29 views

Import raster using raster2pgsql with out-of-db option not working

I am using raster2pgsql to import DTED data into postgis database. I would like the data to be out-of-db, I am using the command as follows. raster2pgsql -R /home/gis/elevation/DTED/area.dt2 ...
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24 views

how to generate a raster with its spatial reference from an array(or matrix) by using pyqgis

I used arcgis to generate rasters from txt files by a certain python api,but i am not familiar with qgis,and now i need generate some rasters from txt files by using pyqgis.The resulting rasters ...
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44 views

How do I create a raster file from a geopandas dataframe storing lats, longs, values, and geometries

From a text file with time, lat, long, and cf values, I create a pandas dataframe (cf_df). Then I use the lat, long values to create a geoseries and create a geopandas dataframe from the original ...
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21 views

Access MEM data from GDAL?

I don't have any answers (yet) from from previous question on GDAL memory raster + OpenLayers, so i'll try to ask an easier question :) Anyone knows how to access GDAL memory with command lines when ...
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How to generalize a raster with noisy edges with ArcGIS Desktop?

I'm trying to generalize a raster to get clean edges (see sample and "optimal" result below). However the borders bleed into each other to a rather high degree. I hacked away at the raster using ...
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Choosing pixel size when projecting raster from geographic to projected coordinate system

I have a raster showing animal abundance in all of Canada. The raster was created unprojected in GRS 80 with a pixel size of 0.0833 decimal degrees. I was ask to project this raster to Canada Albers ...
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28 views

Polygon to Raster tool while keeping less than maximum values

I'm trying to convert a very large, detailed polygon to a raster with a coarser resolution in ArcGIS 10.1 using the polygon to raster tool. The value field is a percentage and the cellsize must be the ...
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27 views

St_intersects returning false results in postgis

I want to intersect point geometry with raster. In postgis I'm executing select st_intersects(geom,rast) from testraster1,pft_pft and the result is false even though the points are sitting on ...
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Same CRS but different units of raster cells in qgis

I have two rasters with the same CRS (WGS 84/UTM 34N). One is from a LiDAR scan and the other raster is created thru interpolation of point measurements by me. I would like to change the cell size to ...
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Kriging results in log mode and SpatialPointsDataFrame manipulation

I've a little problem, probably because I'm not fully expert with R data manipulation. I've perfomed a kriging elaboration of mydata, in log mode, as the classical meuse example, but how can I export ...
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37 views

Extracting data of two overlapping rasters

I am trying extract the data of two overlapping set of rasters (one, a stack of 35 rasters, all from the same source and the second an elevation raster) to get a data.frame of the values (mean of the ...
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Check if raster (part of) lies within a pixel - python/gdal

I have a list of the corner-coordinates of different grid (c1-c4). First i sorted these coordinates to ensure that c1 is the upper left, c2 is the upper right, c3 is the lower left and c4 is the lower ...
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43 views

Turning simple raster file into DEM?

I'm using QGIS LYON 2.12.1, and I want to turn a plain gray scale raster file (that I got from Google search) into a DEM. The aim is to apply the DEM (terrain models) function to the newly created ...
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28 views

How to create a numerical mask file with the elevation points of an area with QGIS

I'm using QGIS and I have to create a mask file (.txt) as an input for a hydrological model. The file should be a numerical grid map that represents the elevation points of a catchment area, like the ...
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32 views

Using arcpy to add several rasters

I need to do some raster/vector processing on some non-overlapping tiles. My python script needs to find the correct tiles and then extract the raster values and count them up. My script needs to be ...
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34 views

Zonal Statistics on discrete values in raster using ArcGIS for Desktop?

I am using ArcGIS 10.3 for Desktop. I am using Corine Land Cover raster data for Southern European Countries, this data gives discrete values to particular land uses (e.g. 1 = agricultural land, 2= ...
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51 views

Why does the flow direction tool in ArcGIS desktop give wrong output (unique values from 1-255)?

I ran the flow direction in ArcGIS, and received unique values ranging from 1-255. I know that these values are wrong, and should be along the lines of 1, 2, 4, 8, 16, etc multiples. The DEM is ...
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114 views

Error in opening Raster dataset in qgis “Cannot open GDAL Dataset”

Error in opening Raster dataset in qgis (see image below). Is there any suggestion as to why this is happening? and how do i correct it?
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Combining Raster and Vector data

I've created a Watershed raster data set (using the Watershed Tool) for a certain area. Within that watershed raster, there are 8 basins that appear I'm trying add the total population to each of ...
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42 views

Handling warning about DX and DY in gdal_translate from .Gtiff to .ASC?

When I try to convert Gtiff to .asc file, QGIS shows the warning: Producing Golden Surfer style file with DX and DY instead of CELL SIZE since the input pixels are non-square. Use the FORCE CELL SIZE ...
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34 views

Attribute table not changing when using Mosaic on rasters

I'm looking to "merge" 2 rasters together. One is the original base land cover raster with 6 classifications/land use classes. The other is a raster from converted polygons that are essentially ...
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27 views

Can't set transparency to a RBG raster on QGIS

I need to display an RGB raster on QGIS, with Multiband Color render type. After I set the Contrast Enhancement option to No enhancement, this is how the image is displayed. No issues so far, since ...
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I clip a raster with a vector mask in qgis, the result is correct but its a little bit of, why is this?

On one side the result is "bleeding" over the vector on the other side its more than one raster pixel from the vector on the inside. How to correct this? http://i.imgur.com/d0v6mqt.png ...
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Adding .tif files with various bit depths to a raster mosaic

So I have a few georeferenced .tif files that I need to add to a raster mosaic, however the problem is that some of these are 8 bit unsigned TIFFs while others are 1 bit unsigned. After adding all ...