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

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Tearing of SpatialLinesDataFrame and problem with gClip function

I am trying to use ggmap with geom_map and geom_path commands to add a SpatialPolygonsDataFrame of African countries and a SpatialLinesDataFrame over a raster. When I use the defined function gClip() ...
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30 views

PostGIS update data with ST_Tile

I need to update tiled raster data from the "whole image". I have created this query: UPDATE data_tiled AS t SET raw_data = f.raw_data FROM ( SELECT data_time, data_type, ST_Tile(raw_data, 250, ...
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35 views

raster doesn't redraw to fit the canvas after a zoom in and a pan

i am working with qgis 2.8.2, c++ api and qt 4.8.5 i have a layer in the mapcanvas, this layer contains a raster ( a georef tif picture ) when i zoom in, the raster fill the entire canvas , ok but if ...
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45 views

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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40 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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91 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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54 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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49 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 public....
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45 views

QGIS polygonize tool not working [closed]

I am having a problem using QGIS ver 2.10.1 Pisa. I am trying to use the polygonize function on a raster .tif image, and it runs, but only produces a thin sliver of polygons at the top, then stops ...
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28 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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60 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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22 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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31 views

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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25 views

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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33 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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29 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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1answer
57 views

Performing raster calculations with more than two bands in PostGIS?

We need to perform raster calculations using more than two bands in PostGIS. At the moment, ST_MapAlgebra has a two-band form but doesn't support more than that. I'm open to any solution others ...
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29 views

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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19 views

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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41 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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53 views

Example of C++ code in Visual Studio initializing a created raster

I refer to Sample for MS Visual Studio C++ using GDAL library I noticed that the answer mentions that when GDAL is built from source there would be a tools folder with examples of how to initialize a ...
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19 views

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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2answers
83 views

Vector to raster conversion [solved]

I'm using GRASS but, in case, I'm also familiar with R and QGIS. I'm trying to convert a vector area map into a raster one. My problem is that the resolution of the raster is too low (and I can't ...
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45 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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1answer
18 views

Create image using raster photo layer with vector shapefile overlaid (landuse)

I am a beginner with QGIS. I have a raster aerial photo and wish to overlay a vector shapefile (I have already created) showing polygons of land use. Can this be done in QGIS, or do I need to use ...
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39 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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33 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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1answer
67 views

Clipping raster objects in PostGIS

I'm trying to cutting a raster object (from a PostGIS table) using a shapefile with reference, extracting raster data from a polygon area. My objective to work with the clipping raster into R. I'm ...
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1answer
29 views

Table Select does not work in Model Builder, when using parameter in SQL

I'm trying to create a model that uses values from a single table, in order to perform a different calculation for each raster in a file. Each raster is represented in the table by a row that contains ...
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43 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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66 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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149 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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15 views

IRasterLayerExport3 doesn't save raster until ArcMap closes [closed]

I'm trying to export raster using IRasterLayerExport3, but it saves raster file only after closing ArcMap. It seams that IRasterLayerExport3 creates placeholders for raster (empty file - 3kb), and it ...
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65 views

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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1answer
55 views

Raster processing in ArcPy seems to “simplify”/“round” my resulting values

I'm working off a DEM and doing some raster algebra with it (real simple, add this decimal value, then divide by this value). The DEM in question is super high resolution LiDAR, that's both spatially ...
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2answers
189 views

Creating a raster file from a shapefile using GeoTools with different colours for different features

The shapefiles that I am processing display information on an operation of a piece of equipment over an area, where the information is stored in steps as polygon features with various attributes and ...
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15 views

QGIS world files rather than .xml [duplicate]

Is there a way to get QGIS to write out a world file (.wld/.pgw/.jpw) etc rather than an aux.xml. I see the aux.xml is in general better but it isn't supported by the other software I am using. I can ...
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51 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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1answer
70 views

Problem with importing GeoTif files in QGIS

I have installed the new version of QGIS (2.12) and the newest OSX version (El Capitan). When I tried to open GeoTif files with QGIS, it always crashed! Then I tried an older version of QGIS (2.8) and ...
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57 views

Raster to ascii tool converting all data to one value (ArcMap) [closed]

I am having an issue when converting a raster to ascii. With extract by mask I have selected the area I am interested in and subsequently resampled the data from 5km to 2 by 2 m (required for use in ...
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36 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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28 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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33 views

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 http://i....
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27 views

Best way to store, elaborate and query raster data [closed]

I have created multiple raster images with GRASS-GIS (~150Gb), that I'll need to multiply for a certain coefficient, and query the results that need to by saved just temporally. The portions of the ...
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10 views

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 ...
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46 views

G_Malloc error for Grass module(r.stream.extract) in R

I am having a big issue of this G_malloc Error while using a module of Grass (6.4.4) (r.stream.extract) in R. Initially I thought my computers configuration was low, So I switched to 8gb Ram 64-bit ...
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1answer
49 views

How to interpolate only cells in a raster that are adjacent to existing cells with a value

I have raster data of a continuous field. I need to calculate zonal statistics on that data for some polygons (e.g polygons A and B in the image). It is essential that I have as complete as complete ...
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55 views

Calculating flow distance of pixel from outlet using R?

I have created these raster files for a river basin: DEM Flow Direction Flow Accumulation Also, I have another raster with values of rainfall. All the 4 rasters have same spatial extent, ...
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76 views

can geoserver select one of many rasters from a postgis table

I have a postgis table with many different rasters in it. Is it possible for geoserver to grab only one of the rasters from the table based on something like a where clause?
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148 views

QGIS - Problem in visualizing raster - Raster disappears when pan or zoom

I'm having the following problem in QGIS 2.12.0. When I load a raster, this disappear when I pan or zoom in or out the image. If I try to do some actions three four times, it appears again. It seems ...