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

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QGIS georeference raster to world file (WLD)

I am trying to georeference a raster (jpg). I can easily create a geotiff, but when trying to use the QGIS georeferencer to create a wld file instead, something goes wrong. I have the target CRS set, ...
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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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25 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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34 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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63 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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30 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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QGIS 2.14 open raster crash [closed]

I am using QGIS 2.14 on Mac OS X 10.11.3; every time I try to open a raster file, in any format, QGIS crash, any suggestions?
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Is there an 'average' algorithm for st_resample()?

Currently, the docs for ST_Resample() give options for NearestNeighbor (English or American spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. ref: ...
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28 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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44 views

What to do with polygons that were created from a raster file? [closed]

I need some suggestions. I'm working in Arcmap 10.3. I used a NDVI landsat product to find patches of row crops. I then extracted these cells and turned them into shapefiles. I want to measure the ...
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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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Images raster Mozambique

I'm looking for a high resolution raster image for the province of Maputo in Mozambique. I need it to get the elevation and topography for the area of Moamba-RessanoGarcía. Anyone knows any website ...
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53 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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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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23 views

Vector to raster conversion: Gaps within the vector boundary

Is there a tool in ArcGIS that will make the output raster completely encompass the vector boundary? Somewhat similar to select by attributes where all overlapping features however minuscule is added ...
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49 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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transformations from a sphere using R for raster and polygon data [duplicate]

I am planning on using the MODIS burned area products which were produced by Maryland University. These come as either polygons or rasters. In the user guide it says A shapefile version of the MCD45 ...
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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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28 views

Zonal sum gives incorrect results [closed]

I have two raster files: Raster 1 has 7974 grids (coarser resolution) with Rowid, Value and Count. Raster 2 is finer resolution and each grid has values either 1 or 0. What I want to do is to find ...
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28 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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42 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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36 views

Possible to resample tifs in numpy array? [closed]

I need to resample a large number of tif files. Is it possible to put the list of rasters in a numpy array and resample the array? I'm thinking this would be faster than looping through the list, but ...
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40 views

Calculating frequency and area percentage of certain type of landcover in raster data using ArcGIS for Desktop?

I am a rookie in ArcGIS and I am learning raster. My problem is that I have a area of different kinds of landcover(actually it's rock type). Now the road is set to NoData, therefore the whole area is ...
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28 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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31 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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26 views

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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48 views

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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26 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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32 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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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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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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76 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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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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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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42 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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26 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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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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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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23 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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29 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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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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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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39 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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36 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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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 ...