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

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Reduce raster resolution and determine pixel inclusion based on % pixel overlap

I'm trying to reduce the resolution of a raster from 1m to 50m using a pixel aggregation (average) method, but I need to set a threshold for inclusion (e.g. 75% of the 1m pixels must fall within the ...
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How does “Mosaic to New Raster” tools works? How does it treat pixel values?

I'm working with arcGIS. I have mosaicked 8 rasters with values ranging from -408 to 180. The new mosaic shows pixel values ranging from 0 to 180.Then I compared cell by cell values from the original ...
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19 views

Map netncf-file with different years and save the different layers in shapefiles

Download from this website the following netncf-file: cru_ts3.23.1991.2000.pet.dat.nc.gz. This is a monthly raster with data from all over the world from january 1991 to december 2000 I am using ...
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31 views

Clipping raster brick object in R

I have MODIS NDVI TIFF files for a year I want to first clip it with a irregular polygon (not by its extent only) of my study area and save it as a multi band raster in TIFF format The TIFF image are ...
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22 views

Adding rasters to mosaic dataset?

I'm working with an ArcSDE geodatabase v 10.0 in SQL Server 2008R2. I added more than a dozen of rasters w/o problem. Server: WIN 2008R2 12GB RAM SPACE: 1TB Created a mosaic dataset (empty) w/o ...
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26 views

Control points in IAdjustXForm for georeferencing of raster (ArcObjects)

I am trying to create a georeferencing tool using ArcObjects in VB.Net. Though only a little text is available on this topic in forums as well as from ESRI; I found an esri article that states the use ...
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19 views

Calculating the distance between points and parts of a underlying raster set

I need your help with a calculation of the distance between points (cities in this case) and forest (raster data). Is there a possibility to collate to every city the distance to the nearest forest ...
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18 views

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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68 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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23 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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18 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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85 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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24 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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25 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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29 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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50 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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62 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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40 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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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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41 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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38 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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64 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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31 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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45 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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30 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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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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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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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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17 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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38 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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30 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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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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52 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 ...