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

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Calculate mean value of polygon from raster in PostGIS

I started with a NetCDF .gri and .grd raster file of the UK provided by a colleague. I clipped it in R to be only London, exported and converted to a ASC file, and then imported it to PostGIS using ...
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47 views

PostGIS - store 2D elevation data

I am new to PostGIS. How can I store 2D elevation data? I have uniform raster and for every [x,y], height is set. I want to be able to use this in my queries (something like SELECT height FROM data ...
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1answer
97 views

Is there a Highest Position tool in QGIS

I am familiar with the tool Highest Position (Spatial Analyst) in Arcgis, but I am trying to replicate this tools function is QGIS. Is anyone aware if this tool exist in QGIS (possibly under a ...
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62 views

How to create contours from an IDW raster

I'm new to QGIS and am trying to create vector contours from this IDW raster. I followed Ujaval Gandhi's "Interpolating Point Data" tutorial step by step but am not getting the same results for step ...
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3answers
45 views

How can I get the UK Land Cover 2007 25m raster data set from Digimap to work in QGIS?

I have downloaded the UK Land Cover 2007 25m raster data set from Digimap (which my university has a subscription to). I have uploaded the data into ArcMap where it works fine, with all 23 classes and ...
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1answer
27 views

Edit raster classification manually using polygons - ArcMap

I want to edit the elevation/z values of certain zones on a raster in ArcMap. I followed this example by creating a polygon, assigning a value of 7.5, then converting the polygon to a raster, finally ...
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1answer
34 views

How to use Orthoengine in PCI Geomatica to georeference Pleiades 1B TIFF to WGS 84

I am trying to use the orthoengine in PCI Geomatica 2015 to reference an image to WGS 84 (ESPG: 4326). Acquisition mode PX Spectral processing PA+XS (resolution is 70cm) I have the associated RPC ...
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38 views

Performing Theil-Sen regression on raster data by R software

I have seven NDVI raster layers (in ERDAS img format) of an area. Each NDVI layer is the peak growing time of that year. I want to do trend analysis of NDVI values change over the years pixel by ...
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1answer
51 views

Overlaying grids with a polygon to determine the average value of the overlapping grids for that polygon

I would like to add the average, minimum and maximum value of, let’s say soil moisture (variable "value" in my case), to each NUTS3 region (= a NUTS3 region is a polygon of a certain small area in ...
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1answer
54 views

How to calculate zonal statistics from multi-band raster for each polygon using python?

I want to calculate the zonal statastics from multi band raster for a polygon layer. When I am using this snippet of code: vectorlayer=qgis.utils.iface.mapCanvas().layer(0) rasterfile = ...
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1answer
81 views

How to get smooth contours from points or IDW raster in QGIS

Hello I'm an artist trying different ways of drawing contours in QGIS using points with income values. I've been able to import a shp file with the data, create a layer with centroids of the census ...
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16 views

Sampling raster by line in QGIS

I am quite new to GIS, and was wondering if you might be able to help me out? I have a raster layer for gradient as well as a line created from GPS tracking points(using the point connector tool). Is ...
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24 views

Spatial segregation from a raster of racial distribution in the USA

I am trying to measure the degree of racial segregation at some geographic level (let's say the county level, for simplicity) in the USA. I have a shapefile with these geographic units. To do so, ...
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1answer
34 views

Importing TIF raster in QGIS, default color band

Where can I change the default color bands for importing raster images? When I import a TIF image the green color band is not set causing a purplish image. When I set it in the properties it views ...
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1answer
55 views

What's going wrong when I reproject raster in EPSG:32115 in QGIS?

I wish to make a QGIS project with an orthoimagery layer and a vector layer of GPS points. I'm using QGIS 2.8.2, 64 bit, in Windows 7 on a Lenova t430 laptop. Raster is in EPSG: 32115 (mercator, ...
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1answer
59 views

Geoserver renders reprojected raster only as transparent images

Trying to reproject WMS layers in geoserver from the default of EPSG:4326 to EPSG:3574 Using the default projection works fine. url = ...
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2answers
30 views

How do you insert values into custom fields when adding to a Mosaic Dataset table?

I have a mosaic dataset (file geodatabase) with an additional field added to it (id that is integer) and I'm trying to accomplish in ArcPy what I can do manually--which is: Add a new raster (single ...
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2answers
55 views

How to sum values of overlapped pixels in thousands of rasters layers and clip it using a polygon in QGIS?

I have a lot of rasters files (more than 6000), each one represents the presence and absence of a species (1 for presence and NoData for absence). The set of rasters covers the whole Latin America ...
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2answers
44 views

Why do my raster pixels not align?

I am working in ArcMap 10.2.2. I am trying to project a NED 3m dataset from a Geographic Coordinate System to a Projected Coordinate System. The output rasters pixels do not overlap the original ...
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32 views

Assigning Raster Cell data to Point data

I have 23 sets of raster data for different types of habitat (which I have performed Block Statistics on in Arc10.2, in order to create a 1km grid). I also have 5 different Sets of point data showing ...
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42 views

How to align hundreds of rasters quickly

I'm hoping to accurately align hundreds of aerial images that are slightly off-kilter. The images cover the same area on different dates (several acres). They contain identifiable features around ...
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2answers
39 views

Converting NoData to 0 values in ArcGIS Desktop?

I have a raster of landcover that I have reclassed and the different land cover classifications are now represented by numbers which correspond to fertilizer inputs. Using ArcGis 10.3, I am trying ...
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38 views

Aggregate / Calculate Cell Statistics >1000 Rasters

I'm looking for a tool/script that does simply what "Cell Statistics - Mean/Sum" in ArcGIS does but for more than 1000 Rasters (TIF) (I need to process ~10000 Raster at once). I'm not used to use ...
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39 views

How to obtain an euclidean distance raster from a vector file in QGIS?

I'm trying to obtain a raster of Euclidean Distances from a vector layer I have of a river in Spain. I did it very easily with ArcMap using Euclidean Distance, but I don't know how to do it in QGIS. ...
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34 views

Where can I download a raster dataset with the latitude and longitude of each pixel in geographic projection?

I want to do raster calculations in QGIS based on the latitude and longitude of each pixel. The calculations will compute the area of the pixel, but also do other calculations for various projections ...
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1answer
41 views

How can i import raster image to GRASS GIS without losing RGB Values?

I am using GrassGIS 6.4.2, How can I import raster data to GrassGIS without losing RGB Values? The raster image format is TIFF, the below commmand is using to import raster image: r.in.gdal ...
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2answers
88 views

Clip Raster to Polygon Grid?

I have a polygon grid file and want to clip my raster imagery to the shapes outlined by it. I am using arcmap and was wondering if there was a tool directly for this? I would like to also be able to ...
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1answer
43 views

Adding pixel value data from a raster layer to a number of buffer polygons ArcGIS

I have created a layer of polygons with buffers around my points of interest, all of the same size, in Arc GIS. I also have a raster layer of nighttime lights with pixel values between 0 and 63 ...
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2answers
79 views

Suitable Raster processing methods to extract field boundaries from images

I'm trying to extract field boundaries and features from a lot of aerial images of agricultural land - and avoid digitizing these features manually. I've managed to get a crude raster file of the ...
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25 views

Invalid drop item: Calculate statistics

I have a number of rasters that I need to calculate histograms for. These are continuous rasters from 0 to 294.208 - many decimal places. I need to be able to classify the histogram down to at least ...
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1answer
46 views

Extracting Data from Raster based on Aspect Raster file

I have 2 rasters, ones shows aspect and another shows date of snow thaw. I want to extract the date of snow melt based on values from the aspect raster. For example I want all the snow thaw dates from ...
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1answer
94 views

Difference between gdalwarp and projectRaster

I am trying to project a Raster. In R there is the projectRaster() function to to this (below a fully reproducibly example) : # example Raster require(raster) r <- raster(xmn=-110, xmx=-90, ...
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34 views

Cannot find information about my.table table in raster_columns

I am running PostgreSQL 9.4 and PostGIS 2.1 and have loaded a small piece USGS SRTM data for North America successfully into my database. I am attempting to export a small piece of of the rasters I ...
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45 views

How should i combine these rasters?

I have two buffers that i want to combine. I tried overlay with fun=function(x,y){return(x*y)} but 0*5 = 0 so it produces NA's.I don't know how to combine them the one buffer should be 500 and the ...
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30 views

Reclass by Table giving output with only 8 catergories

I am attempting to reclass a raster from a table (using the Reclass by Table tool in Arc 10.3). The output value field I am trying to reclassify to is long integer format with values ranging from 0 ...
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17 views

What is the recommended approach to client side clipping, by geometry, of an ArcGISImageServiceLayer?

I have an existing Esri Silverlight application with an ArcGISImageServiceLayer and we need to add the ability to clip that raster, by a geometry. And ideally, do this on the client side since the end ...
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2answers
53 views

Editing .tiff rasters in Python

I am triying to edit .tif rasters in python, but I have some issues regarding the tiff to array converstion. I read there are multiple options for opening rasters (gdal, PIL, matplotlib), but which ...
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2answers
64 views

How to sum pixel values of a floating point raster in ArcMap?

I have a floating point raster with values from 60 up to 95 (with decimals), it has 7077 pixels of 250x250m size. Is there a way to sum all pixel values of this raster? For example, if the raster had ...
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1answer
72 views

How to reclassify a raster in R?

wet<-readOGR(dsn=".",layer="shp") #wetlands r.raster <- raster() extent(r.raster) <- extent(wet) res(r.raster) <- 100 wet.r <- rasterize(wet,r.raster) #rasterize plot(wet.r) ...
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3answers
65 views

Combining rasters to calculate total inputs

I am working on creating a map of total chemical inputs into a study area. I have several raster layers of different inputs with values stored in the attribute tables. I am having a hard time ...
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1answer
80 views

Split raster into tiles

I have a raster that needs to be split into tiles (each tile a new raster). I have a Shape file with multiple polygons (these polygons are how I want the raster split). I have Gdal and QGIS. Any ...
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1answer
39 views

how can I get the majority (dominant) class of a raster to an area (polygon) using qgis?

I have a vector layer with many basic units of planning (zones), a raster layer with three classes of geology and other raster layer of geomorphology with five classes. How can I update the ...
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0answers
38 views

Combining tiff with shapefile

I have a geotiff image with a D_WGS_1984 Datum of land cover for the continental US and I want to be able to merge it with a US counties shapefile. What is the fasters and best way to do this? My ...
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1answer
103 views

How to reproject a raster from lat/lon to UTM in R?

i have to turn it into a UTM in order to make the buffer functional. wets<-readOGR(dsn=".",layer="shapefile") r.raster <- raster() extent(r.raster) <- extent(wets) res(r.raster) <- 100 ...
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54 views

Raster map source for desktop, commercial application

We develop desktop, commercial application for Architects (c++). In a future update, we would like to provide our customers with the option to automatically create a 3D terrain with appropriate ...
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1answer
54 views

How to rasterize a vector dataset in R?

I would like to compare vector vs raster data. So i try to fix a problem using both ways. I made it in vector first : coastline<-readShapeSpatial("shp") wets<-readShapeSpatial("shp") ...
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37 views

Problem with calculating slope in QGIS

Ive downloaded DEM form earthexplorer. But after calculating slope I only have blac img. with same value in min. and max. When calculating aspect or relief, DEM works correctly. Have you met with ...
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21 views

Replacing white or black by alpha channel in raster in QGIS 2.8

I'd like to replace black or white in black and white raster in QGIS 2.8. I perceived that in some other raster where "nan" value automatically occurred and only white or black is being displayed.
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46 views

calculate Z~F from polygon and raster

I have a polygon shapefile and raster layer. How I can calculate the elevation and area (Z~F) relationship for each polygon by using QGIS or ArcMap?
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1answer
228 views

Create raster with grid cells values based on area covered by polygons

I have a polygon data with area covered by the forests (data is here - https://www.dropbox.com/s/zgckliydalljw6a/sp_data.zip?dl=0). I want to convert polygons to raster. The value of each grid cell ...