Questions tagged [pixel]

In digital imaging, a pixel, or pel (picture element), is a single point in a raster image, or the smallest addressable screen element in a display device. In GIS applications, a pixel may also refer to an imagery layer or other raster data.

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14 views

Rotating pixels in dataframe? [closed]

I have two absolutely different raster dataframe. I must merge them, but the direction of the pixels are not same. How can I solve this?
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17 views

Cannot get number of max pixels in Google Earth Engine

I have a code that calculates the max number of pixels among all the rasters it retrieves and then creates new imagecollection with only rasters that contains rasters in the size I want. For some ...
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1answer
22 views

GDAL Sentinel-1 pixel size

We know that fields related to "Geotransformation" and "projection" are empty when one tries to access these information using gdal on Sentinel-1 (at least the GRD products). I normaly use: gdal....
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22 views

Pixel resolution units

I am working with Sentinel-1 images. at this time I am focusing on S1-GRD products. Based on the Sentinel-1 dodumentation we know that GRE images are the same SLC images which have gone through ...
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43 views

Scatter matrix using pandas does not reset any graph

I would like to find the statistical correlation between all the pixels of an image in relation to the bands. In my case 7. from osgeo import gdal from osgeo import gdal_array import numpy as np ...
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1answer
36 views

Rounding to nearest multiple of pixel resolution using ArcPy

ArcPy can return the pixel resolution: arcpy.GetRasterProperties_management(rasterfile, "CELLSIZEX", "").getOutput(0)) Let's say this returns "3.2808" I wish to be able to take a given input, say "...
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1answer
27 views

Why does Earth Engine report Sentinel-2 pixel depth as 16-bit when it is 12-bit?

When accessing Sentinel-2 through Earth Engine search bar, the info page that pops up reports the bands as UINT16 when in reality they are 12-bit. Am I interpreting this incorrectly?
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38 views

Count the number of pixels according to their value using for loop

I have script that does the enxt procedures: create imagecollection from Landsat7 clip the images according to specific geometry and calculte NDVI for each one filter the rasters according to the ...
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1answer
69 views

Count number of pixels [closed]

I have two layers: polygon and raster. Could you tell me how to count the number of pixels which intersect with polygon layer? Raster is too large to creating fishnet or convert to vector (time ...
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1answer
43 views

Extract maximum pixel value vertex from a raster for a given grid cell without altering the position of the source location in QGIS

I have a 0.5 X 0.5 metre resolution raster. I would like to extract the maximum value points from the raster for every 2 metre square cell. And the extracted points should be in the centre of the ...
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3answers
35 views

Extracting pixel values in different bands for different points giving NAs and not pixel values

I am working with R statistics. And I am trying to extract pixel values for each point in each Landsat bands, however, I am just getting NAs instead of getting pixel values Does anyone have any ...
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Reprojection problem with Rasterio

I have already processed so far NDSI map by using Rrasterio, NumPy, os and matplotlib.pyplot for plotting the data. Now, I would like to eliminate permanent ice from NDSI map. I am facing one major ...
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88 views

QGIS convert pixel location

Is it possible to convert a list of pixel locations (txt file) into lat long? What I have is: (left_x: 137 top_y: 146) (left_x: 175 top_y: 236) (left_x: 182 top_y: 153) (left_x: 185 ...
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26 views

Simultaneous raster downsampling/downscaling and upsampling/upscaling for false accuracy minimisation

I want to have a raster stack of two different resolutions. One is from VSNIR and one from SWIR sensors (hyperspectral). The VSNIR has a resolution of 25 cm and the SWIR of 80 cm and both data have ...
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31 views

Convert pixels to coordinates

I have a vertical image with size (W,H). I have info about the coordinates in decimals of the the upper left and bottom right (Lat1,Lng1,Lat2,Lng2). I have the Ground Sample Distance (GSD) of the ...
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45 views

How to calculate mean pixels value of shapefile (for specific place)?

I have GeoTIFF image. I want to know how to calculate specific area mean pixels values? Is field calculator for(value*count fields) right or get raster properties? Or what can I do?
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13 views

No Data Value through Pixel Inspector in ArcMap

I have a raster that represents temperature on a global scale derived from satellite data. Initially it had pixels in the ocean assigned -9999. After I used SetNull tool to eliminate them they show up ...
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2answers
65 views

Get geographic coordinates based on pixel coordinates?

I'm working with Mask R-CNN to locate fires. I have the following image. I have info about the geographic center coordinates of the image, and the orientation of the image in degrees let's suppose ...
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24 views

OpenLayers3 map.forEachLayerAtPixel bug

Hi I'm working with OpenLayers version 3 and using method map.forEachLayerAtPixel(). The problem is I usually work on big screen and now I have switched to my laptop with smaller one and suddenly ...
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2answers
50 views

Selecting all the pixels in a raster coverage that have a specific pixel value? (in PostGIS raster)

I have a land use map in the format of TIFF. I imported this file as a table in PostGIS using raster2pgsql. The land use file has 7 different classes. How can I select all those pixels that have the ...
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1answer
38 views

Extracting pixel values for specific point locations in WGS 1984 / EPSG: 4326 image

I have a remote sensing image with GCS WGS 1984 / EPSG: 4326. I need to extract pixel values from this image which corresponds to specific point locations. For that purpose, I defined these ...
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1answer
239 views

Getting coordinates of pixel from georeferenced drone photo?

I have a problem with geo-referenced photos from a DJI drone. I have the coordinates of the center of the photo and the metadata related to the photo and I would like to know how to go from a pixel to ...
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1answer
75 views

Raster calculator - problems with syntax

I have a raster layer with values ranging from 0.00597303 to 0.102894 and I want to assign specific number representing a group to specific range of values: Group 4: x >= 0.1 Group 3: 0.01 <= x ...
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47 views

Updating raster pixel values where they overlap with another raster band

I am trying to replace/update the raster pixel values of band '3' of a Land Cover Map to a new value of '24', but only where these pixels overlap with value '4' of another raster layer. How do I write ...
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25 views

Getting stripe across tiles without buffering image?

I am new to geotools. I need to get a horizontal stripe of bytes from the image data without buffering the whole image. I've looked at the various envelopes and pretty sure I could use just ...
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1answer
133 views

Calculating the distance of each pixel in a raster from a point in PostGIS [closed]

I have a raster in PostGIS and a table of points. I want to calculate the distance of each pixel to each point. How can I do that? For example, if 9 pixels and 3 points, then I want to calculate 27 ...
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1answer
111 views

How to write a single pixel or a line of pixels to GeoTIFF using GDAL/Python

Let's say I want to write a single pixel or a 1D array of pixels (e.g.all at the same latitude) of pixels to a single-band of a Float32 GeoTIFF using the Python GDAL bindings. How can I do so? Or is ...
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2answers
63 views

Cannot read pixel value from DTM raster with QGIS

I am using this DTM: http://ags.cuzk.cz/arcgis2/services/dmr4g/ImageServer/WMSServer?request=GetCapabilities&service=WMS At ArcGIS I am able to ready pixel value of the raster but at QGIS it ...
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37 views

delete pixels intersecting vector border

I have a two files : vector file : polygon (red) raster file : got by clipping a raster file using this vector file (Green) I want to delete pixels that intersect with the vector border (I want to ...
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1answer
71 views

Wrong masked pixels

I am new in GEE, and tried to run a simple code to mask cloud pixels. However when I added the image selected with my filters I saw that the result of the cloud filter are empty areas, as shown below: ...
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1answer
58 views

Explanation of reduce.count() function in Google Earth Engine

Following the indication on Calculating number of pixels in polygon using Google Earthy Engine? I wrote this script: var gfc =ee.Image('UMD/hansen/global_forest_change_2018_v1_6'); var lossyear = ...
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Is there a way to interpolate lost data/lost pixels caused by cloud and cloud shadow masks in Google Earth Engine? [duplicate]

I'm sure cloud and cloud shadows have been, time and time again, a frustrating problem. Usually after masking the two, I composite multiple images (in a set time interval e.g. 2015-2016, months 6-8) ...
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48 views

Obtaining pixels between 2 raster layers (border)?

I have a rasterStack obtained from a stack of 3 raster layers by: image = stack(A, B, C) I would like to calculate the distance between the pixels of layer A and pixels of layer C. After ...
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241 views

Calculating pixels coordinates from lat/lon

I'm trying to develop a WPS that would print maps to images and PDFs. I don't want to use Mapfish because of its limitations, and because of some customization I need to add to the printed maps. My ...
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1answer
454 views

Calculating distance between point and selected pixel in R?

I would like to obtain the distance between a point and a selection of pixel on raster image. Here the process: I read my JPEG image and extract colors I want: img.raster<-stack(***) names(img....
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1answer
53 views

Calculating distance between each pixel of rasterstack image?

I am new on R and I have an image of class "rasterstack" of only 3 colors: Red, Green and blue as illustrated: I use this function: image = stack(img.red, img.green, img.blue) I would like to find ...
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1answer
55 views

Using GDAL Warp results in odd pixel sizes and gaps

I am mosaicking one meter and three meter rasters to two meters in Python with GDAL Warp using the following code: cl_string = "-of GTiff -co COMPRESS=LZW -tr 2 2 -tap -r near -overwrite \ -multi -wo ...
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3answers
169 views

Converting raster pixels to vector cells?

Is there any way to convert raster pixels to vector cells? I mean each pixel to a polygon. I tried the SAGA tool 'Raster values to points' by choosing cells option instead of nodes option. As a ...
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1answer
288 views

How big is a MODIS 250m pixel in reality?

How big is a MODIS 250m pixel in reality? This appears to be a question that contains its own answer, but I have several reasons to doubt that the pixel size is actually 250m x 250m: I downloaded ...
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1answer
68 views

Creating raster with custom values? [closed]

I have a problem: I need to create a raster with all pixels values = 0, but one of these pixels must have the value = 1. This pixel has especific XY coordinates related to an in situ station. I need ...
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2answers
236 views

Calculate 16-bit elevation values from a 32-bit RGBA image?

Say a single-band 16-bit (UInt) raster with values representing elevation (meters) must be converted to a 32-bit RGBA PNG image (8-bits/band) for use in a web application. The image dimensions must be ...
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1answer
58 views

Obtain pixel coordinates of an image

I'm working with a tiff image in arcgis projected in UTM 33N and I need to obtain pixel coordinates of a specific point in the image with known metric coords (UTM 33N). How can I get them?
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61 views

Rotating orthophoto based on polygon boundary (rotated pixel)?

When I clip an orthophoto using a vector polygon, the resulting pixels orientation is north-up like as shown in the graphic below. I used Global Mapper, ERDAS, Arcmap "Clip" "Extract by Mask", "...
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1answer
40 views

Does the MODIStsp package computes the QA's and eventually corrects the bad quality pixels?

I am using R's MODIStsp package for downloading MOD11A2 time series products. While executing the command it was written that QA's were computed. Several files were created, LST_Day_1km, QC_Day, ...
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197 views

Using raster stack function time in R?

I successfully ran a function over a smaller test raster stack (48 layers) in about 30 minutes but cannot run it over my large stack (1462 layers). The last one I tried over the large stack ran from ...
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150 views

Clean up pixel noise from raster in ArcGIS

I have this raster. It has some pixels near the main objects, this raster is a product of a classification. those little pixels have the same value of other big objects, so I cannot just reclassify. ...
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2answers
604 views

Getting all pixel values from raster image in ArcGIS Desktop?

I am using a CHIRPS raster image on ArcGIS 10.6 and there is no attribute table, I need the pixel values as it is the individual rainfall data for the stations to perform further statistics on. How ...
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1answer
99 views

Pixel count on AFR Raster in ArcGIS?

I have this kind of raster which has no pixel count in his attribute table. I'd like to calculate the pixel count by class: These are the raster's properties
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51 views

How to get the area of the pixels of a raster in Africa Lambert Conformal Conic CRS in R

My question has been previously asked here (R How to multiply the values of the raster pixels with the true surfaces of these pixels?), I have to multiply the precipitation value of each cell by the ...
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1answer
59 views

Converting proximity from PIXEL distance to GEOmetric distance in QGIS

I used the Raster>Analysis>"Proximity (Raster distance)" tool in QGIS in order to create a raster of distances to a particular value in another raster. This is the same sort of thing someone might do ...