Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

0
votes
0answers
15 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, ...
0
votes
1answer
26 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 ...
1
vote
0answers
21 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. ...
0
votes
0answers
12 views

ArcGIS - Count pixels in two overlapping rasters that have the same value?

I have two raster with five classes each one (each class from 1 to 5 value), they have the same shape and are in the same place, they are in teory "alike", but there are subtle differences between ...
0
votes
2answers
25 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 ...
1
vote
1answer
31 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
1
vote
0answers
24 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 ...
1
vote
1answer
18 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 ...
0
votes
2answers
21 views

Eliminating single raster pixels of flow distance raster in ArcGIS Desktop?

I want to clean up a calculated flow distance raster and need some ideas on how to do it. As you can see in the picture, there are some pixels along streets and rivers (gray) that show connection (...
2
votes
0answers
35 views

Correct resampling method to simulate lower resolution satellite data?

I would like to simulate lower resolution satellite imagery from continuous higher resolution imagery. For example I want to use Landsat derived leaf area index data with a resolution of 30 m and ...
1
vote
1answer
27 views

How to find if a pixel is entirely within another pixel when comparing for example two GeoTIFF raster maps? [closed]

Using GDAL and/or Python Red: GeoTIFF raster Map layer 1 Blue: GeoTIFF raster Map layer 2
1
vote
0answers
28 views

Color different of two Sentinel 2A (L1C) images from the same sensing date

i'm new to this GIS Q&A websites and remote sensing as well, so sorry for this too basic question. It's about my Sentinel 2 (Level-1C) images. I downloaded 2 images with the same sensing date (09-...
0
votes
0answers
69 views

Getting fractional count of pixels in raster map using QGIS?

I have a raster map consisting of 22 land cover classes (LCC). Each pixel is 300 x 300 meters in dimension and contain one of the 22 LCC. I need to make 1 km x 1 km cells in the parent grid and count ...
1
vote
1answer
62 views

Get pixel values from a raster using a multipartpolygon

I'm trying to get the mean value of pixels from an NDVI raster, that intersect the geometry of a FeatureCollection, that is a multipart polygon which represents my sample area, but I can't find the ...
0
votes
1answer
58 views

Extracting pixels in multiple rasters based on the values of another raster's pixels for time series analysis

I'm working with 52 rasters of a specific region over a period of one year in python. I also have a mask raster of the same area that is a binary color (250 black pixels for disparate areas of ...
0
votes
1answer
82 views

Filling no data value in raster using ArcGIS Desktop?

I have a raster with no data values, I want to give them values according to values around them. If a no data pixel is surrounded by 8 pixels whose values are 1 then the no data pixel should adopt ...
1
vote
1answer
81 views

Lost pixels during a raster merge with gdalbuildvrt

I'm trying to merge some rasters with gdalbuildvrt in a python script: rasters = glob.glob('/{0}/ndvi_masked/*.tif'.format(path)) gdal_cmd = 'gdalbuildvrt -q -vrtnodata "0" -overwrite {0}.vrt'....
1
vote
0answers
48 views

Mapping pixel coordinates to lat lon

For a deep learning project, I trained a YOLO based model to detect objects on satellite images (from spacenet dataset; epsg:4326). However, as the Darknet only takes JPG/PNG images as input(to the ...
0
votes
1answer
31 views

Extracting pixels from polygonal geospatial region of set of map tiles and/or set of GeoTIFF files?

I need to create a script, probably JS or Python, to perform the following: I have a polygonal region -- no "holes", and always fully convex -- for which I need to extract the pixel data from one of ...
2
votes
2answers
61 views

How to count pixels in a raster below a given value in PostGIS

The code below works in getting the basic statistics of a clipped raster. I would like to add a metric that is the percent of pixels that are below a given value. I am already calculating the total ...
1
vote
0answers
132 views

QGIS 3.2 - Poor conversion from high-resolution vector to raster

I have a shapefile with polygons with several sizes, and I want to convert it to a raster with 30mx30m pixel resolution. Although I was able to obtain the raster with the pretended resolution (using ...
1
vote
0answers
28 views

Saving Style as SLD in QGIS but after reloading unit changes from map units to pixel?

I have a style I am saving in QGIS (2.18) as an SLD. After reloading the Style onto the layer the ouline width changes to pixels instead of map units. I even checked the .sld in notepad and the uom-...
1
vote
0answers
25 views

Can I change the pixel sizes in a world file?

I start with a dataset that has projection WGS84 and pixel size 0.000274658203125 degrees/pixel. I run gdal_translate to convert it to a PNG: gdal_translate dataset.tif output.png -of PNG -ot byte -...
3
votes
2answers
179 views

Understanding raster units

I have a shapefile with several polygons, and I want to convert it to a raster file with 30mx30m (using QGIS 3.2). I am using "Raster > Conversion > Rasterize", and I am having trouble with the ...
1
vote
0answers
147 views

Extract pixel values at given point dataset and if masked find the nearest pixel value

I need to extract the values at each pixel foe a feature collection from an image and if they are masked the value at nearest pixel, my feature collection is named table and the image collection I am ...
0
votes
0answers
38 views

How to compute a texture value for each pixel?

When computing texture parameters, the value seems to be only on the edges or the four corners of each pixels. The pixel itself does not seem to have a texture value. The pictures below illustrate ...
1
vote
0answers
104 views

Prevent pixel doubling for a mobile display - OpenLayers

I'm programming an OpenLayers (4.6.5) map with a layerswitcher in order to switch between my different layers. On mobile, the display of my layer is blurry, OpenLayers is doubling pixels and I don't ...
1
vote
0answers
83 views

NDVI raster to polygon in QGIS

I have an NDVI raster created through a Parrot sequoia and Pix4D. When imported into QGIS 3.0.2 it is shown as a singleband gray render type with a range of -0.355826 to 0.905562. I want to create ...
0
votes
1answer
151 views

Cloud mask using pixel_qa

I need to create a cloud mask using the pixel_qa band, this is the code that I have so far: var city = ee.Geometry.Point(9.15, 45.18); var landsat8 = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR') // ...
2
votes
0answers
119 views

QGIS change pixel size after multiplication in raster calculator

QGIS change raster size after multiplication in raster calculator: I have layer with size 25x25 pixel as you can see in the picture: When I multiple this layer * 0 in raster calculator (I need clean ...
1
vote
1answer
170 views

Linear regression between every 3×3 pixels between two rasters using R

I have two rasters of precipitation and elevation, PPT and ELEV. They have equal number of rows and columns.I want to create a new raster of precipitation lapse rate (GRADIENT) with same number of ...
2
votes
2answers
129 views

What does Zero pixel value in NDBI mean?

NDBI > 0 indicates built up, while NDVI <0 indicates no built up value. What does NDBI = 0 mean?
1
vote
1answer
110 views

QGIS - Issue with No Data Value Pixel is changing only in header of ascii

I have changed the No Data of a raster Forest.asc into No data = 0 using Raster -> Conversion -> Translate option in QGIS. So, when I add the output raster layer Forest_1.asc in QGIS and check for ...
1
vote
0answers
130 views

Wrong Min and Max Pixel values

I want to convert a raster .tif file into a raster .asc file in QGIS. For this, I am selecting Raster -> Conversion -> Translate option. I am getting the output .asc file. But, both the minimum and ...
1
vote
1answer
130 views

Calculating area of raster pixel when pixels are different sizes at different latitudes using ArcGIS Desktop?

I have a large raster file of total mangrove cover for the whole globe (obtained from NASA: http://sedac.ciesin.columbia.edu/data/set/lulc-global-mangrove-forests-distribution-2000/metadata). I'm ...
0
votes
0answers
104 views

Is there a way to align pixels for different rasters in ArcGIS Desktop?

I have four rasters that are the same cell size in ArcGIS. Ultimately, I hope to use cell statistics to merge them all into a composite. Upon closer inspection, the pixels of the rasters do not ...
1
vote
1answer
489 views

Counting number of pixels using ArcGIS Spatial Analyst?

There is a raster data which contains specific areas separated by layers. My purpose is to count the number of the pixels in those areas. Is it possible to do it in the ArcGIS Desktop 10.5.1 with a ...
1
vote
0answers
83 views

Sieve function in QGIS not working properly? [closed]

I am trying to eliminate single pixels in a (binary) raster with the gdal_sieve function. However, regardless of the settings I choose (I tried threshold=1, 2 and 70 and pixel connection 8), the ...
0
votes
1answer
506 views

how to get every images's pixel values of “ImageCollection” in GEE

I create a Sentinel-2 cloud free mosaic image with Google Earth Engine and exported the image to an Earth Engine asset. I know the image that I exported was composed by several images that taken at ...
1
vote
1answer
155 views

Recovering pixels at intersection of polygon and raster image in PyQGIS?

I am beginner in PyQGIS. I would like to recover the pixels that intersect with my shapefile (polygon) using a loop for ... apparently, the loop is incorrect (no result). Below the code from ...
0
votes
0answers
39 views

Different pixel size between SRTM raster and watershed calculation

I have a problem in GRASS : I am trying to draw a river on STRM 30m. My raster has 30m*30m pixel but when I lauch r.watershed the size of pixel used was much bigger(1km*1km)... An idea?
0
votes
2answers
85 views

Extract areas from DEM between 100 meter contours using r.report or similar tools

I'm trying to extract the total area within the same altitude range in a DEM. As example, I'd like to know the total area between 800-900 m asl of a DEM. Using r.report I've just got this: How can I ...
4
votes
2answers
394 views

AWS Sentinel 2 incorrect cloudy pixel percentage

For some tiles with low data coverage percentage metadata and tileInfo contain cloudy pixel percentage value equal 0. Examples: http://sentinel-s2-l1c.s3-website.eu-central-1.amazonaws.com/#tiles/37/...
1
vote
2answers
2k views

How import many raster in r?

I have different raster layers, but it is not a mosaic. I want to extract all pixel values, mean and standard deviation for each raster. But I prepared my scrip in r, and I import each raster and ...
4
votes
2answers
4k views

Calculate the average of neighbor pixels for raster edge

I have a small raster (or matrix) and I would like to know what is the difference between each pixel and the average of its' 8 neighbors in the case where the kernel window is on the edges and no ...
2
votes
0answers
71 views

Accessing cell value of a wms raster served as ol.layer.Image from OpenLayers

Hi I would like to access the value of the raster cell on clicked location (sort of an indentify tool) of a raster displayed in a webapp as ol.layer.Image via mapserver. I have set the .map file of ...
1
vote
0answers
116 views

Pixel values change after clipping a raster layer

I'm trying to evaluate mean temperatures for the distribution area of European fish species. Therefore, I downloaded the E-OBS data set for mean annual temperature in Europe (0.25 deg. reg., "TG"), ...
0
votes
1answer
1k views

Converting coordinates to pixels with out losing points

I'm trying to convert coordinates from lat/lon into pixel but I lose points in this process. The code that I'm using is the following: from matplotlib import pyplot as plt import numpy as np import ...
2
votes
1answer
427 views

R How to multiply the values of the raster pixels with the true surfaces of these pixels?

I want to multiply the precipitation values (mm) of each pixel of a raster by the area corresponding to each of these pixels under R. At first, I directly multiplied the raster by the average pixel ...
4
votes
2answers
344 views

Is it possible get pixel value with only PyQGIS and not GDAL?

It seems that gdal can caused in some crashes in QGIS, specific in used for raster layers (such as links : QGIS crashes on close if data was read through GDAL in Python Console or GDAL/QGIS broken ...