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.

Filter by
Sorted by
Tagged with
0 votes
1 answer
17 views

How to stack layers (slope, curvature, aspect, etc) derived from DEM to form multi-band images in QGIS?

Made a DEM from Landsat imagery and derived the aspect, slope, curvature, TWI, etc layers (generic flood conditioning factors). I now need to incorporate these layers and feed them to a LSTM neural ...
user avatar
  • 1
1 vote
0 answers
24 views

Pixel-based regression using xarray has incorrect P-value, but everything else is correct

I am using the code from this website to perform a regression on each pixel of an image time-series of rain and NDVI. The code works for everything, that is the outputs match the outputs of scipy, for ...
user avatar
0 votes
0 answers
17 views

QGIS - Avoid DEM cells where no vector contours when using TIN

I'm using QGIS TIN functionality to create a DEM (image attached) from vector contours (image attached). I have set the TIN to Attribute Type = 'Break Lines' and the Interpolation Type = 'Linear'. My ...
user avatar
  • 21
0 votes
0 answers
23 views

How can I change the pixel-size from degrees to meters? [duplicate]

I have a Martian DEM whose pixel size is specified in degrees instead of meters. I was trying to convert in Global Mapper but it didn't work. Now I am trying convert in QGIS with projections but it ...
user avatar
  • 1
0 votes
1 answer
13 views

Getting pixel values from MODIS level 3 product using ArcMap

I wanted to find and map pixels with a certain chl value from the downloaded MODIS Chl data from NASA ocean color web. When using 'identify' tool (ArcMap), I can view the particular pixel value but I ...
user avatar
0 votes
1 answer
53 views

Pixel size convert from degrees to meters of Martian DEM

I have a Martian DEM whose pixel size is specified in degrees instead of meters. I was trying to convert in Global Mapper but it didn't work. Now I am trying convert in QGIS with projections but it ...
user avatar
  • 1
0 votes
0 answers
31 views

How do I generate a grid where each cell is equal to 500 px at 1:250k scale?

I worked this out once but I forgot how I did it. Somehow the grid size created a whole number of cells. I have a map with the following extents: xmin = -20037508.3427892439067364 xmax = 20037508....
user avatar
  • 21
0 votes
0 answers
19 views

Polygon Vertices Pixel are not integers

In a GeoJSON dataset there is the column 'polygon_vertices_pixels'. It says it contains the pixel coordinates of the vertices of the polygon on the matching image. But these values are not integers. ...
user avatar
  • 1
0 votes
0 answers
18 views

How to set image size, resolution and extent for pixel based images comparison

I have to do a comparison between a DEM file and a high resolution image (aerial image) to detect some area in a high resolution image. For this comparison I have to change pixel size, extent and row ...
user avatar
0 votes
1 answer
84 views

How to compute partial correlation of pixels in R

For example, I have 20 years'NDVI and temperature and precipitation rasters. At first,I computed the pearson correlation coefficent with those codes as belows. library(terra) library(Hmisc) ndvi <- ...
user avatar
0 votes
1 answer
59 views

Rasterize a vector layer where pixels just need to include a vector inside, not necessarily on the center

QGIS(3.22) I'm trying to compare a vector layer to a raster layer by rasterizing the layer to the same pixel size as the raster and then using raster calculator. I just want to know which pixels in ...
user avatar
0 votes
1 answer
70 views

Finding maximum value on raster transect between two points using PyQGIS

I have a raster layer and two points with their coordinates, and I want to find the maximum raster value on the line between these two points. Is there a built-in function in PyQGIS to find the pixel ...
user avatar
  • 336
0 votes
0 answers
18 views

how to extract all pixel value from mask area in Google earth engine [duplicate]

Can I extract all pixel values as a list for the masked area (the white area in the figure below) in GEE. I need to know all the pixel values and its indices for the area.
user avatar
1 vote
2 answers
1k views

Extract selected pixel values with their coordinates

My goal is to get the coordinates of all pixels with a specified value (ex: maximum and minimum pixel values). # imports import numpy as np import pandas as pd import geopandas as gpd import rasterio ...
user avatar
  • 151
0 votes
0 answers
22 views

Using extract by mask in ArcGIS Pro about rows and columns

I want to clip a precipitation raster to fit my study area. I have a standard raster of my study area whose rows and columns are 1510 and 1656. However, when I use "extract by mask" tool, ...
user avatar
0 votes
1 answer
97 views

Using Identify in ArcGIS Pro

I am a fresh to GIS. In ArcMap 10.3 I can use the Identify tool to check the same pixel in time series, but in ArcGIS Pro when I load several rasters, it can only identify one layer. What can I do so ...
user avatar
0 votes
1 answer
296 views

Calculate cell/pixel area with Rasterio in Python

The Situation I have a tile spanning 10° north-south (n-s) and 10° east-west (e-w), e.g. from 10-20W and 10-20N. This tile contains multiple pixels, e.g. with a resolution of n-s and e-w of 100m at ...
user avatar
  • 45
1 vote
0 answers
112 views

Is the position coordinate of a pixel the center coordinate of that pixel?

Is the position coordinate of a pixel the center coordinate of that pixel? For example, in an image composed of 4 pixels as shown in the figure below, the coordinate values of 150 and 150 are put in ...
user avatar
  • 447
0 votes
0 answers
46 views

Sentinel2 pixel values and grayscales in QGIS

My goal is to get the Sentinel-2 pixel values and coordinates. So I used python rioxarray_open.rasterio to load the Sentinel2 pixels values and plot the results in QGIS. pixel_value = rioxarray....
user avatar
0 votes
0 answers
54 views

Supervised classification using spectral signature without using any indices like NDVI for crop classification of two classes only

Code: var S2filtered = S2_2A.filterDate('2021-04-1', '2021-04-16') .filterBounds(roi) .sort('CLOUDY_PIXEL_PERCENTAGE') .first(); var S2clipped =...
user avatar
0 votes
0 answers
70 views

Deleting specific pixels in ArcGIS Pro?

I am trying to delete pixels in ArcGIS Pro, but could not get how to achieve it. In the screenshot shared below: The white pixels encircled in orange markers are the ones I want to delete. I did try ...
user avatar
0 votes
0 answers
31 views

Using ArcMap to calculate percent for each pixel

I am using ArcMap. I have a land use file in TIFF format with 10 meter resolution. I would like to know in 30*30 square meter of my file how can I calculate which percent of each pixel of my file is ...
user avatar
  • 9
2 votes
1 answer
99 views

GetMap Request WMS

I formulate a GetFeatureInfo request that returns the feature information of the centre point of the map. The GetFeatureInfo request for WMS is: http://geoservices-inspire.irisnet.be/geoserver/...
user avatar
  • 133
0 votes
1 answer
465 views

Python Gdal: Count pixels having a specific range of values [closed]

I have few hundred raster files and I want to count the number of pixels having values within a specific range. Following code works well when using == operator e.g., raster_file == 25, but gives ...
user avatar
4 votes
2 answers
302 views

Raster color is changed when clipped with a polygon in QGIS

I am using QGIS 3.16.9 and whenever I clip my satellite image bands according to the vector layer I made, it loses its original RGB color. Is there a way to maintain the color/values of the pixels?
user avatar
  • 41
0 votes
0 answers
13 views

Raster pixel size changed after classification QGIS

I've been trying to classify an imagery with k-means clustering for grids tool in QGIS 2.18.22. The imagery is acquired from Sentinel 2-B which should have 10m sized pixel. Before classification, i ...
user avatar
0 votes
0 answers
27 views

Filtering Pixels with same classification in a image collection Google Earth Engine

I had classified with a random forest classifier using a specific training data set composed by random points per each image in a Sentinel-2 imagery. After displaying the results I saw many areas are ...
user avatar
0 votes
0 answers
31 views

Removing background pixels using GDAL in QGIS

I have a raster layer, and its pixel values 255 and 0 are background pixels (outside of the map extent). How can I remove them simply using GDAL? Maybe there is a script for that.
user avatar
  • 1
3 votes
1 answer
153 views

Calculating number of pixels of dominant class in QGIS

I have a land use classification raster file and a grided (5 km² grids) shapefile of my study region. I want to compute a landscape complexity index (LC) which can be computed by: LC = number of ...
user avatar
1 vote
1 answer
69 views

Converting shapefile into raster with desired pixels 1km²

I have one shapefile and I want to convert into 1km by 1km pixels in QGIS. Because my raster image is of same resolution so I want to merge and see how many houses are in one cell. I rasterize my tiff ...
user avatar
  • 318
0 votes
1 answer
37 views

Raster math with latitude-specific correction factor for each pixel

I'm working on a problem that requires creating a new raster from a large (~100 GB) global basemap. A different correction factor must be applied for every degree latitude of the basemap, making an ...
user avatar
  • 11
0 votes
0 answers
85 views

Getting the pixel value from the user defined Image (which converted form a FeatureCollection)

There is a simple FeatureCollection, and the reduceToImage() function can convert this FC to a google-earth-engine image. How can I get the pixel value from this image. This is the JS code: https://...
user avatar
0 votes
0 answers
86 views

Changing raster pixel values outside of polygon box using rioxarray

How do I change all raster pixel values outside of a polygon (keep the original values inside polygon) into a certain value? I have passed through rioxarray clip() like below from this link: ...
user avatar
  • 57
4 votes
3 answers
577 views

Calculating the number of points per raster pixel

I'm working with QGIS 3.14.16, where I have a large dataset of points (in a shapefile) and a raster of my study area. I want to calculate a new raster with the number of points in each cell. I've done ...
user avatar
  • 119
2 votes
1 answer
118 views

gdalinfo on partial GeoTIFF file

I'm trying to determine the pixel size and corner coordinates of a GeoTIFF file in a cloud service that I'm developing, before uploading the file completely. So my plan is to upload the first 10kB or ...
user avatar
2 votes
1 answer
43 views

Scaling a soil profile Raster to georeference and vectorize Raster data

I have pictures of root patterns, where each root is marked by a point. We worked on soil profile walls, so there is no coordinate system to use as a basemap. I loaded it to QGIS and classified it ...
user avatar
  • 55
0 votes
0 answers
527 views

Calculating area or counting number of pixels by category using Python

I am trying to count the number of pixels and calculate the area of each category in 5 images. The categories are 1,2,or 3 in three of the images and UP and P in two of the images. How do you ...
user avatar
  • 47
0 votes
1 answer
78 views

Count the number of water pixels in an image collection (Landsat 5)

I'm trying to count the number of water pixels across a Landsat 5 image collection. I have a script which I believe is successful in identifying the water pixels in each image and spiting a chart with ...
user avatar
  • 3
7 votes
3 answers
319 views

Shifting existing points (Shapefile) to the center of raster pixels

I have some points in a shapefile in order to sample reflection values out of raster files. As these points are not positioned exactly in the center of their respective pixels, I am looking for a tool ...
user avatar
  • 447
1 vote
0 answers
60 views

Transform pixel-coordinates from input image to pixel coordinates in output image

How can I transform pixel-coordinates from input image to pixel coordinates in georeferenced output image? I want to georeference images (frames of a video) with GDAL and GCPs. But besides the ...
user avatar
  • 11
0 votes
0 answers
87 views

Problem with pixel values of monthly composites of Landsat 8 when downloading from GEE to Google Drive

I am trying to download Landsat 8 monthly bands using Google Earth Engine. While on GEE the pixel values are correct. When I download the images on my PC I'm getting a range from -1,7e+308 to +1,7e+...
user avatar
  • 190
1 vote
1 answer
112 views

Creating raster with specific value cells of certain size in QGIS

I have created a raster containing cells with 2 values (1 for content > 0.65 and 0 for all other values). One cell is 25x25 m. I ran r.neighbor to find out which cells are in the neighborhood of ...
user avatar
  • 85
1 vote
1 answer
84 views

Measure between two images in QGIS 3.18

I'm currently working on QGIS 3.18 in the area of geo-referencing. I have two orthophotos (they are same) but the first one is untreated, the second was corrected by differential GPS. I want to ...
user avatar
  • 39
0 votes
0 answers
34 views

Strangely scaled and pixelated font and buttons

I'm completely new to the world of QGIS and GIS in general. I'm going through the official training manual, and I'm having fun and everything is working out all right. For some reason, when I got back ...
user avatar
0 votes
0 answers
26 views

Adjusting pixel values to new pixel sum

I'm working with land use rasters in QGIS. For my application I have created rasters with pixels that have a fraction of 0-1 (for 0-100%) for a land use class. So for example in my settlement raster ...
user avatar
3 votes
1 answer
774 views

Changing pixel's dimension (raster) on QGIS

I would like to change the size of the pixels from 2.5 to 10. How can I achieve this?
user avatar
  • 177
3 votes
2 answers
126 views

Visually differentiating raster pixels in area of same value QGIS

Given a discrete band, and say an area that for example all has the value 5, is there a way in which I can highlight or differentiate where pixels start and stop? This doesn't have to be some ...
user avatar
  • 35
0 votes
0 answers
64 views

GDAL changes pixel resolution when transforming from HDF to netCDF

Using the MODIS product MCD18A1.061 (DSR 1km), tile h15v05-2001001, my goal is to extract the scientific datasets that are contained in an HDF to several netCDFs. For this, I used the following gdal ...
user avatar
1 vote
1 answer
53 views

Set all raster values from decimals to integers on OQGIS

I have a raster map made up of numerous pixels with decimal values. Is it possible to change these values from decimals to integers?
user avatar
  • 177
3 votes
1 answer
143 views

Setting pixel value from 0 to 10

How can I change the pixel value from 0 to 10 on QGIS?
user avatar
  • 177

1
2 3 4 5