Questions tagged [raster]
Raster is a data format consisting of regular grids of values, usually stored in an image-like format.
2
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0answers
40 views
How to resize a raster to the same extents of an equivalent raster?
So here's the problem
I have a georeferenced orthomosaic which I used to generate land cover data.
During the pixel classification phase of land cover study, I had to use other softwares to help me ...
-2
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0answers
15 views
Pixel-Level NDVI : what is it
I have basic knowledge on how to compute floating or integer based NDVI value of an AOI on daily, weekly, monthly or yearly scenes BUT do not understand what is meant by pixel-level NDVI value. ...
3
votes
1answer
42 views
Root Mean Square Error of 2 raster layer in QGIS
Is there a method to calculate the RMSE between 2 raster layers in QGIS?
I have 2 point cloud files, 1 edited and the other not. After triangulation of each layer I have obtained 2 raster files.
I ...
2
votes
0answers
25 views
Maintain raster color rendering across arcgis and qgis
I have a 16-bit satellite geotif. These images can be visualised in a number of ways, depending on which stretch you apply.
The default stretch applied by ArcGIS to these images produces a "natural" ...
0
votes
1answer
19 views
Retaining bands when pansharpening
I am currently pan-sharpening 8-band multispectral raster satellite images with single band panochromatic images.
I use Arcmap pansharpen raster function to achieve this.
The pansharpened result ...
2
votes
1answer
46 views
Translating vector by raster DEM data in QGIS?
I'm trying to follow the set of instructions here: https://twitter.com/imhere_asia/status/1023055838787690496
[EDIT]
Pasting the instructions here for reference so people can avoid twitter.
...
1
vote
1answer
17 views
r raster: unique returns duplicated values?
I am using function unique() in package raster. I expect it to return the unique values for each layer, yet I get duplicated values... is that the expected result, or is there an issue somewhere?
...
2
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0answers
18 views
Projecting a PRISM raster from NAD1983 to Albers Equal Area PCS in ArcMap: Why does my raster change position and cell size?
I want to perform zonal statistics on PRISM precipitation rasters using watershed shapefiles as my input zone features. I'm operating under the precept that I should project all my data into the same ...
0
votes
1answer
13 views
Subset raster stack with logical indeces R
Is it possible to subset a raster stack by indexing on a logical vector?
r1 <- raster(nrow = 100, ncol = 100)
r1[] <- round(runif(ncell(r1), 1, 4), 0)
r2 <- raster(nrow = 100, ncol = 100)
r2[...
3
votes
1answer
45 views
Watershed a catalog RasterStack in place of RasterLayer in lidR?
I want to use watershed with lidR package on a catalog. I paste this command:
rep <- "/home/lasfiles"
new_ctg <- catalog(rep)
lidR:::catalog_laxindex(new_ctg)
opt_output_files(new_ctg) <- ...
0
votes
0answers
16 views
Adding raster values to polyline using ArcGIS Desktop? [closed]
Looking for a way to add raster attributes to the length of the polyline which overlays it. Union sounds like a good option, however it does not accept raster format. Any other suggestions?
Using ...
0
votes
1answer
19 views
Converting Raster Density File into Point using ArcGIS Desktop?
I used the Point Density tool to create raster files. I plan on scaling these density values by dividing them by the greatest density value and then multiplying the result with a certain value that is ...
1
vote
0answers
29 views
Extracting shapely polygons from .png file? [closed]
I have a .png file coming from a WMS service (WFS is not available). It only contains "straight" lines and I would like to extract the geometries (shapely polygons) of the connected components of ...
2
votes
1answer
24 views
Raster Palet remove categories/colours
I'm rather new to QGIS and I have the following issue:
I have a raster image with 255 different categories all having their own colour. However, I want to cut out some of this data as it is not ...
1
vote
0answers
24 views
Translating raster to ZMAP Plus Grid?
I have been converting data published in is ESRI’s public ASCIIgrid format to ZMap Plus Grid in QGIS 2.18.6 .
When I tried to continue on my work, I suddenly received the following Error message:...
0
votes
1answer
21 views
QGIS 2D Raster Area Calculation
I have a set of point cloud data in QGIS. After triangulating them and forming a Raster temporary file, i would like to find the 2D surface area of this file. IS there any tool to do it? Or do i need ...
-3
votes
1answer
73 views
What is the problem?
After running raster>conversion>polygonize (raster to vector)I was given the following message in qgis 3.4.4. What should I do?
Processing algorithm…
Algorithm 'Polygonize (raster to vector)' ...
0
votes
0answers
23 views
Empty output rasters when running the bfmSpatial function in R
I have 131 monthly MOD11A2 (LST) images and I want to make a time series analysis using the BFAST Monitor. The images came from the average of the original 8day products. I have made them a time ...
1
vote
0answers
23 views
gdalwarp looses pixel information
I have an ungeoreferenced .tif of which I know the spatial information. However, when I run the following command it looses all unique values. All pixels have the value 32, which is the upperleft ...
0
votes
0answers
8 views
Change raster symbology in Google Earth
I have a raster with discrete terrain classes that I want to visualize in Google Earth (Pro). However, when I import the .tif, Google Earth gives it a black-white stretched symbology, as opposed to ...
1
vote
2answers
60 views
Turning degrees into square kilometres (km2)?
After running raster layer unique value report I have got pixel number and area in degree.
How can I turn it in square kilometres (km2)?
-2
votes
0answers
31 views
Comparing raster and vector data models? [closed]
I found some GIS literature about comparing vector and raster models ("vector vs. raster ") sometimes in tabular or a list form. For example:
Source 1: https://www.ordnancesurvey.co.uk/support/...
-1
votes
0answers
16 views
Split raster into 4 equal tiles with splitRaster() function in R, error [closed]
I want to split multiple raster into 4 equal segments, I found the splitRaster() function from the SpaDES package, which seems to do exactly this. However, it results in an error while executing.
...
1
vote
0answers
23 views
Warning message in raster::rotate(): “this does not look like an appropriate object for this function”
I'm attempting to rotate a stacked raster using the raster package in R. The raw stacked raster looks like this:
When I attempt to rotate the raster to change the longitudinal scale from 0-360 to -...
1
vote
1answer
19 views
How to import coincide table of r.coin tool of QGIS in Excel
I am trying to do a crosstabulation analysis with QGIS. I have used the grass tool r.coin and I have got the coincide report in txt format. However, I want to work with that report in excel, but I don´...
1
vote
0answers
32 views
Importing Raster to PostGIS?
I am new to PostGIS - on windows 10. I have managed to install it and have a database with vector data working in QGIS.
I am now trying load raster data. I have edited the PATH to point to Postgres ...
0
votes
0answers
19 views
DN / Temperature conversion (Zenmuse XT) [closed]
I acquired thermal images with a zenmuse XT.
I would like to import these images into qgis to perform raster analyzes.
However I can not recover the right formula for converting pixels into ...
1
vote
2answers
51 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 ...
1
vote
2answers
50 views
How to make a raster gradient in any direction in R
How can I create a raster, where the values increase in a certain direction?
I know how to do the "main" directions with full 90 degree steps, as illustrated in the image. But I would need some help ...
0
votes
1answer
16 views
Unable to load file using gdal.Open
I am new to GDAL in Python (and Python in general), so as a way to begin learning, I am trying to perform basic functions such as getting extents from a single raster and printing them out.
However, ...
2
votes
1answer
33 views
QGIS raster rule-based coloring
I have a raster with different values (negative and positive). I want to color the raster based on a rule: All positive values have a certain color and all negative another. I don't want to use '...
0
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0answers
23 views
Removing black border of raster TIFF georeferenced image using ArcMap?
I had read other questions but there is no transparency panel in my ArcMap
1
vote
1answer
31 views
How do I turn a fog belt zone raster map into a geographic map of expected fog?
I'd like to make a map that shows the amount of fog by San Francisco neighborhood.
I'm using QGIS. I have some of the pieces:
a geoJSON file for each of the neighborhoods.
a raster map with a ...
1
vote
0answers
31 views
Orthorectification with R
How can I orthorectify an oblique image of a flat landscape when I know the conditions of the photo (coords, height, direction, lens, etc)?
I would like to perform this kind of stuff from GRASS ...
0
votes
3answers
48 views
Deleting portion of raster using ArcMap?
How do I delete a portion of a raster image using ArcMap?
Attaching the raster image and the portion to delete.
3
votes
2answers
39 views
Create a bounding box from point shapefile
I have a BigTiff image and an associate point shapefile with features. I would like to know how can I create a bounding box from that shapefile to create/clip images around that points to train a ...
3
votes
2answers
77 views
How do I calculate the Terrain Ruggedness Index for each county in the United States in R?
I have a shapefile of US counties and high-resolution elevation data that spans the entire contiguous United States. My goal is to calculate a terrain ruggedness index for each county. The functions (...
0
votes
0answers
31 views
Running Linear Regression with multiple Rasters converted to a numpy array in Python
What I did was an array with Rasters from 2000 to 2018. It's temporal Resolution is 16 days. I more or less wrote my code by combining scripts that I found matching my problem. This is what I got so ...
1
vote
1answer
40 views
Units of specific CRS projection?
I use a shapefile with CRS
("+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0").
I want to calculate a buffer around the points with 'extract' from raster package. How can I know the ...
1
vote
0answers
26 views
How to write raster in saga format with python
I try to write a raster file in SAGA GIS format (sgrd). My script is work but some information is missing in the final file (i.e output.sgrd).
Here is script :
from osgeo import gdal, ogr, osr
import ...
0
votes
1answer
21 views
Setting pixels of a all raster layers in a raster stack to NA based on the pixel values of corresponding raster layers of another raster stack
I have MODIS NDVI product (MOD13A2) for 10 years in HDF file format. Here i have 230 of such HDFs. For a single HDF, I want to set NDVI pixel values to NA with respect to Quality values in another ...
0
votes
0answers
21 views
Project data into WGS from rotated raster (CMIP5 file ) in R
I have this raster (less than 10 mb). It is a historical simulation model (SMHI) created by CMIP5 clipped for the city of Amsterdam.
dropbox <- here is the file
What I want to do is to convert ...
0
votes
0answers
11 views
Missing raster data from masking with a spatial polygon layer in R
I am fairly new in R and I am trying to create a new raster by using a spatial polygon layer. I have the code written by using the mask function and the output is essentially what I want, but I'm ...
1
vote
0answers
28 views
Move TIFF in QGIS 3.4
I've got a TIFF imported as raster in my QGIS with KBS WGS84. Now I duplicate the layer and want to move that raster to the right edge of the first TIFF. So I just want to move / translate the TIFF to ...
1
vote
1answer
17 views
How to get a frequency matrix of overlaying raster values?
as I couldn't find any solution for this, I ask for some ideas for my problem on this platform:
I have two raster datasets (a World Soil Map and Global Horizontal Irradiance), which I merged together ...
-1
votes
0answers
21 views
QGIS 3.4.4 Fails to mask a Raster
When I use to create a cliped/masked raster from an original one according to the Raster Calculator procedure, it fails.
I wrote my intensity images on a .Geotif file using GDAL in Python. I can ...
2
votes
0answers
34 views
Unable to truly polygonize raster in QGIS
I've used QGIS's Polygonize to convert the following raster into outlines. The polygonize tool does produce a vector output, but it isn't in plain polygon form but some thousands of single pixel ...
0
votes
1answer
27 views
Clip tool in ArcGIS Pro not working?
I'm trying to clip "Terrain" raster I downloaded from the portal (https://www.arcgis.com/home/item.html?id=58a541efc59545e6b7137f961d7de883) in the shape of a polygon (a country's boundaries) by using ...
1
vote
1answer
36 views
How to Export Map Accurately as a Raster Image in QGS 3.4
I'm struggling to accurately export a map I have using QGIS. I am using the Import/Export > Export Map to Image function. My map is based on a 600x800 pixel raster on which I have overlayed other ...
0
votes
1answer
40 views
Extract Raster Information using Python
I would like to extract raster information (i.e. coordinate system, cell size) to excel file using python, how can I do that?
