Questions tagged [raster]
Raster is a data format consisting of regular grids of values, usually stored in an image-like format.
6,819
questions
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15 views
Automatize DEM building using QGIS
I use several layers:
Raster: DEM
Vector points
Raster: ORtho
My aim is : for each feature of points (layer: vector points), using the value of the column named "min_Z" to :
Create a new DEM with ...
0
votes
1answer
27 views
Merging rasters orthophoto overlapped with different resolutions using QGIS
I use 2 rasters orthophotos .TIFF :
1) the low resolution covering a large area.
2) the high resolution covering a small area and using an alpha band around the point of interest.
My aim is to merge ...
0
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0answers
12 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?
0
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1answer
25 views
What is combine function in QGIS?
There is combine function is ArcGIS which combine multiple raster value attributes in one raster layer. I would like to know what's the same process in QGIS?
2
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0answers
16 views
Clearing raster layers in QGIS
I have TIFF raster layers in QGIS project. I need to 'erase' them ( like in MS Paint ), clean them of any smudges from low scan. I do not see a proper 'eraser' tool like that in QGIS. How can I remove ...
0
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0answers
14 views
Raster File Clipping
I am trying to clip a raster image with the outline shape of a country, I imported the .png image in using the georeferencer plugin. I then selected the country I wanted to use and saved it as a ...
0
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0answers
25 views
Create a land-use raster in which the “crop cells” are distributed in dependency on the slope?
I have a geo-"scientifical" question. If you don’t know the answer, but have a hint how to search for the solution, this information would be helpful as well!
In Germany we do not get land-use data ...
1
vote
0answers
24 views
Calculating NDVI using ArcPy
I have a custom function that I'm trying to write (using Arcpy in ArcGIS 10.7.1), but I'm having a little trouble writing a successful function because I'm new to custom function writing.
I want the ...
1
vote
1answer
26 views
Replacing cloud values with NA in a raster stack
I am removing clouds from a raster stack of 768 pixel_qa bands which are provided by USGS as part of surface reflectance product. The details of raster stack (qa) are:
> qa
class : ...
0
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0answers
13 views
Creating mask of certain value from classfied raster in python [closed]
I have two classified raster images. I want to create a cloud mask of certain value (like- 120 pixel value) from first classified raster and apply the mask over the 2nd image so that I can compare ...
2
votes
0answers
30 views
Calculating indices by Multiple polygons
Is there a way in QGIS to perform band math within each area defined by different polygons without clipping the rasters and performing calculations on each one?
I have a vector layer with several ...
-2
votes
0answers
16 views
Convert image or simplify [duplicate]
What is the procedure for transforming one image into the other?
0
votes
1answer
10 views
Huge processing time for gdalwarp command extracting ROI by extents
I'm running the below gdalwarp command to extract a 1024 x 1024 ROI from a large raster which has Dimensions X: 34396 Y: 36707 Bands: 4
Input raster has previously been pan-sharpened and ...
1
vote
1answer
15 views
sf polygon to raster workflow to calculate least cost distance with gdistance in R
I need to calclulate the shortest distance from a set of points to other sets of points in a marine area. Travelling on land must not be possible so I understand I need to calculate the least cost ...
1
vote
0answers
12 views
Defining invalid regions of VRT file with rasterio in a way that allows windowing [closed]
I'm using a VRT file to represent a bunch of individual map tiles as one big image. I noticed that some of the data is invalid but not marked as such (via the invalid data value). I'd like to define ...
0
votes
2answers
48 views
Processing images with file type .ntf [closed]
I am use to posting in Stack Overflow, but it seems this question is best geared towards the GIS Stack Exchange. I need to understand the .ntf file types for satellite images. I am in grad school and ...
2
votes
1answer
33 views
NameError: name 'exponential' is not defined
I am trying to do a raster calculation in the QGIS 3.7 python console, using the following code:
import gdal
bf_thickness = "D:\Minnesota data\Data files\clipped\Buffalo_thickness.tif"
bf_capacity =...
-4
votes
0answers
21 views
Principles of navigation [closed]
The distance between two points is 1200 miles. Both points are on same lat of 45 degrees north. What is the rhumb line distance between the two points?
1
vote
1answer
34 views
ArcGIS Raster Calculator Erase raster from raster
Two rasters
slope (black and white grid with slope values)
rasterized property (red, values do not matter)
I want to erase the red raster from the slope raster
I found this thread
https://...
3
votes
1answer
81 views
+50
PostGIS erase/difference vector polygons from raster
I have a raster and a vector table in Postgres 12 PostGIS 3.0
The vector polygon(orange) overlaps the slope raster(grid in black, whiteish)
All I want to do is cut out/erase the orange polygon from ...
2
votes
1answer
38 views
Obtaining slope and aspect for points in QGIS
I'm new to QGIS.
I have GPS points uploaded to QGIS and a ⅓ arc-second DEM (USGS) of the area. I'd like to generate slope and aspect data for each point.
What is the best way to do this?
The ...
0
votes
0answers
9 views
Plot different Layers from `RasterStack`-Object in R
Is there any way to automatically plot each layer from a RasterStack in R. I'm a little bit lost in the vast amount of options. There is tmap, mapview and also leaflet...
For example if you have a ...
1
vote
1answer
32 views
Building Raster Attribute Table (RAT) from GeoPandas dataframe with rasterio or GDAL
I am trying to figure out how to generate a RAT for a 1-band raster with rasterio or GDAL given a GeoPandas dataframe.
My GeoPandas dataframe has 4 columns (X, Y, PERC_VALUE, LANDUSE_LABEL) which I ...
1
vote
1answer
40 views
How to make a polygon from contour lines extracted from a raster QGIS 3.6?
I'm trying polygonize the elevation level 200 m of Europe map from raster GeoTIFF (The raster is projected in EPSG:3120).
At first I tried with Raster > Extraction > Contour, but the lines are ...
2
votes
0answers
32 views
Raster data does not clip to the vector polygon boundary
I am trying to clip a raster to vector polygon. I am using "Extract by Mask" tool and my output raster layer is, what seems like, randomly cut off in the middle. My processing extent is set ...
0
votes
0answers
45 views
UTM points from CSV end up in wrong location [closed]
I have a CSV file uploaded with UTM coordinates that should be located within Botswana. However they show up in the Indian Ocean and in Nothern Europe. We have tried standardizing the crs but it still ...
0
votes
1answer
25 views
Fill raster nodata from other rasters
There are 5 rasters: r0, r1,r2,r3,r4 with same extent, columns and rows. Random nodata cell disperse in each raster. Now I expect to fill nodata values of r0 with mean values of the other rasters in ...
1
vote
0answers
37 views
Raster file not overlaying to vector layer
I'm pretty new to GIS and following a tutorial using shape files from Ithaca, NY. I've been able load a number of vector files easily enough but when I add in the .dem raster file it keeps being ...
0
votes
1answer
29 views
MCARI vegetation index in ArcGIS raster calculator
I'm trying to write the equation for the MCARI vegetation index in raster calculator using WorldView-2 imagery, but can't get it right. Here is the original formula:
MCARI = [(RedEdge – Red) – 0.2 × ...
0
votes
0answers
23 views
When creating a Nearest Neighbour from xyz, the raster cells are not centered with the original point cloud (QGIS)
I have a gridded point cloud 0,25x025. I ran a Nearest Neighbour with the same resultion (cell 0,25). The points of the cloud and the raster are not centered as seen in the picutre. Am I doing ...
2
votes
0answers
26 views
Checking raster value type in QGIS
I naively assumed that the rasterType() function would give me the data value type for the raster (i.e. integer or float), but it just tells you whether it's a singleband or multiband raster.
Is ...
0
votes
2answers
53 views
Obtaining elevation data for points using QGIS [closed]
I am new to QGIS.
I have points uploaded to QGIS that were collected from a GPS, and I need to get elevations for each point (I don't trust the elevation estimations of my GPS).
What is the best ...
2
votes
0answers
31 views
Plotting GoeDataFrame on a raster
I have a bunch of polygons which I loaded from a shapefile into a fields GeoDataFrame:
geometry raster_val
0 POLYGON ((8.56799 47.80800, 8.56799 47.77200,...
0
votes
1answer
23 views
Standardized Precipitation Index (SPI) equation using ArcGIS Desktop
I usually calculate monthly or 3-monthly Standardized Precipitation Index (SPI) using spreadsheet, based on daily rainfall from weather station. Attached is the spreadsheet example link.
And now I ...
1
vote
0answers
29 views
Converting latitude/longitude pairs into gridded Web Mercator GeoTIFF [duplicate]
I have a set of data that is essentially an array of coordinates (WGS84) and values.
Example:
51.5834,-101.1709,0.0452,51.5834,-101.1567,0.0648,51.5834,-101.1425,0.0339,51.5924,-101.2133,0.0339,...
0
votes
0answers
21 views
Reprojection of Landsat 8 using the existing shapefile in ArcGis
I have downloaded a landsat8 and when I overlay it with a shapefile of the location where I want to extract by mask , the combination of landsat 8 and the shapefile are not matching. The shapefile is ...
2
votes
0answers
20 views
How can I fill empty raster cells with values from another raster in QGIS?
I have 2 rasters:
1 that has many gaps in between pixels:
And one that is more filled:
I want to fill the empty cells from raster 1 with the cells from raster 2. Cells that are filled in raster 1 ...
0
votes
0answers
22 views
Python GDALwarp cut a raster with a shapefile polygon
I am trying to create a program that cuts multiple rasters in different folders with gdalwarp, the program works for square shapefiles but when I enter one with a polygon the program does not cut ...
1
vote
1answer
38 views
Unexpected results for area calculation on two datasets in Google Earth Engine
I'm seeing a very strange result using .pixelArea() on two different layers that should yield identical results.
Code within GEE is here, also reproduced below:
var states = ee.FeatureCollection("ft:...
1
vote
1answer
27 views
Better resolution of my raster
if I am merging my raster files or if I am creating a virtual raster, the quality is not as good, as the input rasters on their own. Before:
As a virtual raster:
Does somebody know any tips or ...
0
votes
0answers
31 views
Distance to value pixels by route
I have polygons layer (around 300 watersheds), points layer (boat route, contains around 20000 points) and land-use raster (modified from CORINE according to the local features, contains values ...
-1
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0answers
36 views
3
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0answers
27 views
Exporting rendered raster image from graphical modeler
I am new to using the graphical modeler and am trying to export the result raster from my model as a rendered image.
Basically trying to replicate what happens by doing the following to the result ...
1
vote
1answer
45 views
Display legend/value when hovering over raster layer in QGIS
Is there a way for this and how would I approach this? This would be in the normal map view and not in layout mode. It would be very hand if you have a lot of raster lays in one project and want to ...
1
vote
1answer
38 views
Can't use Raster with vector layer
I'm trying to clip a raster layer with a vector layer, but openlayers seems to fail when it tries to call getImage on the vector layer?
What am I doing wrong?
proj4.defs('EPSG:3006', '+proj=utm +...
1
vote
0answers
32 views
Mosaicking many rasters with large empty raster in R
Following my previous question (Subtracting rasters with different dimension, origin and extent in R), I am trying to mosaic many small glacier rasters into one large empty raster which I can then ...
3
votes
1answer
65 views
Which affine format to use in Rasterstats zonal_stats?
I am working with the Rasterstats package to run zonal statistics on two raster datasets. The documentation calls for the following:
import rasterio
from rasterstats import zonal_stats
with rasterio....
1
vote
0answers
14 views
Erase pixels in a Polygon in a Huge Raster Dataset in ArcMap [closed]
I've a huge raster dataset and I have to replace a small portion with new data. I tried several things to remove related area to upload new raster but I couldn't have any success.
I'll try ArcPy ...
1
vote
0answers
38 views
Subtracting rasters with different dimension, origin and extent in R
I have a large DEM raster from which I want to substract lots of smaller glacier rasters. Examples for the glacier rasters and a subset of the large DEM can be found here: https://drive.google.com/...
2
votes
1answer
24 views
Use column from Raster Attribute Table as Legend in Leaflet Map
I have a simple RasterLayer in R. I added a column to the attribute table and would like to use these values in the legend of my leaflet-map.
The RasterLayer looks like this:
> layer1
class ...
