Questions tagged [raster-calculator]

A tool in some GIS software programs for performing algebraic operations on rasters.

147 questions with no upvoted or accepted answers
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31 views

Multiple conditional statements for raster calculation in R

In the context of a RUSLE erosion modelling I would like to calculate the sum of precipitation at the entry date of phenological phases. Suppose I have 13 grids, one of which is the phenophase entry ...
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137 views

Qgis3 APIbreak : QgsFeedback instead QProgressDialog while using QgsRasterCalculator

I upgraded my Qgis to 3.0.1 and I try to upgrade some of the plugins I wrote. I have a plugin which uses GDAL/rastercalculator from several raster layers to get new informations. With Qgis2 api it ...
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529 views

Difference between gdal_calc and QGIS raster calculator

I am hoping someone can help me with an issue I am having with gdal_calc. I am looking to create NDVI rasters from 4 band 8 bit ortho tiles. I have processed the tiles using the following calculation: ...
3
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162 views

Raster calculators in SAGA return incorrect results

Here's a sample of my dataset (one cell) with 28 different raster values, representing 28 individual Float32 rasters with identical parameters. 0.0000264434, 0.0049953502, 0.0007529828, 0....
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666 views

SAGA Raster Calculator, ifelse doesn't return specified value exactly

I am using the SAGA Raster Calculator in QGIS 2.6 to change NaN values to zero and that part is working great, however the specified 'if' value is being altered slightly. I have developed a work ...
2
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0answers
36 views

Writing Raster Calculator Expression?

I use ArcMap 10.3. How do I create an expression in RasterCalculator that allows me to sum up 4 rasters (every pixel has an associated value) and the result to be 0 if any of the 4 values is 0? For ...
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0answers
40 views

Confusing result of raster calculator in QGIS

I'm confused about the results that I get from the raster calculator in QGIS. I'm trying to delete the cells of a raster who are prone to flooding. However, a part of my raster is wrongly classified ...
2
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0answers
221 views

QGIS RASTER CALCULATOR - Getting the Minimum and Maximum Values of a Raster Layer

I try to work with the minimum and maximum values of a raster layer in the raster calculator in QGIS 3.6. I try to do the following formular: ( @RasterCellValue - @RasterMinValue ) / ( @...
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41 views

QGIS Problem adding two rasters

I have a DEM of terrain that I have successfully added a raster of woodland to: I am trying to add to that a raster of a built up area, but the extent of the settlement raster is smaller than my ...
2
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2answers
65 views

Extracting a single value to a new raster from a singleband pseudocolor raster image

I have a large raster image depicting land use. It's a singleband pseudocolor image whose values are contained in a text file. There are 5 classes. Following the example of this question I thought I ...
2
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0answers
130 views

Why is Raster Calculator not honoring compression environment settings?

For some reason, the Raster Calculator isn't honoring any Raster Storage environments that I have set. Mainly, compression and pyramids. I am processing a large raster dataset through raster ...
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133 views

Calculating indices such as NDVI or NDSI on Landsat 8 imagery whose pixel type is 16 bit signed integer?

I am trying to calculate an NDSI (Normalized Difference Snow Index) using Landsat 8 OLI level 1 imagery atmospherically corrected in ERDAS ATCOR using raster calculator in ArcMap. NDSI is used to to ...
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171 views

Alternatives to QGIS raster calculator?

I am using QGIS 3 on a Mac. I have a large raster (bfd.tif size is 26000, 31800) that I'm trying to apply a calculation to. When I use the default raster calculator in QGIS 3 I get a raster back with ...
2
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28 views

Increasing raster exent with Raster Calculator is modifying band range

I have a TIFF with a single band 16bit signed. I used the Raster Calculator tool to extend its extent: Con(IsNull("mytif.tif"), 1, "mytif.tif") Using ArcGIS Pro 2.0.0 I set the environment to the ...
2
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233 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 ...
2
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2answers
972 views

ENVI band math incorrect values

I'm attempting to calculate vegetation indices in ENVI 5.2 using level-2 AVIRIS data in band math. The indices I'm working with are Vogelmann Red Edge 2, normalized difference red edge, and red edge ...
2
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80 views

Memory Error on QGIS rastercalculator from console

I am experiencing a weird problem using QGIS on Mac. I have been using RasterCalculator from the python console until yesterday without any problem, but yesterday my QGIS crashed while running a ...
2
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0answers
44 views

Finding the optimal boundary polyline in QGIS

I am looking to find an optimal boundary line between two geographically separated sets of points (a vector layer with S and N points representing two genetic lineages within a species). I would like ...
2
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1answer
98 views

Transposing raster values on the fly in QGIS

Say, I have a raster with some annual statistics data. Then Daily avg = Annual / 365 Weekly avg = Annual / 52 Monthly avg = Annual / 12 I know I can do this via Raster calculator in QGIS (v2.18.15)...
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0answers
85 views

Visualizing Strahler-Order bigger than a specific value

I try to visualize the Strahler-Order bigger than 8 using raster calculator. I changed the style of the raster by changing the render type to singleband pseudocolor and, in the colors selector, I ...
2
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1answer
147 views

Which output data type to choose in QGIS SAGA Raster Calculator in Batch Mode?

I have 5 years of MODIS13Q1 NDVI .tiff images for time series analysis. I want to multiply all the images with the scale factor of 0.0001 before using them. In order to process all at once I try to ...
2
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0answers
244 views

Breaking single large raster into NumPyArrays using arcpy memory error

I'm trying to run raster calculator on a large raster file using the following approach : http://pro.arcgis.com/en/pro-app/arcpy/functions/rastertonumpyarray-function.htm, but I seem to run into ...
2
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0answers
273 views

Raster Calculator produces nan results for some multipliers

I am trying to convert a DEM file from meters to feet using a fairly simple formula. The range of elevations in the source file is 551 - 1250. When I multiply by 3.28 I get nan results. When I ...
2
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0answers
28 views

What are calculation methods to remove moire on raster grid?

Here's a raster that I calculate in PostGIS. There are points of residential bulidings with population values P, and businesses with some value to them, say X. I calculate Sum(X) / Sum(P) for ...
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0answers
162 views

QGIS SAGA Raster Calculator returns incorrect results

The SAGA Raster Calculator within QGIS produces wrong results probably due to interpolation but works corretly withion SAGA itself. The problem has been discussed here before but sofar I have not ...
2
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0answers
243 views

Looking for a raster calculator C# class

I am developing an application using C# and dotspatial. I need to performs raster calculation a lot..I need a library which helps me to do it..Do you know any library for this purpose? The library ...
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0answers
866 views

QGIS RGB image to HSL (Hue Saturation Luminance)

is it possible using QGIS (2.10) on windows to convert an RGB image file to HSL (Hue Saturation Luminance) format. I've seen various formulas for this written in Java however they only seem to be for ...
2
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0answers
204 views

Where to find QGIS geoprocessing results?

Is there a way to access in QGIS 2.6.1 something like the Geoprocessing Results window found in ArcGIS? The History and Log window in QGIS appears to show the geoprocessing results from SAGA, OTB ...
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0answers
471 views

Merge Raster Layers with Raster Calculator

I am looking to merge three raster layers together, we are only allowed to use the Raster Calculator tool in Spatial Analyst, ArcToolBox. Using ArcMap 10.2
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0answers
446 views

Why do comparisons in QGIS 2.4.0 Raster Calculator return -3.40282e+38 aka no_data?

I tried to use comparisons as conditional statements in QGIS 2.4.0 raster calculator. My statement is: (a < 230) * 230 + (a >= 230) * a The expected result is raster a with all values lower ...
2
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0answers
140 views

Multiply Rasters with Scalar Numbers as Input in QGIS Modeler

I built a little model in the QGIS modelbuilder which uses the raster calculator with the command gt(a,threshold) I need to run the model with varying thresholds from 2 to 30 so it would be great ...
2
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0answers
468 views

GRID ERROR in raster calculator of ArcGIS Desktop?

I wrote and ran this formula in raster calculator in ARCGIS. But the following error gets me into trouble. Does anyone have a suggestion to overcome this? Here is the formula I wrote and the error ...
2
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0answers
68 views

How do I make a path cross the most possible classes in a raster?

I want to create a function and possibly use Arcmap tools to create something similar to Cost Path. Instead of just choosing the LCP, it must cross through the most different integers. Let's say I ...
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0answers
29 views

Multiplying two iterating rasters in ModelBuilder or Python?

I have several Landsat scenes that I wish to remove clouds from. I can do this by multiplying the Landsat layers by their associated cloud layers in the Raster Calculator. How can I set up iterations ...
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28 views

Problems with Zonal Statistic in graphical modeler QGIS 3

I want to make an average of two rasters previously generated in a model but it always gives error. I have used both SAGA and GDAL to calculate the raster out of graphical modeler without problems, ...
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16 views

Raster Calculator in the Graphical Modeler of QGIS 2.18

How to convert this expression from raster calculator ("noise_heatmap_clip@1" <= 50) * 5 + ("noise_heatmap_clip@1" > 50 AND "noise_heatmap_clip@1" <= 100) * 4 + ("noise_heatmap_clip@1" > ...
1
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1answer
63 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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0answers
35 views

Getting ERROR 000539 running Raster Calculator in ModelBuilder?

I am trying to run Raster Calculator in ModelBuilder, however I am getting what looks like two errors after my model reaches a certain step: ERROR 000539: Error running I'm not sure if it is a ...
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0answers
39 views

Raster statistic

i'm try to use QGIS processing modeler but I've a problem. I need to use the Mean value and the standard deviation in raster calculator algorithm. I've calculated it in raster statistics, how can I do ...
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0answers
30 views

Calculating NDVI values for specific zones using zonal statistics using QGIS

I am currently working with multispectral data from a MicaSense RedEdge M on a plot size study in wheat research plots. I want to conduct zonal statistics to calculate NDVI for individual plots. I ...
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0answers
33 views

All 0s result from raster calculator in python

Raster calculator is not working correctly for a single calculation using a standalone Python script. I am trying to add 1 to a pre-existing raster. It processes, but the resulting tiff file is all 0s....
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0answers
23 views

Join DEM and GPS data point ArcMap

I have a problem using ArcGIS. I have generate a DEM raster with a 3D online software and exported it in ArcGIS. So I have a raster of my surface. After that, I have some GPS point (x,y,z) that we ...
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0answers
16 views

Calculating the distance of raster cells from a vector within a polygon using QGIS

I am quite new to QGIS and am trying to use QGIS 3.6 to create a raster layer of calculated values of the minimum distance of each cells within a polygon (orange) from a vector (the river channel in ...
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0answers
27 views

Raster calculator giving different results in ArcPy than in ArcGIS?

I have two rasters representing travelling speed: one for road (with speed values for different types of roads and "0" values where there is no roads) and one for land-cover (with lower values, but no ...
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0answers
25 views

Reprojected raster return only zeros from QGIS raster calculator

I am experiencing an issue when trying to use my reprojected raster in QGIS raster calculator; First, my raster is reprojected from degrees to meters. After that, I want to process the layer by ...
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0answers
34 views

How to use the Raster Calculator in PyQGIS (Console) in QGIS 3?

I want to use a script to do some raster calculations. I found this and this posts which seem to answer this question, however, it seems that they work for QGIS 2 and not for QGIS 3. I think the ...
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1answer
69 views

Using ArcGIS Pro raster calculator to give cell value based on cells in its neighborhood?

I have a land cover dataset, I want to find forested cells that are adjacent (touch) agricultural cells. Is there a way I can achieve this with the ArcGIS Pro raster calculator?
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12 views

Discrepancy between raster calculator and geomorphic change detection elevation change results

I am using two rasters to determine the elevation change in a stream channel. When I used the Geomorphic Change Detection Software add-in (version 7.4.1), I got a high elevation change of 8.8 ft and ...
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0answers
24 views

Attribute Table missing After Raster Calculator?

I want to remove zero value pixels from MODIS LST raster images and apply a moving window that can only substitute the missing values and leave the other original values with out alteration. I have ...
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0answers
33 views

Checking for exact value in QGIS raster calculator

I would like to single out values which are equal to a certain floating point value using QGIS raster calculator. I tried to run the following: "Converted@1"==-3.40282347*10^38 But I got the error ...