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Questions tagged [raster-calculator]

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

3
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0answers
114 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 ...
3
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0answers
457 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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0answers
158 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....
3
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0answers
653 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
votes
0answers
33 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 ...
2
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0answers
38 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
40 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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0answers
101 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 ...
2
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0answers
117 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 ...
2
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0answers
156 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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0answers
24 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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0answers
212 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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0answers
76 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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0answers
82 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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0answers
232 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
262 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 ...
2
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0answers
154 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
237 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 ...
2
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0answers
816 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
201 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 ...
2
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0answers
469 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
2
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0answers
440 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
136 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
459 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 ...
1
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0answers
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 ...
1
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0answers
19 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 ...
1
vote
0answers
29 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 ...
1
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0answers
138 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 ) / ( @...
1
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0answers
123 views

QGIS Raster Calculator missing bands

I've created a VRT from some 6-band TIFF tiles. The VRT displays perfectly in QGIS 3.6 and I can see manipulate the band arrangement and create different composites. However, when I open the raster ...
1
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0answers
65 views

gdal_calc.py result are false and not the same as “direct” calculation

I need to do the raster calculator operation as "raster + constant" in Python. The input rasters are DEM data with float original type and -9999 for the NoData. The constant is float too. In 1st way, ...
1
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0answers
70 views

Ordering of Band Import into QGIS Raster Calculator?

I am using QGIS 3.4,3 I want to use Raster Calculator to create NDVIs using Planetscope AnalyticMS_SR.tif I know that the band order for Planetscope is BGRN When I import the multiband SR into ...
1
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0answers
78 views

How can I merge a DEM mosaic with an overlapping bathymetry raster (while keeping only the portions of each that I want)?

I am tasked with merging a bathymetry raster with a mosaic raster I created from ArcGrid DEM Tiles downloaded from the National Map, for an areal extent spanning the Coastal Lowlands Aquifer System. ...
1
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0answers
55 views

Selecting pixels in raster using polygon selection tool in QGIS?

I want to reclassify landcover image manually with respect to online imagery. I am looking for a software/plugin/script to manually select raster pixels using polygon selection tool and could be able ...
1
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0answers
18 views

Adding small-extent rasters to DEM

My goal: create viewsheds for observers which also incorporate the heights of buildings which could block observer view. This is using archaeological data, and is representing time change -- so I need ...
1
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0answers
50 views

Trying to deal with pure whites, and transparency of orthomosaic in MapInfo

I'm hoping to deal with this using the raster calculator in QGIS. But, here's my issue (and I'm a pretty novice GIS user); when you bring a raster image into MI, it turns all the null ("no data") ...
1
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0answers
102 views

Sum multiple raster layer under condition

For a suitability analysis I need to sum up three raster layers a,b,cconsidering different conditions. let's say, output layer is d. I'd prefer Open Source Software, particularly QGIS (with SAGA, ...
1
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0answers
18 views

Error when replacing part of raster with another raster

When using Con(IsNull("replacement_raster"), "full_raster", "replacement_raster") to replace parts of a larger raster with a new smaller raster I get stripes in the vicinity of the smaller raster ...
1
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0answers
66 views

Comparing normalize options of ArcGIS Desktop?

I am wondering if the tool “rescale by function” is definitely doing the same than the raster calculator with the expression ("raster"-min("raster"))/(max("raster")-min("raster"))*100? (I guess so, ...
1
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0answers
69 views

Using the output of zonal statistics in raster calculator

In ArcGIS (10.2) Model Builder, I am using the raster calculator to select a subset of cells from a temperature layer (a range between a max and min value). My expression reads as follows: Con(("%...
1
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0answers
76 views

Iterate a multistep Map Algebra

I am trying to write my first ArcPy script to iterate a Band Math process with requires a few steps. The uniterated, working script for a single group of bands in one Landsat scene is: #import ...
1
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0answers
154 views

Raster calculator: Missing areas in output using two mosaics

I'm doing a simple DEM minus DSM to get tree canopy heights. However my results are missing most of the data (no data). I've used the Minus tool and Raster Calculator achieving the exact same result. ...
1
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0answers
163 views

Conditional in Raster Calculator

I am trying to perform a classification in Arcmap's raster calculator, but it seems that the use of multiple conditional is confusing me. What am I doing wrong in the following con-statement?: Con("...
1
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0answers
161 views

Raster Calculation Using GDAL

I want to perform raster calculation from GDAL tool. I am using the formula as, gdal_calc.py -A Input_File.tif --outfile=yourOutput.tif -- calc="(A>=2200)*A" --NoDataValue=0 --type='Float32' But ...
1
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0answers
236 views

r.mapcalc error, no output

I am getting the following OGR error when using Grass r.mapcalc in QGIS 2.18 on Windows 7: Data source is invalid () The process seems to run, the window shuts but there is no output. This ...
1
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0answers
163 views

Calculating percentiles from timeseries raster data using ArcGIS?

My question is similar with Calculating Percentiles in ArcMap? But I would like to calculate the percentile from timeseries raster data. I have timeseries raster data from 1981 to 2016, its the max ...
1
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0answers
71 views

Raster Subtraction with 2 different sized rasters

I am a beginner to ArcGIS and am using it for my dissertation. I have two raster files of different areas and subtracted one from the other to find the difference between the two, however, it has ...
1
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0answers
243 views

Error 000539 in ArcGIS Desktop?

I am using Raster Calculator in ArcGIS 10.4.1 in order to substract two raster surfaces. However, when I substracted the two surfaces an error 000539 was appeared! I tried to adjust the two surfaces ...