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

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17 views

How to prevent RGB composite flatten to 1 band after raster calculation

I have a series of landsat wanting to process in raster calculator, but after doing the tool it happened these output images only contain one single band. They used to be RGB 3-band images. It is on ...
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1answer
52 views

How to calculate the percentage of cells which are lower than a site in Grass GIS

In GRASS GIS: I have a shapefile with 300 hundred of sites (with height values for each point), and want to calculate the percentage or number of cells (of a given DEM) which are lower than the ...
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1answer
37 views

QGIS Zonal Stats Plugin - Python Console - compute one specific statistic

I think this is more of a syntax problem that I have here. But I am absolutely not able to figure it out. On a different Linux machine I got the following working: zoneStat = QgsZonalStatistics ...
3
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1answer
28 views

QGIS Raster Calculator syntax

I have tried this several different ways and get lots of NaN. I need to specify that in my raster 'test1', I want a certain set of values to equal 1 and the rest to equal zero. For instance, I want ...
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1answer
97 views

Huge file size after averaging two rasters

After I average two raster files (singleband gray, initial size ~700MB each) through QgsRasterCalculator() with formula "Raster1@1/2 + Raster2@1/2" the size of the resulting file is 2.9GB. Is there ...
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33 views

How do I change my “no data” values to get “true” values in raster calculator in Qgis

I have two rasters and I want to subtract the values from one of the layers. The first raster is a altitude raster and the second raster is depth values for a lake. I would like to subtract the depth ...
4
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1answer
19 views

ArcGIS merge/unite two rasters with same extent with RasterCalculator

I've a problem with the ArcGIS Raster Calculator: I have two 2-Bit Rasters with the same extent, the only data stored in it are 1-values and NoData. Now I want to combine this two Rasters: If in ...
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1answer
29 views

Convert 0's to NoData in QGIS Raster Calculator [duplicate]

What is the easiest way to convert cells with a value of 0 to NoData in QGIS Raster Calculator?
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87 views

Sequentially distilling several raster data sets into final map based on first time pixel’s value was greater than zero?

I have 120 daily data sets that contain a value only when a threshold temperature is exceeded. If the threshold has been reached that pixel was assigned a value indicating the day it occurred (the ...
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1answer
27 views

Changing raster value based on point feature

I am working on some landslide modeling. Within ArcMap I have a raster layer, representing the area of the county I am working in, and a point layer that shows landslide locations. I reclassified ...
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1answer
49 views

Using Raster calculator in Modelbuilder ArcGis 10

I am using Modelbuilder to calculate several rasters with different parameters for each grid cell. One of the final steps is to calculate the log of one of the rasters using Raster calculator. ...
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2answers
24 views

Polygon to raster. How to keep same values?

I have a polygon with values 3, 6, 9, 12, 15, 18, 21, 24, 27 an 30. These are the time it takes for the firetruck to reach certain destinations. Now i want to compare these to another raster that have ...
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2answers
54 views

I have slope raster and that is categorized with slope in percentage(%) but my script not successful

I have slope raster and that is categorized with slope in percentage(%) my condition is if slope <= 1 then m = 0.2 1 < slope <= 3 then m = ...
2
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3answers
46 views

Add value to entire column in attributes

Is there a way to add a value to the entire column? I don't think i can use raster calculator because it's a text i want to add, the letter "B". Here is a picture. This is what happends when i use ...
2
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0answers
43 views

Using attribute table values as input for raster calculation - modelbuilder and iteration

I have multiple years of daily XY point shapefiles that contains multiple attributes. I would like to choose one attribute from my XY point and perform a raster calculation with that value and apply ...
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24 views

Performing Raster Algebra using DotSpatial?

I want to perform some Raster Algebra using DotSpatial. Is there any solution for it? Or any examples? this is a class which I am developing to perform raster algabra but as you see there is some ...
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1answer
28 views

Raster calculator iteration

I have a set of rasters within a file gdb in which are of continuous values (NDVI). I am trying to build an attribute table for each raster in order to reclassify into either 1 or 2 (water or land). I ...
3
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1answer
45 views

Polarity of Slope raster for use in Multi Criteria Evalution

I'm looking to use a slope raster in a MCE however i am struggling to ensure it has the correct polarity. The polarity of my other two layers is high values = good and low values = bad. The slope ...
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1answer
27 views

Using decimals in ArcGIS Raster Calculator tool?

I would like to create a new raster by using the following regression equation in the Raster Calculator tool in ArcGIS 10.3: Outputras=0,000826345+(0,000203494*"Roads_density.tif") ...
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2answers
73 views

how to get max and min from a raster using arcpy?

I have a land surface temperature raster file and I want the max and min of it. minLSTresult = arcpy.GetRasterProperties_management(raster_result, "MINIMUM") minLST = minLSTresult.getOutput(0) ...
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0answers
20 views

How to iterate a raster calculator with a change in the input raster and in the values calculated? Than, how to put the results in a table?

What I do without iteration is the following: Change radiance to reflectance for band 3 with raster calculator Samething as #1 on band 4 (the values in the formula are different from #1) Calculate ...
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15 views

How to chain several conditions in SAGA raster calculator

Is there a way to use an AND statement within SAGA raster calculator expression to include several conditions in the same operation? I have 3 rasters, the statment should be: If (A = 0 and B = ...
2
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1answer
58 views

SAGA tools in QGIS only allow save as .sdat file?

I'm just beginning to learn how to use SAGA 2.1.2 tools within QGIS 2.12.1 on a Windows 7 64 bit computer by working through exercises in Mastering QGIS by Menke et al. ...
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33 views

Raster Calculator subtraction giving wrong difference

I'm performing a pretty simple subtraction: The values of the resulting raster are correct for some pixels: But many pixels are calculated wrong: Which settings do I have to change to get ...
3
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1answer
42 views

Standardising DEM raster for a MCE

I'm trying to complete a Multi-Criteria Evaluation for an MSc assessment and am in the process of standardising my factor maps. Unfortunately, my DEM layer (ASCII file) keeps changing from this: ...
2
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1answer
36 views

Raster Calculator to extract elevation and slope conditions in ArcGIS for Desktop?

I've got a DEM ("ASTER_Nepal.tif") and a slope ("ASTER_Slope.tif") and am trying to create a new raster for elevation values between 2000 & 7000m and between 5 & 60 degree slope. I've tried to ...
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43 views

How can I smooth a discrete raster in ArcGIS?

I started with a continuous spline raster of hotspots, classified by standard deviations from the mean. This displays as 7 classes, but since it's a continuous raster in ArcGIS 10.2, it appears nice ...
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1answer
28 views

how to calculate the mean value of pixels of a raster in Grass plugin in qgis?

I am using grass plugin in qgis 2.12. I have to estimate the average value of all the pixels but don't know how to do it.
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1answer
35 views

raster calculator (spatial analyst) tool not working in arcpy [duplicate]

I am using arcpy and while running the script it is unable to find RasterCalculator() method? Even after imporiting arpy module >>> RasterCalculator("IDSI_2002.img + ...
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1answer
22 views

Combine two rasters- only value 1 stays; zeros converted to NoData cells

I am trying to combine 2 rasters: one with values = 1 and the other with values = 0 because I need a final raster with no empty cells. When I use the Raster calculator, the resulting raster only ...
3
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33 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, ...
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39 views

QGIS raster calculator - crash minidump

I'm new to QGIS and using version 2.10.1-Pisa. I have two raster layers created from ASTER DEM data. I have one for slope and want to create a binary layer where only pixels between 8 and 60 degrees ...
2
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1answer
49 views

Conditional statement in gdal_calc with result as float, not boolean

Many examples on gis.se that refer to gdal_calc give a boolean example. example 1 example 2 If I need to calculate a conditional statement on a float: If Raster_Value >= 1024, then 1024; else ...
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1answer
43 views

Determining raster intersection using ArcGIS for Desktop?

Using Arc 10.2.2 with Spatial Analyst, I need to determine the spatial intersection of two rasters (both rasters are in the same coordinate system, and are aligned to the same snap raster). The two ...
3
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3answers
116 views

Flow Accumulation Python or MATLAB Script

does anyone have any resources for scripting the D8 flow accumulation in Python or MATLAB after obtaining the flow direction values and filling in 'sinks' and 'flats'? I am trying to understand the ...
1
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1answer
50 views

Raster processing in ArcPy seems to “simplify”/“round” my resulting values

I'm working off a DEM and doing some raster algebra with it (real simple, add this decimal value, then divide by this value). The DEM in question is super high resolution LiDAR, that's both spatially ...
1
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1answer
54 views

Calculating slope between 5 and 10 percent using raster calculator of QGIS?

I went to Raster --> Analysis --> DEM (Terrain Models) to compute slope. The slope ranges from 0-39.2311. Now I'm unsure of the correct way to calculate slope between 5-10% in the raster ...
0
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1answer
34 views

ArcGIS 10.1 SA Raster calculator: Multi-raster conditional with nodata

I have a question regarding the Con statement when used in the SA Raster Calculator. I am reclassifying a raster (categorical, integer) based on my own mappings but also on another raster (for some ...
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1answer
34 views

Using OR and ISNULL in Raster Calculator

I am using ModelBuilder for ArcGIS Desktop 10.2 I have the following code in the Raster Calcualtor which works in some cases but not in others. Int(Con(IsNull("%A%")|"%A%"== 0,"%B%",float(%Max%) + ...
3
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1answer
37 views

Performing raster calculations along line feature or within polygon using QGIS?

I need to add a value to a dem file along a polyline feature or within a polygon. How can I add 100 to the values of the raster cells intersected by my line feature or within my polygon feature. I ...
0
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0answers
17 views

Mathematical functions in Arcmap's raster calculator - Derivatives & Complex numbers

Is it possible to calculate derivatives and complex numbers on rasters inside the raster calculator in Arcmap ? If not, is there any walkaround ? Also, QGIS or any other opensource software can ...
0
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1answer
47 views

Algorithm for soil texture calculation

Ok. I have percent sand/silt/clay values for 30 sample points on grid. I used these values to create 3 interpolated IDW rasters. I want to somehow (I think in raster calculator) to make a code using ...
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1answer
51 views

QGIS raster calculator error: cannot convert float infinity to integer

I just made a simple subtraction between two raster layers and got the error: Traceback (most recent call last): File ...
3
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2answers
43 views

Using Con in Raster Calculator of ArcGIS for Desktop?

I have two images, "dvel.img" and "evi.img", and i want to extract water related pixels. The condition is: (("dvel.img" <= 0.05) & ("evi.img" <= 0.3)) I want to get an output by putting ...
4
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2answers
76 views

Expand raster nodata area (shrink values area)

I need to fix a raster that's been inappropriately resampled along the nodata edge. The bad data area is narrow, pretty much a single cell. The value range is too variable to use a simple "erase less ...
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1answer
39 views

Raster Calculator Parsing Error

I am using three cons with raster calculator to give four different results depending on the values within two rasters, aclip20151111 and sclip20151111. There are four results I want; RESULTA, ...
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1answer
32 views

Where command in raster calculator Arcgis

I have two rasters that I wish to combine to give a third raster that describes spatially where multiple conditions of both rasters are met. For example, say my two input rasters are raster A and ...
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1answer
18 views

Assign values to raster in QGIS

I'm stack with a simple issue. I have a raster (DEM) and what I want to do is to assign -9999 where the pixel value of the DEM is 500 and leave all the other values as the original ones. I tried: ...
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0answers
18 views

Map algebra with raster [duplicate]

I am doing some map algebra with a raster however the result is not correct. I think it is because the cellsize (x,y) is in decimal degree (0,00027777778, 0,00027777778) and the z values are in meter. ...
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0answers
33 views

Adding Raster by raster calculator gives no values

I`m trying to add several raster files to one (like a merge). I tried using the raster calculator (in ArcGIS 10.2.2 and in QGIS 2.8.1 and QGIS 2.10). Anything I do leads to rasterfiles which have only ...