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

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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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329 views

Single Tree detection

I was wondering how I could extract "crown area" of single trees in a forest from a high-resolution image with only 3 band (RGB) in ArcMap. ( No NIR to use NDVI as any threshold). I need a fast ...
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44 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 ...
2
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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 ...
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67 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 ...
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44 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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320 views

How to Normalize or rescale the NDVI raster image

I have processed my landsat band 3 and band 4 of different years to derive NDVI values the possible values of Normalized difference vegetation index is -1.0 to +1.0. The bands were atmospherically ...
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182 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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296 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 ...
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64 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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35 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 ...
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24 views

Map Algebra with Zero-inflated regression weights

I have a non-normal count variable y and 6 rasters x1 to x6, each mapped onto a (n x n) grid. I have applied a zero-inflated negative binomial regression using the pscl package of R. I now need to ...
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78 views

Kernel Density Estimation Crimestat

I calculated a series of Kernel Density Estimations in CrimeStat (because more parameters can be set than in the built-in tool in ArcGIS) and then imported the results into ArcMap. I wanted to combine ...
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138 views

Why does every raster calcuation I try return with NAN values?

I am trying to work with DEM rasters from the USGS using the raster calculator. I have tried to change the units from meters to feet using an expression such as: "ned10m45111h8@1" * 3.28 However ...
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59 views

How to correctly input complex multiband functions in Raster Calculator?

I'm trying to compute a MTVI2 (Modified Triangular Vegetation Index - Improved) and EVI (Enhanced Vegetation Index) from Landsat 8 imagery. My formulas are as follow (I'm using ModelBuilder): MTVI2= ...
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52 views

How to raster clip in outside in ArcMap?

How to raster clip in ArcMap? But I need 1 raster in outside area. Because 2 raster map. Example: Ras1=Temperature.tif Ras2=Error map.tif Clip command input raster=Ras1 Output Extent= ...
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64 views

Substract 2 rasters with Raster Calculator in ArcObjects (VB.NET)

I'm having a hard time substracting 2 raster with ArcObjects sdk 10.1. I keep getting a nullreference exception at the gp.execute() method, but I can't figure out where the problem is, I recall ...
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67 views

Generating a predictive map with standardized variables

I have a model from which I am attempting to create a predictive map (in GIS, but I'm aware of some options in R). The response values are constrained to [0,1] using an offset term in the model (see ...
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101 views

When subtracting two raster with different cell sizes using raster math, what value is used for smaller cells?

After reading the answer to a similar question (What will happen if we subtract two raster with different cell size using Raster Calculator?), I am still left with a question. When the raster with ...
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165 views

Raster Calculator Error 000539: Error running expression: rcexec()

I am using: ArcGIS 10.2 for Desktop Version: 10.2.0.3348 My assignment requires the use of Raster Calculator to run the following calculation "AccessRaster" == 0 & "Slope" >= 2 & "Slope" ...
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103 views

Preprocessing GeoEye-1 in GRASS iatcorr

I am trying to do a study on land use change using three high-res images of an area from three sources (Quickbird, GeoEye-1, WV-3). I have managed to calibrate the Quickbird data using QGIS raster ...
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125 views

How do you use the Raster Calculator in ArcGIS to combine rasters using the Con statement

So, I'm busy doing an assignment where we have to use a Weighted overlay to generate a raster of suitable places to plant crops. I've put all the factors in the weighted overlay and generated my ...
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106 views

Merging rasters which overlap using ArcGIS for Desktop?

I need to merge two rasters which overlap, both indicate distance values. I need the output of the merge to result in the shorter/lower distance value. I am using ArcGIS 10.1. I hope it is more ...
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142 views

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

First time caller, long time listener.... 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 ...
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117 views

How to calculate the Vertical Distance to Channel Network in ArcGis?

In Saga there is the tool "Vertical Distance to Channel Network". Is there a way to produce the same data in ArcGIs? With con("flowacc" > xx, 1) I was able to create the Channel Network. I am ...
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78 views

Assigning score to raster based on cell overlap with other raster and field value

I have a set of rasters that I've assigned scores to individually (scored based predominantly on values of other fields). The scoring scale is the same for all rasters, but the factors that determine ...
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147 views

Creating a Raster of Road Distance to Point

I am using QGIS 2.6. This question is in two related parts: I'm trying to create a raster of travel time from one point to another point travelling via the road system. Each raster pixel will roughly ...
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110 views

Raster calculation with string in modeler

In my model I have one raster file and also a string input (factor for further calculation). I tried to use the grass r.mapcalculator where I can find the raster and also the string input. I tried to ...
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83 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 ...
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129 views

Raster Calculator

I have a slope dataset. How do I calculate the real surface area for this slope dataset using the raster calculator. This is the example I was given: orthogonal area of a raster cell in square ...
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473 views

plug logistic regression equation into Raster Calculator when one predictor is nominal

I am conducting a study that aims at building a Logistic Regression model for land productivity quality (binary dependent variable: good, no good) using different predictors such as slope, elevation, ...
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125 views

How to produce a hazard map using slope and geology information

for my project I need to display a landscape's susceptibility to erosion. I created a slope-map out of my DEM and added the bedrock geology as a polygon-feature shapefile. Now I want to tell ArcGIS ...
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201 views

Why does the SAGA raster calculator fail when used in a Processing model?

I have a problem with the modeler and the saga raster calculator. When I'm using the raster caculator without the modeler it works fine. When I'm using the saga raster calculator in my model I always ...
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37 views

Layers and variables are not coming out in the raster calculator tool window

I have many shapefiles in the table of content but layers and variables are not coming out in the raster calculator tool window. I placed the cursor the left of the Raster Calculator window, dragged ...
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666 views

How To calculate raster land cover inside overlapping buffer zones?

I am working with a raster land cover file that consists of several land cover types (e.g. forest, buildings, grass ect.) in total there is 40 different land cover types. I have 1200 bufferzonen ...
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493 views

Raster calculator error 000539 - cannot create weak reference to 'classobj' object

I was - like many times before - trying to clip a raster with the raster calculator (raster * 1 with shapefiles as mask). Now - the following error keeps popping up: ERROR 000539: Error running ...
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12 views

Calculating water flooding with raster calculator

I have many layers so i will try and explain what all the layers are. What I want do is enter a calculation in raster calculator to calculate what areas of the map will be flooded if the water levels ...
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14 views

Recover failed raster calculator operation QGIS

Users can recover their raster calculator algorithms via the "results" panel in ArcMap (i.e., analogous to viewing one's "history"). Is there a similar function in QGIS? In other words, is there a ...
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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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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 = ...
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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 ...
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46 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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18 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 ...
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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 ...
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48 views

Can I run hydrology tools within focal statistics?

I've been trying to identify ridges and valleys from a DEM and have been using hydrology tools. I identify rivers as areas that have a value on an accumulation raster above a threshold, then valleys ...
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76 views

Adding rasters with GeoTools

I'm using org.geotools.process.raster.AddCoveragesProcess class, to add two raster's with same resolution and buonding box. I get the following exception java.lang.IllegalArgumentException: Range ...
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35 views

Can I multiply fractions in map algebra?

I have a couple of rasters that show % of success in different things. I want to calculate the overall probability of success. The numerical values are integers so they represent the percentage. This ...
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74 views

How to reclassify raster data that falls within a polygon

Thansk for your response Okay so I will reword my question more clearly I'm currently using ArcGIS 10. My task is to map forest cover with the image classification tool. The problem is some of the ...
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50 views

How can I replicate focalmean with focal statistics

Hi I am trying to get rid of some small gaps of no data in my rasters. I would previosly have used focalmean but it is no longer available. I've tried what I expected to work but I'm getting errors. ...