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

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57 views

Creating an R factor raster in RUSLE Soil Loss equation with multiple input rasters

I am attempting to obtain the rainfall erosivity "R" factor for the RUSLE Soil Loss equation using rainfall PRISM 30 year history data. I have both monthly and annual data that comes into ArcMap as ...
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28 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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1answer
46 views

Create Raster Surface from Points and Equations in ArcGIS

I want to use point data to create a raster surface which distributes the values over space, as defined by an equation, and NOT by interpolating. I have an equation to describe how the characteristic ...
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2answers
162 views

QGIS – Raster Calculator: Using flat (no data) areas of an aspect-raster in the raster calculator

I´m playing around with the Raster tools, following more or less the qgis-tutorial but using my own data. When I calculate the aspect of a DEM, flat areas are (logically) left without data. However, ...
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1answer
35 views

QGIS Raster Calculator, joining two raster

In QGIS raster calculator I do: Plus (+) And I get: The red circle in the middle is like cut in the result, QGIS it's not adding every pixel on each raster, it makes a kind of ...
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57 views

Stream buffer and reclassification

![euclidean distance and the layout highlighted(but they are two different layers)][2]I have this task to perform for hydrology analysis as presented below: DETERMINATION OF STREAM NETWORK AND ...
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31 views

Raster layer - changing values in raster cells

I have a lot of cells in a raster layer (GeoTIFF) with a -9999 value in it. I would like to update that values to 0. I mean, in vectorial layers would be something like: CASE WHEN band1=-9999 THEN 0 ...
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698 views

Raster Calculator Workaround in Arcpy for Suitabiliy Analysis

This is my first attempt at a complex stand alone python code. I am self teaching the arcpy module, well at least attempting to. I am having a great deal of difficulty getting my site suitability ...
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1k views

Piping output of Iterate Raster tool into Raster Calculator tool using ModelBuilder?

ArcGIS v10.1 ModelBuilder Using ModelBuilder and map algebra, I want to compute a ten year average grid from a stack of 10. The problem is that only 1 grid (%raster%), the last one through the ...
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796 views

How to “spatially normalize” rasters of different extents to sum values of overlapping cells

How do I add rasters together that are of different spatial extents? I have many, many features that overlap over a large area (entire east coast) and I am looking to sum them "stacked" where they ...
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35 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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237 views

How to find buffer radius around raster cell that covers a defined sum of raster cells?

I want to do a neigbourhood analysis on some raster data. I need to know how big a circle around each raster cell must be to include a certain amount of specified raster cells. Let's say that for ...
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28 views

if condition is false but output is true . what is the exact expression of greater than to bands value ('mjune@1'> 99.6:)

from qgis.core import * from qgis.gui import * from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry from math import * from PyQt4.QtCore import QFileInfo import os from osgeo ...
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1answer
115 views

What will happen if we subtract two raster with different cell size using Raster Calculator?

I want to subtract a topography raster with a depth raster. The problem is the two rasters have different cell size. The topography raster have a square cell size of 5, 5 while the depth raster have a ...
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99 views

Calculating average raster grid values perpendicular to a barrier and transferring values to adjacent cells

I was hoping I could get a little help for 2 questions dealing with raster datasets. I have access to ArcMap 10.2 and ArcView 3 to do this. Here is what I am trying to do: 1) I need to calculate an ...
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129 views

QGIS 2.4; How to convert float raster to integer raster

I am using Normalize difference vegetation index (NDVI) derived from the landsat satellite band 3 and band 4 that have float values ranges from -1.0 to 1.0. I want to see the attribute table that is ...
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67 views

How to sum 10 raster bands instead of 9 from code?

I want to sum 10 raster bands but the problem is that the following code will only work for summing 9 bands, which means the output image consists of 9 bands. from qgis.core import * from qgis.gui ...
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1k views

How to evaluate raster calculator expressions from the console?

How can I execute from the console an expression that should be used with the raster calculator? I'm searching for something like this: qgis.someRasterCalcClass.evaluate("boh@1 + boh@2", ...
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85 views

Raster Calculator with conditional arguments?

I am trying to create a binary raster using the Raster Calculator in ArcGIS 10.2. I have a raster with ~20 different values, but I'm only interested in cells where the value = 10. I've been using the ...
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1answer
35 views

If statement using QgsRasterCalculator

So in the sequence of my previous question (Can't use Raster Calculator with two different rasters), I am stuck again in my project. With my source rasters, I created 3 different outputs using ...
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50 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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35 views

How can i perform area calculations in a raster file?

I would like to know if is possible and how can i calculate all areas or parts of it in one raster? Can i do it using the raster calculator? All help is appreciated, Best regards
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52 views

byte swap a mosaic raster

I'm getting into trouble to byte swap a raster. I'm using two DEM rasters that I mosaic using the function "mosaic to new raster". The new raster I get is called "mosaic". The cell range then shift ...
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93 views

weighting and combining data sets in Raster Calculator

I`m having problems using Raster Calculator to create a final cost raster. I have to add 7 raster data sets together and multiply each of them with the correct weight. The resulting raster is ...
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43 views

Animating alterations to DEM based on function using ArcGIS for Desktop?

I've generated a function that alters height values of a DEM based on certain criteria. What I'm looking at doing now is animating this in ArcScene. Is there a way, in ArcGIS, for each frame to be the ...
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3answers
78 views

Raster calculator to create single raster with 4 values from two binary rasters

I have two binary rasters showing habitat suitability (0 = unsuitable, 1 = suitable) under current and future climate scenarios. I am trying to create a raster showing: 0 = cells that are not ...
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163 views

Can't use Raster Calculator with two different rasters

So, I have several maps like this one: And with the proximity tool and a coastline shapefile I made this output, representing the distance to shoreline: Now, I want to combine both using the ...
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1answer
33 views

Error summing 2 different rasters?

I was trying to sum two different rasters and the final outcome is an error (image attached below)? The main goal is to sum the values of each pixel in those rasters (both raster files have the same ...
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1answer
95 views

How to select a part of a land cover type a certain amount of feet away from another land cover type

I have raster Landcover type Urban combined with Forest all within the county raster perimeter. I want to make a layer of only the forest cells that are more than 500 feet from an urban cell, so that ...
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2answers
102 views

changing pixel values using raster calculator Qgis

How could I convert a value of 32767 to a 0 using raster calculator in QGIS?
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176 views

Exclude Raster Cells with Value of Zero in ArcGIS 10.2 Raster Calculator Expression

I need to perform a simple calculation in ArcGIS 10.1 Raster Calculator. I am using a raster layer that contains many cells that have a value of zero. I need to exclude these cells in the expression ...
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17 views

Rastercalc.py and Rastercalcengine.py

Is there any examples on how to use the rastercalc.py or rastercalcengine.py? And what are the purpose of these python module? Are these modules the same with gdal utilities which can be run in ...
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1answer
146 views

How to subtract out the slope (in general) of a DEM?

I'm searching for a solution process to subtract out the slope of a DEM like this: I have a high resolution DEM and want to reconstruct historical/old/not active parts of a river. The problem is ...
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1answer
393 views

Floating point calculations in QGIS

How do I manage floating point calculations in QGIS? I have carried out 3 consecutive calculations on landsat bands. I end up with 32 bit floating point rasters on which I can't carry out a 4th ...
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2answers
162 views

Querying slope data using raster calculator: why are all results true?

I am using ArcGIS 10.2.2. From a DEM, I have created a new raster showing slope using the slope tool. The color scheme was automatically classified into 9 tiers. What I want to do is query this raster ...
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1answer
128 views

How to make a new raster out of two other rasters [duplicate]

I have two raster images, one is the Corine Land Cover for the year 2000 and another one which is the anthropogenic effect on land. The first image reclassified in 9 categories: Artificial surfaces ...
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2answers
289 views

Raster calculation confusion

I need to do some raster calculation, I've been trying to make it work but I am not sure everything is working properly. I need to apply a formula, but I am unsure if I am doing it properly. The ...
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1answer
849 views

Problem with raster calculator [closed]

When working with raster calculator there is an error 000539? The program failed to create a common raster map. I don't know what to do. I did the same in school without any problems. But now, on my ...
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1answer
239 views

GRASS 7 - raster calculator “and”

I am struggling with one thing in the raster calculator in GRASS GIS 7: I want to create a raster_b from raster_a, with raster_a values between >=-0.15 and <=0.15. The raster containing values ...
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2answers
123 views

How to automate creation of toe of slope from DEM?

I was looking for an automated process to "identify" the toe of a slope from a DEM and ran across this ESRI thread and technique: I am at Step 7 but have no idea how this is accomplished. I get it is ...
2
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1answer
97 views

Raster Calculator Syntax - ArcGIS

I'm trying to reclassify a raster based upon two criteria 1. Raster cell on "CBH" is less than or equal to 2 AND "footprint" is not null. Then output raster reclassifies any cell inside this criteria ...
4
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1answer
68 views

Iterate through rasters in subfolders using Model Builder

I have a directory folder of precipitation data; within this folder are subfolders for years 1901-2014. In each of these subfolders are 12 .asc grid files; each file represents a month of the year ...
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1answer
181 views

How to round up/down an pixel value of a raster to a pixel value with 2 decimal places?

I have a raster (DTM) with floating points as pixel value. Now i want to round up/down the pixel values (to its next nearest value) to 2 decimal places. I use ArcGIS (with extensions) and tried the ...
4
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1answer
1k views

Python syntax error from raster calculator in ArcGIS ModelBuilder?

I am experiencing a problem with the raster calculator in the ModelBuilder under ArcMap 10. I need to combine two layers: a drainage map (issued from a series of previous operations on a DEM) and ...
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1answer
167 views

Calculating average NDVI

I would like to calculate average NDVI values. I have 3 values of NDVI: high:243 low:0 high:243 low:0 high:238 low:0 How can I use a a raster calculator to calculate the average valvue
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78 views

Classify Output Raster as percentage in arcGIS

I have water supply and water demand rasters.They are both of the same cell size and spatial reference. I need the ratio of water use to water demand. Then I want to classify this output in the ...
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52 views

Raster Calculator returning nodata for overlaying cells

I used raster calculator to divide two rasters setting the environment to intersection of inputs. The output has a nodata value in a cell where these two rasters clearly intersect. Any suggestions ...
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2answers
63 views

Remove sections, defined by a line or polygon, from a raster in QGIS

(QGIS 2.6.0 on Windows.) I have created a raster layer of heights using the TIN interpolate function. I also have another raster layer with more accurate information on the height of particular areas ...
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1answer
73 views

Modifying raster values in a zone with a math expression

I'm currently doing an SIG project with the goal of calculating groundwater volumes in chalk and silex residuals aquifers. I have point data of underground water, chalk roof, and floor elevations, as ...
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77 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 ...