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

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20 views

Doing same calculation on different Raster files?

I am doing the work of change all null pixels to a value of -1 in the raster file X with raster calculator by using following syntax: Con(IsNull("X"),-1,"X") However, I need to do the same work on ...
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11 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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22 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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77 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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37 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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2answers
48 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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1answer
45 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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52 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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35 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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22 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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64 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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25 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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3answers
58 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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1answer
41 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
63 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
30 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
58 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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2answers
50 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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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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110 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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2answers
92 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
77 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 ...
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1answer
48 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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57 views

Using iterator in ModelBuilder for groups of rasters

I'm trying to do some raster calculations on Landsat imagery in ModelBuilder. I'm calculating basic indices using Raster Calculator followed by Zonal Statistics. The resulting tables are merged ...
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1answer
41 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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38 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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1answer
126 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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43 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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2answers
40 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
63 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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50 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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2answers
55 views

Using QgsRasterCalculator

I'm trying to make a sum of n rasters and create a new one using QgsRasterClaculator, the problem is, every time the code reaches processCalculation, it makes QGis close and create a dump file. I ...
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1answer
43 views

Only run r.neighbors if cell meets criteria

This is my first time using GRASS to work with Rasters, so please excuse my lack of knowledge on the subject. I want to run the GRASS r.neighbors function on cells that meet a specific criteria, ...
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1answer
177 views

Why is the result of a raster calculation integer when it should be decimal?

I'm trying to calculate the NDVI using raster calculator, but the result is integer instead of decimal. NDVI = (NIR - RED)/(NIR + RED) The result is normally in the range -1 to 1, but when i tried ...
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1answer
26 views

Create elevation dependent mean values in ArcGIS RasterCalculator

I have two rasters. Raster1 is a reclassified raster for certain elevation value ranges. Raster2 is an elevation raster too but with gaps. I want to fill the gaps of Raster2 by the median of the ...
2
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1answer
104 views

Raster Calculator syntax

I have two rasters depicting climate in two periods and I want to compare their values. I want to create a third raster returning: Values of raster 1 are within the minimum and maximum values of ...
2
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1answer
25 views

How to calculate values in a 3*3 matrix using raster calculator?

How to manipulate a raster values in a 3 X 3 matrix.. using raster calculator or any other method e.g. to find out how many cells are there in a 3 X 3 matrix having cell values less than the center ...
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1answer
112 views

ArcMap 10; Syntax for Minimum operator in raster calculator

I want to linear stretch my raster grid formate having column/rows 3128, 3503 with 30 meter resolution by using the following syntax in raster calculator of arcmap 10.1. ("raster" - ...
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66 views

Normalize the NDVI raster 0-255

NDVI values raster computed by using the band 3 and band 4 reflectance values b4-b3/b4+b3. The output raster is of 32bit type formate although the possible ranges that shows in statistics parameter ...
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106 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 ...
3
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2answers
75 views

How do I get rid of this thin band between raster layers created from TNM?

After hitting my head against the table for many days, I'm humbly presenting myself to the QGIS community. I downloaded 4 IMG files (1/3 arc second, elevation data) from The National Map on the USGS ...
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2answers
153 views

QGIS's raster calculator— running as a batch process?

I have a series of raster files (150 or so) that I need to multiply by a baseline raster. Unfortunately, the series of rasters have a different cell size (30mx30m aka .00027777778 degrees x ...
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80 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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0answers
48 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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1answer
85 views

Why does the composite raster pixel values not cover the full range of RGB and what does this mean for reclassification after conversion to int?

I have about 30 or so composite rasters in IMG format that I need to 1.) Preserve the date that the raster was created and 2.) Combine all of them. My workflow is: Step 1: raster calculator, ...
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1answer
39 views

Multiply raster by Numpy derived float value

So I have a python script that uses numpy to calculate the mean of a field, then I try to use that mean value in a raster multiplication as follows: na = ...
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131 views

Focal Statistics for Special Neighborhood

I'm looking to calculate focal statistics for each cell of a raster, within a neighborhood of a specified criteria. Background - I have three binary rasters, each representing a single vegetation ...
4
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1answer
171 views

Raster Calculator making incorrect calculations in ArcGIS for Desktop?

I am trying to use raster calculator (ArcMap 10.2.2.3552) to apply a poisson generalized linear model to estimate species abundances based on elevation. The outputs don't make any sense to me, and I'm ...
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1answer
45 views

Adding rule to raster calculator?

IF there are one or two urban cells in the Moore neighbourhood AND there is a road running through this cell. How do I add this rule in my raster calculater?
3
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1answer
38 views

Fast editing in raster calculator — adding lots of images together

I need to add pictures together to make one raster. In one session there are about 150 - 200 images (named randomly - see syntax example) There are about 50 sessions (named randomly) Is there any ...