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

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1answer
44 views

script to draw a square where the raster pixels contained within are a certain type and greater than X

I have a raster containing different pixel values and I am interested in having squares drawn around areas that are at least X m^2 and containing at least Y type of pixels. The data looks like this, ...
2
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0answers
364 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 ...
1
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1answer
151 views

Trouble using gdal utilities in python (no output files created)

I am trying to use gdal utilities like gdal_polygonize in python to polygonize my raster image but I'm having trouble understanding the commands. What I mean is in some places the command is of the ...
0
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0answers
32 views

QGIS 2.6 Raster Calculator output is smaller than expected

I have used Raster Calculator to merge several raster layers. The layers were all created using geographical features in the same transect, but as the features are not evenly spread, the raster layers ...
1
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0answers
74 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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0answers
60 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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3answers
95 views

Make all pixel in raster have the same value

I have a raster file with two categories: category 12 (total count=350) and category 14 (total county = 500). The attribute table looks like this: rowid Value Count 0 12 350 1 14 ...
2
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2answers
261 views

NDVI from Landsat8 LandsatLook images

I have downloaded landsat image from this site and now Im wondering if i can get NDVI index from it. In raster calculator I have only 3 ranges, shouldnt be four? Or am I doing something wrong......
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1answer
34 views

Mod function in GRASS GIS

What is the equal of ArcGIS Raster calculator "Mod" function (Finds the remainder of the first raster when divided by the second raster on a cell-by-cell basis.) in r. mapcalc in GRASS GIS?
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0answers
97 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 ...
4
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1answer
324 views

How to compute NDSI in ArcGIS for Desktop?

How do I compute a Normalized Difference Snow Index (NDSI) in ArcGIS's Raster Calculator? I have a Landsat 8 scene (hdf4 format) that contains derived surface reflectance band-by-band. Each band is a ...
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0answers
99 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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0answers
148 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 ...
0
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2answers
310 views

To select the range of values using Raster calculator in QGIS

I am working on a project where, I need to give ratings for the range of values. I have the following ratings index ratings 0 to 4 4 5 to 8 3 9 to 11 2 12 to 15 1 I am ...
1
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0answers
279 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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0answers
61 views

Calculating where the Z values of two rasters intersect

I have several raster layers which are depth horizons, one of these horizons cross cuts the others and I would like to calculate the line along which this occurs. i.e. the line along which the Z value ...
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0answers
39 views

Automating Raster Calculator [duplicate]

I am seeing mixed answers on other posts so I thought I would ask here. Is there a way to automate the raster calculator? I am trying to create a series of inundation maps at fine increments. It ...
0
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2answers
94 views

Syntax Raster Calculator

I have never worked with the raster calculator before and I can't solve my problem. There are two raster datasets. One contains roads ( "closed", "in use", "under construction") and the other dataset ...
4
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1answer
119 views

Does gdal_calc only support 26 input raster files at a time?

In gdal_calc.py, input files are specified with letters A-Z. Here are two files, input.tif and input2.tif, being averaged into result.tif: gdal_calc.py -A input.tif -B input2.tif --outfile=result....
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0answers
130 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 ...
3
votes
1answer
140 views

How to center continuous raster layer by subtracting mean and dividing by standard deviation using QGIS raster calculator?

I'm trying to extrapolate a spatial model to a map in QGIS using the raster calculator. The model predicts the value of a pixel given the environmental conditions at this location (e.g. elevation, ...
3
votes
1answer
166 views

How to use the con statement in raster calculator to include a raster as a condition in an existing raster

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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0answers
172 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 ...
0
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1answer
158 views

ArcGIS Raster Calculator wont work in main model

I've created a Submodel in ArcGIS, which stretches my rasterdata to new values. The strange thing is, that the model works, if I run it itself - as soon as i implement it in the main model, I get ...
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0answers
146 views

How to set floating point raster values to NoData when raster does not have valid statistics

I have a raster with some values of 99999 that I want to set to NoData in Arc 10.2.2. I've tried using the SetNull dialogue box, the SetNull arcpy function, and the Raster Calculator dialogue box as ...
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0answers
391 views

Raster Calculator Addition - missing output. ArcMap 10.2.2

I'm currently undertaking multi-criteria analysis and have 5 raster inputs which I would like to add. I have done this before on a previous project with no issues. When I add the 5 layers, only 4 are ...
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2answers
56 views

gdal_calc : fails with value 0?

I working to invert values of a one-band tif files (download sample). If i use 254 it works: $ gdal_calc.py -A ./shadedrelief.tmp.tif --outfile=whited.tmp.tif --calc="254*(A>180)" 0 .. 10 .. ...
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0answers
54 views

How to extract the raster files from .prj?

I am interested in using Raster Calculator tool for which i need the desired raster files. But i came across a problem i.e. when i converted my vector files to raster and saved them they were saved ...
0
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1answer
38 views

Use of OTB BandmathX

I have a couple of three-band satellite images that I want to apply an expression to and get a three-band output. The expression is of a simple form: output_pixel= (input_pixel*d^2)/cos e After ...
1
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1answer
81 views

Python error in Con function

I am trying to add two different rasters using the Con function. I am iterating the raster layer using the for loop to obtain two rasters belonging to the same species and their formats are in grid ...
2
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1answer
294 views

How to use the math tool (“times”) in ArcGIS modelbuilder to multiply two raster sets while using an iterator?

I have two sets of rasters (in the same gdb), representing "loss" and "forestmask". I would like to multiply each forestmask raster (value 1 = forest) with its corresponding loss raster (value 1=...
2
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2answers
162 views

Combine multiple binary rasters to a single raster

I have 5 different species richness maps which I am trying to join in order to show one cohesive map. Each species raster layer has values of 1 and 0; 1 if the species lives there and 0 if the species ...
2
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0answers
55 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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0answers
123 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 ...
0
votes
1answer
736 views

Fixing Raster Calculator Error 000539 ImportError: No module named numpy? [duplicate]

I've created 4 hillshades for a particular area to represent the 4 seasons in a year. The equation I now need to use to determine solar insulation is 1000*hillshade/255 in raster calculator. However, ...
1
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1answer
273 views

I want to compare multiple raster layers against each other to identify changes in pixel values over time

I am using LAI values to assess vegetation growth over large areas. I want to be able to identify areas that are doing well and areas that are decreasing based on the changes in pixel values. Ideally ...
0
votes
1answer
486 views

ArcGIS Raster Calculator error 000539 ImportError: No module named numpy?

I am running ArcGIS 10.2.1 on Win7 64bit. I have finished doing an NDVI, and after defining a vegetation presence threshold at 0.05, opened the Raster Calculator (via Map Algebra in the Arc Toolbox) ...
0
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1answer
253 views

Conditional calculation - QGIS Raster Calculator or GRASS r.mapcalculator

Is it possible in QGIS either directly or via plugins to do a raster calculation including an if statement? e.g., if raster1 > 0.3, then raster 1 * raster 2, else raster1 x raster3...something like ...
0
votes
1answer
118 views

QGIS raster calculator wrong output

I am trying to create a mask from a DEM (SRTM tile) using raster calculator in QGIS. I have performed the same operation in ver 2.6 with no problem but in the current version the output is incorrect. ...
2
votes
2answers
196 views

Raster calculator - addition

Help!!! What am I doing wrong? I have generated two rasters from vector layers. They cover the same extent and have the same projection (Irish Transverse Mercator) and cell size (5m x 5m). I have '...
0
votes
2answers
95 views

Computing View Distance in One Direction from Point on Elevation Raster in PostGIS?

I'm a software developer just getting into GIS, so please forgive me if I don't use proper lingo, or if I use proper lingo incorrectly! I have a raster of elevation data. For a given point in the ...
0
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0answers
117 views

apply gdal to calculate raster that is already in qgis raster calculator

I am using the following code in qgis to calculate some raster.It is not giving the correct result as it is in arcpy.I want to apply same in gdal.Can anyone help me how to use the gdal api.Please give ...
0
votes
1answer
32 views

Implementing GLMMs in ArcGIS

I am looking to create a predictive model in ArcGIS. I have done this previously with glm with poisson distribution and found it relatively straightforward in raster calculator e.g. exp(intercept + (...
2
votes
1answer
29 views

Combining several raster files generated from polylines

Maybe I'm just missing the point somewhere... I'm working on a path distance analysis, specifiying the cost layer. For this I have built a model, where I have roads and trails, both polylines, that I ...
0
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2answers
488 views

Combine overlapping rasters and include cells with no data

I'd like to combine about a dozen rasters into one raster that contains the "summed" cell values where overlaps occur. In doing so, I need to be able to retain cells that either have no data, or that ...
1
vote
1answer
263 views

Qgis raster calculator not giving output

I want to calculate some result using QgisRasterCalculator and using the code mentioned below.Problem is i am not getting any output raster also if i use this formula in raster calculator it gives nan....
2
votes
1answer
2k views

ArcGIS Raster Calculator fails with Error 000539

I have been using Raster Calculator in ArcMap 10.2, today it started returning error 000539 for all actions. Previously it had worked fine. I have not made any change ot my ArcGIS, Python, or Windows ...
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votes
1answer
333 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 ...
1
vote
1answer
640 views

QGIS SAGA Raster Calculator [closed]

I am using SAGA --> Grid Calculus --> Raster Calculator on QGIS version 2.6. The formula I am using is: ifelse(gt(a,0), (a), b) where a is my layer with values in a greater extent than that of b. ...
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0answers
232 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 ...