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

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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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1answer
340 views

Raster Calculator in QGIS returning 'nan' values

I am attempting to add two rasters using the QGIS raster calculator and every output ends up as 'nan'. There were no problems with the raster calculator before trying to add these rasters, so I am ...
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3answers
117 views

Raster calculator : How to make 0 + NoData = 0?

I have a point data layer (vector) that I converted to a raster layer. I want to replace the NoData value (between each raster point) in the point raster layer by 0. So, I made a background raster ...
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1answer
146 views

DEM Processing in ArcMap

I have a question regarding DEM. I have downloaded SRTM DEM 30 m and I did a mosaic for the data using Mosaic tools in Arcmap to a Mosaic to a new raster. However, I got a DEM raster with values of ...
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72 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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1answer
67 views

Iterate - Raster Calculator - 8 Day MODIS LST to Monthly Avg

I have 8-day MODIS Land Surface Temperature data from 2009-2013. I have used Model Builder to extract the LST_day and LST_Night Subdatasets (in different model runs). What I am attempting to do next ...
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1answer
57 views

Adding multiple rasters produces unexpected results. I have set the data extent to the same in all rasters

I am trying to add three rasters together. I'm trying to figure out where I am going wrong so I am going to list out what I am doing: I have Raster_1, Raster_2 and Raster_3. Raster_1 and Raster_2 ...
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1answer
46 views

How to combine bands from different rasters using the global mapper raster calculator?

I am wondering how to specify what raster you are getting the band from in the global mapper raster calculator? When you open it with a more then one raster open you can check the boxes to define ...
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3answers
74 views

Making raster output based on comparison between 2 input rasters using ArcGIS for Desktop?

I have 2 input rasters of rainfall for summer/winter and I want to make a 3rd output based on which one has the max value for that cell. So if the max value at the cell is summer it will assign 1, or ...
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3answers
212 views

Adding two raster datasets that overlap while maintaining extent of larger raster dataset?

I am using ArcMAP 10.0 How do I add two raster datasets that overlap while maintaining the extent of the larger raster dataset. I have thought of adding zero values to the smaller raster to then be ...
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94 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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1answer
57 views

Parsing error : invalid syntax (line 1) from ArcGIS Raster Calculator?

I have a (Aspect)raster (32bit, floating point,overall 2.9GB) of a landscape and need to devide it with π/180, in order to get the mean aspect later. My raster calculator (Spatial Analyst --> Map ...
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95 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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2answers
55 views

How can I stop my map algebra being limited to the size of my smallest raster?

I have five input rasters and I'm using map algebra to find areas where all of them have a value over 75, areas where all of them are over 25, and areas where one or more are under 25. I can do this ...
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1answer
269 views

Using Loop with Raster Calculator in ArcPy?

I am trying to loop through multiple rasters and extract cells that are above 0.1 The code I am trying to use is: import arcpy arcpy.CheckOutExtension('Spatial') ...
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1answer
95 views

How can I add a Raster Calculator tool on QGIS Processing Modeler?

I'm trying to add the Raster Calculator to a model I'm creating using the Processing Modeler of QGIS 2.6 Brighton. It does not allow me to add the normal Raster Calculator tool under Raster, so I ...
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1answer
325 views

Raster Calculator Iteration in ModelBuilder?

I have a large number of rasters and I want to add 1 to each of them (e.g. each raster's values currently range from 0 to 1, and I want to make them range from 1 to 2). I believe ModelBuilder, using ...
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1answer
48 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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1answer
114 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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59 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. ...
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1answer
50 views

count band numbers from multiband raster image

My raster image has 10 bands (10 bands are 10 year), cell values of each one are 1, 2, 3. One is negative anomaly, 2 is no change area, 3 is positive anomaly. Now I want to find how many years out of ...
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46 views

how I can get raster calculator select files with similar names?

The idea is to select raster files with parts of similar name, for example: Filenames (in between many others raster with other names, but in the same folder): 28feb11evs 28feb11evv 28feb11pr ...
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1answer
73 views

How do I input this function to “Raster Calculator” in Model Builder , in ArcGIS 10.2? [closed]

The raster files that function refers are as follows: Precipitation (o “Raster” in figure 1): Variable CN_2S_7ma: Constant CN_8S_7ma: Constant The mathematical function that must be entered is as ...
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1answer
549 views

Using Raster Calculator expression in Python

I've posted about this problem before but I've got a few new questions. So here's the problem. I have two rasters containing bathymetry data: one containing the bathymetry of the sea floor, we'll ...
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151 views

Expressing a Raster Calculator expression with Math Toolset

So here's the problem. I have two rasters containing bathymetry data: one containing the bathymetry of the sea floor, we'll call this raster1, and another containing the difference between two ...
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1answer
70 views

QGIS Treat null as zero in raster calculator

In QGIS - I have an irregularly shaped raster - I wish to clip an irregular area out of it (call it raster A) with that area set to null. I masked the area (vector polygon) I want to remove and used ...
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1answer
444 views

Multiple CON Expression in ArcGIS Raster Calculator

How can I write the following conditional statement with CON? If ((VALUE = 20 OR IF VALUE=24) then assign value 0, else 1) Con(("Raster1", 0, 1, "VALUE =20")|("Raster1", 0, 1, "VALUE =24"),0,1) I ...
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1answer
85 views

TypeError raster object is not iterable when trying to normalize DEM

In ArcGIS 10.1 I'm trying to normalize a section of a DEM (digital elevation model) from original values to values ranging from 0 to 100. First I clipped the raster DEM with an irregulary shaped ...
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86 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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1answer
118 views

Reclassify in QGIS using Raster Calculator?

I have downloaded data from the USGS to create a Map for a malaria risk in east africa but my question is only about the actuall Input in the Raster Calculator. I have a RFE Tiff that shows the ...
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1answer
69 views

Edit raster classification manually using polygons - ArcMap

I want to edit the elevation/z values of certain zones on a raster in ArcMap. I followed this example by creating a polygon, assigning a value of 7.5, then converting the polygon to a raster, finally ...
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1answer
57 views

Multiply a stack of floating point rasters( composite raster ) with a constant

I am trying to multiply a floating point stack of rasters (10 layers) with a constant and round up to the next integer. I have the formula RoundUp(10*composite_raster) in raster calculator, but for ...
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29 views

Problem with making raster from Aspect and wind direction data [duplicate]

I know its not correct to ask for work flow, but I am learning by doing and now I don't know how to move on. I'm trying to make new raster which will represent the facing sides of hill around a ...
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44 views

Spatial segregation from a raster of racial distribution in the USA

I am trying to measure the degree of racial segregation at some geographic level (let's say the county level, for simplicity) in the USA. I have a shapefile with these geographic units. To do so, ...
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2answers
357 views

Masking out places with elevation below 5 m from a DEM

I have a DEM of a study region; I want to modify the DEM in order to reflect the coastline outlook when the sea level was 5 meters higher than today. What I have done so far is to use 'Raster ...
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1answer
43 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, ...
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269 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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1answer
124 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 ...
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28 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 ...
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0answers
67 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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57 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
77 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 ...
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2answers
219 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 ...
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1answer
33 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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88 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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1answer
261 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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87 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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206 views

Preconditions for subtracting two rasters in arcmap

I have two precipitation rasters, each with a different raster cell size 4.1 x 4.1 km, 4.6 x 4.6 km). The two rasters have the same geographic coordinate system, but different projections. I would ...
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132 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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2answers
258 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 ...