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

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266 views

Cause of ArcGIS Raster Calculator Parsing error <type 'exceptions.SyntaxError'>: invalid syntax?

This is my first attempt at much code in the raster calculator of ArcMap 10.0, but I think I'm close. I have nine rasters (A-I below) and want a new raster with value = 1 where any of the rasters ...
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42 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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357 views

Raster vs. Raster Scatter Plot in ArcGIS

I created two raster datasets from the same world view 2 image. One dataset is NDVI, the other is a normalized surface water index (NDSWI). I would like to create a scatter plot for a pixel by pixel ...
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1answer
424 views

Getting Error 000539 from Raster Calculator?

I am new to Arc and 10.2 but can not seem to figure out why this won't work. Executing: RasterCalculator Con(("SLOPE_SLO.tif" >= .015) & ("SLOPE_SLO.tif" <= .15,1,0)) ...
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28 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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2answers
58 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 ...
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37 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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1k views

Conditional Statements in QGIS raster calculator?

What is the equivalent statement of the following expression in the QGIS raster calculator? Con(((Abs("DEM" - "FSMin") > 120) | (Abs("DEM" - "FSMax") > 120)), 1, 0) I have no problem ...
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24 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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1answer
202 views

Issues calculating range with QGIS 2.0 raster calculator

I would like to calculate a simple range using the QGIS 2.0 Raster Calculator, but am getting strange results. I believe I am not using the correct syntax. To get all values between .003-.5, I ...
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388 views

Calculating 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 ...
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34 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
21 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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2answers
1k views

Querying raster in ArcGIS Desktop?

I am using ArcGIS 10 (includes spatial and geostatistical analyst). I have a raster (GRID) with a value range of -167 to 18. I would like to query the raster and create a new one with only the ...
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39 views

What Raster Calculator expression to use? Need to Set Nodata to the overlapping pixels of two rasters (w data example)

Colleagues, hello! For quite a while I`m struggling to make up a map algebra expression in the ArcGIS Raster Calc… On the output I need a single raster with values 0, 30 and nodata (-128). The ...
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1answer
32 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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1answer
27 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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27 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
45 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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28 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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1answer
26 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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18 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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24 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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595 views

Calculating Topographic Exposure with Raster Calculator

I need you help trying to calculate Topographic Exposure (TOPEX) on a DEM in ArcGIS. I am trying to figure out wind exposure on a DEM with 25m cells. There is a great blog post where someone explains ...
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183 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
56 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 ...
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1answer
35 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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1answer
54 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 ...
3
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2answers
657 views

Scale raster in ArcGIS using raster calculator

I have a raster with values ranging from 0 to 8991130624. This raster is actually the result of a cost distance analysis. I want to scale the raster to range from 0 to 1 and take the inverse? so ...
2
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1answer
240 views

How to iterate GRASS region definition?

I am using GRASS r.skyview command (v.7, Windows) to determine "urban canyon effect" on pollution due to the presence of buildings. The command nicely works, unfortunately I need to process a very ...
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52 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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22 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
39 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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40 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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2answers
544 views

Why does Raster Calculator return GRID ERROR-Unable to open input grid?

I'm calculating Simple Ratio (SR) from NDVI using Raster calculator in Arcgis. Here is expression I wrote in Raster calculator. SR=(1+float[NDVI_apr.tif])/(1-float[NDVI_apr.tif]) But when I ...
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1answer
203 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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2answers
111 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
189 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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3answers
40 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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84 views

Trouble with reading Leaf area index (LAI) Modis on QGIS

I am having trouble reading my Modis LAI data on QGIS. I imported my Modis hdf files and I used the QGIS raster calculator to apply the scale factor and all I get is a blank gray tile. My goal is to ...
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1answer
24 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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36 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 ...
3
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0answers
64 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 ...
3
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1answer
673 views

Help with scripts for processing raster files with the raster calculator in QGIS

I am trying to process some raster files using python scripts in Qgis 2.20, and I have been having trouble finding any documentation on using raster calculator in scripts being run in the processing ...
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36 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 ...
2
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1answer
628 views

Managing sizes of input rasters for raster calculation in ArcGIS Desktop?

To calculate any formula (conditional statements/relational operation etc) in the raster calculator in ArcGIS using two different sources of raster images, I'd like to know input rasters must be the ...
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46 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 ...
2
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1answer
595 views

How to separate raster bands in ModelBuilder?

I have a simple model that iterates through folders to collect imagery, mosaics them and clips the mosaic to a study area boundary. I need to produce an NDVI from the clipped 4-band mosaic ...
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0answers
51 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
57 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 ...