# Questions tagged [raster-calculator]

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

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### 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", "outputfile....
1k views

### Number inputs as raster calculator variables in QGIS Modeler

How can i use input numbers as variables in any of the raster calculator algorithms in QGIS through the modeler? One very simple example of that would be a model that allows me to divide raster cell ...
5k views

### Why does Raster Calculator (RasterCalculator_sa) give ERROR 000539 in ArcPy?

I am getting a not executed error for a raster calculator. Here is part of the output: File "C:\projectTemp\FloodAnalysis\floodxsectionanalysis.py", line 107, in makeSeemless arcpy....
6k 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') arcpy.env.workspace=r'F:\Sheyenne\...
10k views

### Normalizing raster using raster calculator in ArcGIS 10.3.1? [duplicate]

I have been trying to 'range standardise' or normalise my raster values from 0-100 and I know how to do this mathematically: ("raster"-min("raster"))/(max("raster")-min("raster"))*100 and I have ...
9k views

### QGIS Raster Calculater Syntax

I am trying to use the raster calculator in QGIS to combine a number of rasters. I want to calculate a mean, this is easy: (raster_1@1 + raster_2@1 + raster_3@1) / 3 I then want to create a max. ...
2k views

### How to reclassify in Rastercalc?

I now need to reclassify, I'm using rastercalc... but I can't get the syntax right!! I need that values >0 become 1 I found this example... eq( [relief]@1, [mask]@4, 150 ) so I tried: ( [raster A ...
10k views

### Can Compound Topographic Index (CTI) / Topographic Wetness Index (TWI) produce negative values?

I am calculating Topographic Wetness Index for a study area using SRTM DEM (90 and 30m). I've seen several versions of TWI (CTI). I have been using: TWI = ln(As +1 / tanB) where As = ...
618 views

### Upslope and downslope distance or area using ArcGIS Desktop?

Is there a possibility to determine the surface area above the road and the surface of the terrain below the road or between two or more roads? I want to pull the trees down the hill and up the hill ...
1k 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 ...
5k views

### Deleting values from raster file using ArcGIS Raster Calculator?

I have a raster that denotes certain landcover types. How do I delete all of the pixels except for the ones I want? I tried going through the symbology tab and while that deletes it for display it ...
1k 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 "...
204 views

### Standardising DEM raster for a MCE

I'm trying to complete a Multi-Criteria Evaluation for an MSc assessment and am in the process of standardising my factor maps. Unfortunately, my DEM layer (ASCII file) keeps changing from this: To ...
11k views

### How to standardize raster output from 0 to 100 using raster algebra?

I am working on generating an integrated moisture index based on the following equation: IMI = (hill shade * 0.5) + (curvature * 0.15) + (flow accumulation * 0.35) Iverson et al. 1997 Another ...
37k views

### Cropping raster layer using QGIS?

How do I crop a raster layer in QGIS? I want to make contours from a section of a layer, and including the whole layer will create far more data than I need and slow down the rendering. I have ...
5k 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 ...
3k views

### Change NODATA pixel value in raster to arbitrary value

I want to change the value in all pixels that are currently 0 to 800 in QGIS 2.6.1. 0 is listed as the no-data value in Properties > Transparency. I have unchecked the No Data Value box there. Then I ...
463 views

### Automating creation of toe of slope from DEM using ArcGIS for Desktop?

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 ...
9k 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 ...
6k views

### Specify a field in attribute table with raster calculator

How can I specify the attribute field to use in the raster calculator of ArcMap 10.2? In 9.x, I used the dot notation. i.e. To use the "New_Value" field, I could do the following: [MyRaster]....
12k views

### How to use OR in a CON statement, in the ArcGIS Raster Calculator?

I'm trying to compare two rasters, and create an output based on a formula like: if raster1 > 10 or raster2 < 20 then raster3 = 30 How can I specify the OR in the raster calculator's CON ...
8k views

### Extending size (area) of raster using ArcGIS Desktop

My problem is that I would like to multiply two rasters using raster calculation tool. Both rasters have values 0 and 1, but the covered area of first raster is bigger (100 x 100 miles) then the area ...
615 views

### How to update raster pixel values based on another raster with conditions in QGIS?

I have 2 land cover rasters. I want to update parts of the first raster with values from the second using QGIS. The workflow should be like this: 1. Select values equal to 30 and 34 in the first ...
2k 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 ...
10k views

### Averaging set of rasters using Raster Calculator of ArcGIS Desktop?

How do I average a set of rasters? I have remotely sensed chlorophyll a rasters for several days and I need to get an average of the days represented as one raster layer. I am using ArcMap 9.2.
3k views

### Replacing raster values in one raster with another raster in QGIS … how to?

I have a raster (DEM) and want to replace a few cell's values with the values from another raster in QGIS. I would have done this with the "over" tool in the raster calculator in ArcGIS. Specifics: ...
182 views

### Averaging large number of raster layers using ArcGIS for Desktop?

I have a large number of rasters (300+) I would like to average using Raster Calculator as is explained at Averaging set of rasters using Raster Calculator of ArcGIS Desktop? I know I can manually ...
3k views

### Create an X,Y latitude and longitude grid from an raster

I have a satellite image (LandSat 5), I want create a raster with X,Y coordinates, this is possible in Model Builder of ArcGis 10.0? or other option. I know that the option \$\$YMAP (\$\$XMAP) not work ...
2k 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)) D:\GEOG_480\Final2\...
695 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....
1k 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) ...
499 views

### How to prevent RGB composite flatten to 1 band after raster calculation

I have a series of landsat wanting to process in raster calculator, but after doing the tool it happened these output images only contain one single band. They used to be RGB 3-band images. It is on ...
756 views

### Normalizing raster using raster calculator raises TypeError

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 ...
3k views

### 30,000 data points… can this be reasonably served using openlayers?

I'm trying to tackle a web GIS problem and need to figure out the best strategy. I have a map with 30,000 cells on it forming a grid for the province of Alberta. I have a list of data points for ...
7k views

### Normalize raster values to 0-255

I need to normalize the values attained from a band ratio to 0-255. I'm using QGIS. How do I do this? Any ideas?
6k 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 ...
4k 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 ...
605 views

### Combining Geological Grids and extruding between them?

I have a situation where I have 3 Geological grids, each showing a different horizon + the Seabed Grid. I need to extrude between these grids in order to make the 3D polygon for the geological ...
2k 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 ...
5k views

### Using individual bands from multi-band image in ArcGIS raster calculator?

I'm trying to use individual bands from a multi-band TM image (IMG file) within the raster calculator in ArcGIS 10 (SP2/3). I can add individual bands to my MXD, but raster calculator will only use ...
1k views

### How can I change the class of one pixel in a classified image?

I have a classified image (I did it in ERDAS) with six categories. There are some misclassified pixels (especially high-density urban category). Is there any way that I can choose one pixel and then ...
215 views

### Raster calculator reclass 0 as 0 QGIS

I want to process a raster with values 0-16. I want to set all values between 1 and 15 as 1, a value of 16 as 0 and cells with a value of 0 as 0. How do I maintain a cell value of 0? I have tried ...
2k 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 ...
2k views

### Rounding raster values in QGIS raster calculator?

Is it possible to round raster value in QGIS to a given number of digits? I have raster data with temperatures as values but the authors have made the values Celsius * 10. That is, a temperature of 2....
2k views

### Summing pixel values from several raster layers with partial overlap in QGIS?

I have several presence maps (rasters values 1 and 0) from different species. They are all from South America, but they do not have the same extend (i.e., different sizes). So, I am trying to ...
2k 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 ...
10k views

### Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?
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### How to reclassify raster inside polygon mask, leaving values outside as they are?

I am in the final stages of a landcover classification and need to reclassify thematic raster values that are inside different polygon masks, while leaving the values outside as they are. Can I do ...