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

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Is there a Python equivalent to QGIS Raster Calculator's “file1.asc” AND “file2.asc”

I would like to script a calculation equivalent to QGIS Raster Calculator's "file1.asc" AND "file2.asc". I have 18 data raster files which I would like to do the equivalent of ADD to each of five ...
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1answer
25 views

ArcGIS raster calculator: ERROR 000539: Error running expression: rcexec() <type 'exceptions.ImportError'>: No module named collections

My raster is in the GRID format, source type is continuous and pixel type is floating point (32bit). If i use the raster calculator ("dem" *1000 or "dem >= 2m" (to highlight certain heights) it ...
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2answers
34 views

Using multiband images in ArcGIS Raster Calculator? [duplicate]

I have 5-band composite orthomosaics that I wish to apply multiple vegetation indices towards. In the raster calculator, it only displays the raster, but not the individual bands. Can someone give me ...
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2answers
330 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
104 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
24 views

Splitting multiband raster into multiple bands using ArcGIS ModelBuilder? [duplicate]

I'm using the ModelBuilder functionality in ArcGIS, and would like to take a raster that contains 4 bands, clip it with a polygon and then make NDVI from the clipped file. To do that, I need access to ...
2
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1answer
20 views

SAGA Raster Calculator in QGIS Graphical Modeller not subtracting [on hold]

I am using QGIS 2.8.1 to build a model. All is working fine until the raster calculator input. I understand that the raster calculator in QGIS Modeller is a SAGA tool. With this, I have tried both the ...
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1answer
2k 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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1answer
24 views

Removing pixels in raster map using ArcGIS for Desktop?

I made a raster. I wonder how can I remove pixels with values lesser than an specific value? for example How is possible to set the value of classes from 0.92? i have searched it and i found this ...
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2answers
219 views

How I can sum 360 raster files in a folder with the Arcgis raster calculator?

In a folder I have 360 precipitation raster files and I want to sum them all to the raster calculator
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1answer
619 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
35 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 How do I average a set of rasters? I know I can manually select each raster by double-...
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1answer
4k 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.
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2answers
1k 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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2answers
130 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 ...
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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 ...
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2answers
349 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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1answer
49 views

Why does SAGA raster calculator interpolate between cell values?

I have a raster layer with a series of integer values (classes) for each cell. I am trying to use the SAGA Raster Calculator module (called through QGIS) with conditional statements to reclassify each ...
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1answer
67 views

QGIS raster calculator: difference gives NaN for Landsat 8 scene

I'm strugling with the QGIS Raster Calculator, trying to get a NDVI image from a Landsat 8 scene (path 222, row 84, date 2015-11-15). The problem is, I'm consistently getting NaN values for all the ...
4
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1answer
185 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 (i....
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1answer
32 views

Bands disappear after Raster Calculation ArcGIS [duplicate]

I have a tif file containing 36 bands. After I applied raster calculation on the file the bands aggregate into one single band which I don't want because I need them for further calculation. People ...
3
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1answer
898 views

How to use raster calculator in ModelBuilder to batch reclassify hundreds of rasters?

I'm attempting to use iterate by raster to feed all the files through a simple map algebra expression (I'm looking at data that indicates probability of salamander habitat) so I want to reclassify the ...
2
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1answer
27 views

GRASS 7 raster map calculator

I am new to GRASS and am trying to use it because I can't afford the Spatial Analyst extension in ArcGIS. I am trying to remove all of the values in a NDVI raster less than some value to exclude ...
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0answers
12 views

Cropping out overlapping raster areas from old maps?

I am trying to take out the white bordered areas from my crop lines from multiple PDF maps I georeferenced and now exist as rasters. My goal is to mosaic or merge them all together to have a seamless ...
2
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2answers
78 views

Raster calculator in Process Toolbox Qgis

I am not able to find the Raster Calculator in my process toolbox anymore, even though I worked with the Raster Calculator through the toolbox in the same version of QGIS (2.8) one month ago. It ...
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0answers
39 views

Getting values lower than specified using Con, Raster Calculator?

Expression used in raster calculator (ArcGIS 10.2.2 for Desktop): Con(("%NDVI.tif%"> (-0.05)) & ("%Height_2015.tif%" >= 16), "%Height_2015.tif%", 0) I want an output raster containing ...
3
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2answers
3k 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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5answers
133 views

Normalizing raster using raster calculator in ArcGIS 10.3.1?

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 ...
6
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1answer
2k views

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....
3
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1answer
42 views

Using raster calculator to show multiples of particular value?

How do I use raster calculator so that the new raster only shows multiples of 128? I'm not sure what the expression should be.
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1answer
49 views

How to get the inverse of a raster in ArcMap 10.1

I have a raster ranging from 0 to 80,000. I want to invert this, such that 80000 becomes 0.0000125. When I use a raster calculator as (1/x) it returns 1s where the were values and blank where there ...
6
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2answers
107 views

How to calculate the difference between two rasters in QGIS?

I have two similar rasters of the Mount Vesuvius and surroundings: one spans 20 kilometers, and the other one 50 kilometers. The two rasters are overlapping: What I would like to do is to create a ...
6
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3answers
7k 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 ...
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1answer
44 views

How can I calculate the percent of a raster cell covered by a polygon?

First, I am going to try and intersect a raster and a polygon shapefile. I'm not 100% sure how to do this (or if I need to do this for the next step), so if you have any suggestions please let me know!...
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1answer
335 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 ...
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1answer
33 views

con statement to change the default value in ArcGIS

I have obtained a flow accumulation map using Arc Hydro tools and obtained the default value in the range of 0-204567. Now I need to change these value by default so that it gives 1 instead of zero. I ...
3
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1answer
57 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 ...
3
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1answer
31 views

Problem with algebra formulas for work with gdal_calc.py

I'm trying to update some values of a raster based on another raster. 1st raster (A): landuse data (values from 10 to 240) 2nd raster (B): mask data (only nodata values and a given value, for ...
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1answer
143 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 ...
3
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1answer
43 views

unexpected output from raster calculator function

Working in ArcMap, I am trying to convert the logit values in raster into their actual probabilities (logistic regression,) using the following function: 1/(1+Exp(-"sn_topo_poly_log")) Ive used this ...
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0answers
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problem with raster calculator syntax [closed]

I am trying to build a raster representing the output from a logistic regression model. i keep getting syntax errors. heres the script: -2.41-(15.97 * "Topographic_Predictors\wadem10m_annsolrad") - (...
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1answer
26 views

Iterate variables in Con statement in Raster Calculator- model builder

I have this formula which works fine in raster calculator on its own. Here is a simplified version of it: Con((("Trial_analysis\winter_pm" == 2)) & ("Wind_directions\winter_pm_WD" <=b) & (...
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2answers
47 views

Combining non-overlapping binary rasters with ArcGIS Raster Calculator?

The issues I keep seeing depend on unique combinations of values. I have three rocktype raster layers for area and they are edge-to-edge (they do not overlap). They each have "VALUE" fields and "...
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1answer
55 views

Constructing LS factor for RUSLE without outliers using ArcGIS for Desktop?

I'm using the following formula in RUSLE via raster calculator to obtain a LS factor Power(Flowacc)*1/22.1,.4)*Power(sin(slope)*.01745/.09,1.4)*1.4 My expected outcome is a raster from 0 to ...
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0answers
26 views

Curve Number equation

I have a floating point raster of Curve Numbers (70-91) and I'm attempting to use the curve number equation to create a weight raster for flow accumulation, to determine runoff for a single rainfall ...
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1answer
65 views

Raster calculator fails with large raster in QGIS

I'm working in QGIS 2.14.1 with a DEM ranging from 200 feet to 1600 feet elevation called "dem_3m_Zft1b" (geotiff, 16822 X 33349 cells, No-data =-9999) If I enter "dem_3m_Zft1b" > 0 in the ...
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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. ...
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1answer
424 views

PostGIS ST_MapAlgebra Assistance

I would like to perform the equivalent of the below ArcGIS raster calculator equation in PostGIS using the ST_MapAlgebra function and return it as a tif using ST_AsTIFF. Con(("Sol_gain_clipped.tif" &...
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1answer
63 views

ArcMap raster calculator error 000539

Using ArcMap 10.3, I am trying to perform map algebra on a raster with 2013 annual PRISM precipitation for the U.S. (http://prism.oregonstate.edu/recent/). The raster has 1 band an is floating point. ...
3
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50 views

Mapping habitat suitability using ArcGIS for Desktop?

I have been having somewhat of an issue recently with one of my projections. I am currently trying to map out the preferable habitat for a species in Arcgis. To do this, I performed a GLMM in R and ...