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

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1answer
644 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
40 views

calculating first quarter of a raster by zonal statistics

I want to calculate the 1th quarter of raster values (beneath polygons) by zonal statistics but it does not have quarter. Zonal statistics has :MIN, MAX, MEAN, MAJORITY,RANGE,.... and does not have ...
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1answer
61 views

Drawing concentric circles that correspond to free space loss formula?

I want to be able to draw a circle with 50km radius and then fill the circle with values corresponding to the free space loss formula below: FSPL(db)=20 log10(d)+20log10(f)+32.44 for example: a ...
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0answers
68 views

Arcpy code only works when run in two chunks, not as one piece

I have a weird thing happening with my script. When I copy/paste it into the python cmd line within ArcMap, I get error messages. However, if I run the first part, then copy in the very last line by ...
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1answer
37 views

Mathematical functions in Arcmap's raster calculator - Derivatives & Complex numbers

Is it possible to calculate derivatives and complex numbers on rasters inside the raster calculator in Arcmap ? If not, is there any walkaround ? Also, QGIS or any other opensource software can ...
3
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1answer
35 views

Changing climate grid values by adding decimal point numbers

I have climate grids (based on climate data from 1961-1991) which I have converted from ascii to raster in ArcGis 10.2.2. The temperature is in degrees celsius. I want to alter the temperature values ...
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13 views

Rescale raster files in QGIS

I want to construct a surface of predictions in QGIS, using several probabilities I otained previously in R, by constructing GLMM. But I rescaled my variables before constructing GLMM, so I also need ...
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1answer
296 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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0answers
9 views

Write correct BandDescriptor expression - calculate the difference between bands in two geospatial products from Python

I need to calculate the difference of the bands stored in two files saved in the NetCDF. Both products used in the calculations describes exactly the same area, i need just the difference between them....
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21 views

Executing Power Equations in Raster Calculator?

I am attempting to conduct a calculation in raster calculator, however I am coming up with numbers that I know are incorrect. The equation I am attempting to execute is as follows: 84.146e-.00006x ...
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2answers
360 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
907 views

How to convert float raster to integer raster?

I am using Normalize difference vegetation index (NDVI) derived from the landsat satellite band 3 and band 4 that have float values ranges from -1.0 to 1.0. I want to see the attribute table that is ...
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1answer
34 views

Inputing Temperatures

I am attempting to impute temperature based on elevation in ArcMap 10.2, using a regression equation. So far, I have been unsuccessful, as my output raster from my regression equation has the high too ...
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0answers
12 views

How to convert time variant data within netcdf file?

I'm developing a webapplication and i want to include different global climate raster datasets with temperature and precipitation values. I have found a good temperature dataset, but unfortunately the ...
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1answer
86 views

Edit raster classification manually using polygons in 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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2answers
35 views

ArcMap raster calculator raising negative values to a power

I have a raster calculator expression: Power("dataset.tif",1.5) where dataset is float, and has some negative values. When I run this expression in raster calculator, all of the negative values ...
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1answer
168 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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2answers
3k views

Raster Calculator Workaround in Arcpy for Suitabiliy Analysis

This is my first attempt at a complex stand alone python code. I am self teaching the arcpy module, well at least attempting to. I am having a great deal of difficulty getting my site suitability ...
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0answers
21 views

Extracting pixels with value in one raster but NoData in other raster?

I have two raster A and B, and they are representing the info for Florida. Ideally A and B should have same coverage. However, due to some data processing issue, B's boundary is a bit smaller than A's....
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0answers
27 views

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
38 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 ...
2
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2answers
48 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
344 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 ...
1
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1answer
115 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 ...
2
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1answer
28 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
25 views

SAGA Raster Calculator in QGIS Graphical Modeller not subtracting [closed]

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
28 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
226 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
2
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1answer
42 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-...
5
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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 ...
4
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2answers
135 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 ...
2
votes
1answer
53 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 ...
1
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1answer
74 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
194 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....
1
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1answer
36 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
votes
1answer
910 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
votes
1answer
29 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 ...
0
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0answers
13 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
votes
2answers
93 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
votes
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 ...
4
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5answers
155 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 ...
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
44 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.
1
vote
1answer
64 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
votes
2answers
115 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
votes
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 ...
2
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1answer
49 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!...