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

learn more… | top users | synonyms

3
votes
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 ...
0
votes
1answer
60 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 ...
0
votes
0answers
12 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 ...
0
votes
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 ...
0
votes
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....
0
votes
0answers
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 ...
0
votes
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 ...
0
votes
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 ...
2
votes
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 ...
1
vote
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....
1
vote
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 ...
1
vote
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
votes
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 ...
2
votes
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
votes
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 ...
0
votes
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 ...
2
votes
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-...
1
vote
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 ...
1
vote
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 ...
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
votes
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 ...
1
vote
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
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 ...
4
votes
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 ...
2
votes
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!...
1
vote
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
votes
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 ...
3
votes
1answer
44 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 ...
3
votes
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 ...
1
vote
0answers
20 views

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") - (...
1
vote
1answer
27 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) & (...
1
vote
1answer
60 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 ...
0
votes
2answers
52 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 "...
1
vote
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 ...
1
vote
1answer
74 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 ...
3
votes
0answers
57 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 ...
1
vote
1answer
76 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. ...
1
vote
2answers
33 views

Recalculating raster based in number of cells?

I am working with binary rasters of fish species distributions (1=presence, 2=absence). I am looking to recalculate each raster in this way: Count the number of cells with value 1. Divide: 1/Number ...
0
votes
0answers
40 views

Create Cost Surface Raster with slope as percentage of total costs

I know there is a similar question on this website (How to Create Cost Surface Raster for Least Cost Path Analysis?) , but I couldn't find the answer that I'm looking for. I'm currently working with ...
2
votes
1answer
64 views

Is QGIS Raster calculator faulty?

I am trying to perform some rounding operations on rasters. I have used GDAL to convert the raster to an integer which is fine but now I want to /100 which should be simple in raster calculator but ...
1
vote
1answer
108 views

Conditional statement in raster calculator - ArcMap

I'm Just wondering how to incorporate a conditional statement basically to say: if value in raster >= 128, then put in new raster, otherwise make the values null. Basically the purpose of this is ...
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 ...
0
votes
1answer
39 views

raster calculator fail to sum?

I am having a question about the raster calculation as I am trying to create a tool which I want to link with my python script to sum weight rasters but if failed to do so. here is my code: #*the ...
4
votes
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 ...
1
vote
1answer
64 views

Calculating maximum value in Raster Calculator of ArcGIS for Desktop?

I have MODIS NDVI data of four months and I have to calculate NDVImax. I am using the Raster Calculator of ArcGIS and have been using various algorithms like [MAX ("june2000", "july2000" , "...
3
votes
1answer
29 views

In ArcGIS raster calculator can you access the individual cells surrounding a central cell like you can in GRASS r.mapcalc

Is there a way to do the following in Raster Calculator in ArcGIS? In GRASS r.mapcalc you can access the cells surrounding the current cell by writing inputRaster[a,b] where a and b represent the ...
0
votes
1answer
81 views

Meaning of ERROR 000539: Error running expression: rcexec() <type 'exceptions.ImportError'>: No module named os?

In Raster Calculator using: (FocalSt_meanDEMtif5-FocalSt_minDEMtif1) / (FocalSt_maxDEMtif2-FocalSt_minDEMtif1) What is the meaning of ERROR 000539: Error running expression: rcexec() : No ...