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

learn more… | top users | synonyms

2
votes
1answer
23 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 ...
-1
votes
0answers
24 views

Calculating total area overlapping raster DEM color interval whose boundaries are confined by another vector? [duplicate]

Example: I tried running raster calculator on intersections then zonal statistics checking "count" and "sum" but I get a huge table of 8000+ rows and two columns, however each cell usually have a ...
1
vote
1answer
25 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
24 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
41 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 ...
1
vote
0answers
17 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
18 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
42 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
36 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
22 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
49 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
43 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
34 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
32 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
32 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
57 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
90 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
34 views

Why does SAGA raster calculator interpolate between cell values?

I am hoping for a bit of help with a raster calculator issue that is puzzling me. I have a raster layer with a series of integer values (classes) for each cell. I am trying to use the SAGA Raster ...
0
votes
1answer
29 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 ...
3
votes
2answers
110 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
51 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
24 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
43 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 ...
1
vote
1answer
52 views

Combining information from multiple rasters into aggregate raster and populating fields accordingly

I am stuck on how to best combine the information from multiple rasters into one raster. Specifically, I am working with a time series of raster files, whereby each raster corresponds to a different ...
0
votes
0answers
27 views

Compare euclidean distance with network distance

I have a raster file with euclidean distance. It contains information about how long it takes for a chopper to arrive to certain destinations. I then have a polygon made from a service area with ...
1
vote
1answer
45 views

Calculating Geometric Mean in Raster calculator

I am calculating Geometric Mean for land degradation mapping. I am applying following formula in ArcGIS 10.2- ("GW.img" * "LULC.img" * "Rain.img" * "Temp.img" * "Wind.img" * "NDVI.img" * ...
1
vote
0answers
12 views

How it can be made a spherical cap surface with qgis raster calculator

I would like to make a test in QGIS raster calculation: I'd like to make in a flat raster surface (0m as elevation) a kind of hill or dome with the spherical cap geometry formula. P is the point ...
1
vote
1answer
21 views

Why would having a reference string “boh@10” cause a crash?

When using the raster calculator in a pyqgis script, I have several layers to process. When it gets to "boh@10", the processCalculation() call crashes. I don't see anything in the code that requires ...
3
votes
1answer
69 views

Sediment transport index STI

To calculate the STI one applies the following formula in the raster calculator: Power(“FlowAccumulationArea_Raster”/22.13,0.6) * Power(Sin(“Slope_Raster”/0.0896),1.3) Now I have a problem which I ...
1
vote
0answers
41 views

Raster Calculator and Land Change with multiple classifications

I am looking at land cover data that is separated into three classes: upland, wetland, and open water. I have the data for varying years. I am interested in seeing how the land has changed over the ...
1
vote
0answers
26 views

Do rasters have to be of same extent for the QGIS Raster Calculator?

I am trying to use the Raster Calculator but, I get a raster with Nan values. My rasters are in the same projection system but, one of them, it is a classified landsat map which covers only some part ...
0
votes
1answer
58 views

Con statement in raster calculator Arc GIS 10.3

I have four rasters (A, B, C, D) based on which my classification works. The con statement I have been using is posted below. My problem is when A_01 is 2. Area when A=2, if value of B is less than ...
0
votes
1answer
36 views

How to change value in raster layer?

I have created future temperature raster (tiff format) in ArcGIS. However I want all pixel's value to be multiply with 10 (constant value). I tried to use con tool and raster calculator in spatial ...
3
votes
1answer
37 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
votes
2answers
29 views

Raster conditional tool unexpected results. What's wrong?

I have a DEM raster (High: 53441, Low: -3444, unit: cms) with negative values, and I want to make all values 100 or less to be 100. I've tried Raster Calculator, and also python. I've got the same ...
0
votes
0answers
49 views

Conditional statement in ArcGIS Raster Calculator?

I am new to Arcmap... I want to make a conditional statement in Raster calculator that checks if the pixel does not contain water or forest value ,, assign them snow as 1 and vice versa... Like the ...
0
votes
0answers
35 views

Reclass a raster based off a percentage of the COUNT values using Con

I have a raster with a VALUE field and a COUNT field. I've sorted (descending) the VALUE field. Now I want to run a Con statement or a reclass to create a new raster based off the top 20% of the SUM ...
3
votes
1answer
119 views

Markov chains, cellular automata, and raster algebra

I need to build a probabilistic cellular automaton for simulating land-use changes and am wondering how to implement this in a GIS. I understand that Markov chains are a way of doing this, and IDRISI ...
1
vote
1answer
40 views

How to replace raster values in one Raster with another [duplicate]

I have two raster files in ArcGIS 10.1, raster 1 and raster 2 all with values and similar spatial resolutions, and overlay in some areas. I want to replace values in raster 1 with those in raster 2 ...
6
votes
2answers
189 views

Adding all Binary Rasters in a Directory Using Raster Calculator in a Standalone Python Script

I have a directory with binary raster files (1 band only) which I need to add in a standalone python script. The problem is the rasters have different number of rows and columns and different ...
1
vote
1answer
49 views

How to find the sum of many raster files in arcmap?

I have a list of 576 raster files for which I need to find the SUM. Obviously using raster calculator one by one would be tedious. Any easy script in Arcpy to do this?
2
votes
2answers
44 views

QGIS 2.8.6 raster calculator: cannot select cells which are below a value in a raster

I have a distance raster map in tif format and I am trying to generate a binary raster where cells below 200m are asigned value 1 and cells above that value are 0. I've converted the distance raster ...
1
vote
0answers
38 views

problem with raster calculator results when subtracting two rasters with different resolutions

I have two elevation datasets which I am trying to subtract to calculate thickness (using ArcGIS raster calculator). The first datset is a tif which is oriented north-south and has a cell size of 5 ft ...
2
votes
0answers
19 views

Looking for a raster calculator C# class

I am developing an application using C# and dotspatial. I need to performs raster calculation a lot..I need a library which helps me to do it..Do you know any library for this purpose? The library ...
1
vote
1answer
44 views

Addition of rasters using raster calculator

I have five classes of rivers as different rasters. and I want to add them all in a new raster file using raster calculator. But when I do this, it creates 16 types of classes, while I want am ...
1
vote
0answers
23 views

Recover failed raster calculator operation QGIS

Users can recover their raster calculator algorithms via the "results" panel in ArcMap (i.e., analogous to viewing one's "history"). Is there a similar function in QGIS? In other words, is there a ...
0
votes
1answer
41 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 ...
1
vote
1answer
68 views

Calculating percentage of cells which are lower than site in Grass GIS?

In GRASS GIS: I have a shapefile with 300 hundred of sites (with height values for each point), and want to calculate the percentage or number of cells (of a given DEM) which are lower than the ...
1
vote
1answer
64 views

QGIS Zonal Stats Plugin - Python Console - compute one specific statistic

I think this is more of a syntax problem that I have here. But I am absolutely not able to figure it out. On a different Linux machine I got the following working: zoneStat = QgsZonalStatistics ...
3
votes
1answer
35 views

QGIS Raster Calculator syntax

I have tried this several different ways and get lots of NaN. I need to specify that in my raster 'test1', I want a certain set of values to equal 1 and the rest to equal zero. For instance, I want ...