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

learn more… | top users | synonyms

1
vote
1answer
54 views

Calculating slope between 5 and 10 percent using raster calculator of QGIS?

I went to Raster --> Analysis --> DEM (Terrain Models) to compute slope. The slope ranges from 0-39.2311. Now I'm unsure of the correct way to calculate slope between 5-10% in the raster ...
0
votes
1answer
35 views

ArcGIS 10.1 SA Raster calculator: Multi-raster conditional with nodata

I have a question regarding the Con statement when used in the SA Raster Calculator. I am reclassifying a raster (categorical, integer) based on my own mappings but also on another raster (for some ...
3
votes
1answer
38 views

Performing raster calculations along line feature or within polygon using QGIS?

I need to add a value to a dem file along a polyline feature or within a polygon. How can I add 100 to the values of the raster cells intersected by my line feature or within my polygon feature. I ...
0
votes
1answer
47 views

Algorithm for soil texture calculation

Ok. I have percent sand/silt/clay values for 30 sample points on grid. I used these values to create 3 interpolated IDW rasters. I want to somehow (I think in raster calculator) to make a code using ...
1
vote
1answer
34 views

Using OR and ISNULL in Raster Calculator

I am using ModelBuilder for ArcGIS Desktop 10.2 I have the following code in the Raster Calcualtor which works in some cases but not in others. Int(Con(IsNull("%A%")|"%A%"== 0,"%B%",float(%Max%) + ...
1
vote
1answer
1k views

How to make polygon volume in TIN surface?

I want to measure surface volume of an area in different elevation layer. For measuring the surface volume I have to make a Polygon Volume as well. I have problem with making this polygon over the ...
1
vote
1answer
52 views

QGIS raster calculator error: cannot convert float infinity to integer

I just made a simple subtraction between two raster layers and got the error: Traceback (most recent call last): File ...
0
votes
0answers
18 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 ...
4
votes
2answers
77 views

Expand raster nodata area (shrink values area)

I need to fix a raster that's been inappropriately resampled along the nodata edge. The bad data area is narrow, pretty much a single cell. The value range is too variable to use a simple "erase less ...
3
votes
2answers
43 views

Using Con in Raster Calculator of ArcGIS for Desktop?

I have two images, "dvel.img" and "evi.img", and i want to extract water related pixels. The condition is: (("dvel.img" <= 0.05) & ("evi.img" <= 0.3)) I want to get an output by putting ...
5
votes
1answer
940 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 ...
0
votes
1answer
40 views

Raster Calculator Parsing Error

I am using three cons with raster calculator to give four different results depending on the values within two rasters, aclip20151111 and sclip20151111. There are four results I want; RESULTA, ...
1
vote
1answer
32 views

Where command in raster calculator Arcgis

I have two rasters that I wish to combine to give a third raster that describes spatially where multiple conditions of both rasters are met. For example, say my two input rasters are raster A and ...
1
vote
1answer
18 views

Assign values to raster in QGIS

I'm stack with a simple issue. I have a raster (DEM) and what I want to do is to assign -9999 where the pixel value of the DEM is 500 and leave all the other values as the original ones. I tried: ...
0
votes
0answers
18 views

Map algebra with raster [duplicate]

I am doing some map algebra with a raster however the result is not correct. I think it is because the cellsize (x,y) is in decimal degree (0,00027777778, 0,00027777778) and the z values are in meter. ...
0
votes
0answers
33 views

Adding Raster by raster calculator gives no values

I`m trying to add several raster files to one (like a merge). I tried using the raster calculator (in ArcGIS 10.2.2 and in QGIS 2.8.1 and QGIS 2.10). Anything I do leads to rasterfiles which have only ...
0
votes
1answer
19 views

How to fix a calculate value tool to work in a large model and skip featureless rasters?

I'm attempting to run a model that contains some rasters that do not have any features after being processed through my raster calculator. I have a calculate value tool from a previous question that ...
8
votes
2answers
4k 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 ...
1
vote
0answers
24 views

Map Algebra with Zero-inflated regression weights

I have a non-normal count variable y and 6 rasters x1 to x6, each mapped onto a (n x n) grid. I have applied a zero-inflated negative binomial regression using the pscl package of R. I now need to ...
1
vote
0answers
28 views

Determining mathematical expression for Boolean logic with 5 raster layers in ArcGIS for Desktop? [closed]

I have 5 layers in ArcGIS 10.2 for Desktop, and i want to apply Boolean Logic. What will be the mathematical expression in "Raster Calculator". I know that for to layers expression will be like ...
0
votes
1answer
66 views

Calculating the difference between two grids in percent with QGIS

I'm using the QGIS GDAL Raster Calculator to get the difference in percent between two grids. Grid A contains an integer, and grid B contains an integer which may be the same as or larger than the ...
1
vote
1answer
167 views

Raster Calculator in QGIS returning 'nan' values

I am attempting to add two rasters using the QGIS raster calculator and every output ends up as 'nan'. There were no problems with the raster calculator before trying to add these rasters, so I am ...
2
votes
3answers
87 views

Raster calculator : How to make 0 + NoData = 0?

I have a point data layer (vector) that I converted to a raster layer. I want to replace the NoData value (between each raster point) in the point raster layer by 0. So, I made a background raster ...
10
votes
1answer
1k views

Calculating distance from points to different class in raster using ArcGIS Spatial Analyst?

I am looking for some advice on how to calculate the distance from a point to a different class of a raster. Specifically, I have observations (points) of animal use overlaid on land cover data. ...
1
vote
1answer
281 views

Why does the composite raster pixel values not cover the full range of RGB and what does this mean for reclassification after conversion to int?

I have about 30 or so composite rasters in IMG format that I need to 1.) Preserve the date that the raster was created and 2.) Combine all of them. My workflow is: Step 1: raster calculator, ...
1
vote
1answer
94 views

Multiply raster by Numpy derived float value

So I have a python script that uses numpy to calculate the mean of a field, then I try to use that mean value in a raster multiplication as follows: na = ...
5
votes
1answer
775 views

Calculating Topographic Exposure with Raster Calculator

I need you help trying to calculate Topographic Exposure (TOPEX) on a DEM in ArcGIS. I am trying to figure out wind exposure on a DEM with 25m cells. There is a great blog post where someone explains ...
1
vote
1answer
105 views

DEM Processing in ArcMap

I have a question regarding DEM. I have downloaded SRTM DEM 30 m and I did a mosaic for the data using Mosaic tools in Arcmap to a Mosaic to a new raster. However, I got a DEM raster with values of ...
0
votes
0answers
48 views

Can I run hydrology tools within focal statistics?

I've been trying to identify ridges and valleys from a DEM and have been using hydrology tools. I identify rivers as areas that have a value on an accumulation raster above a threshold, then valleys ...
2
votes
1answer
50 views

Iterate - Raster Calculator - 8 Day MODIS LST to Monthly Avg

I have 8-day MODIS Land Surface Temperature data from 2009-2013. I have used Model Builder to extract the LST_day and LST_Night Subdatasets (in different model runs). What I am attempting to do next ...
1
vote
2answers
598 views

QGIS's raster calculator— running as a batch process?

I have a series of raster files (150 or so) that I need to multiply by a baseline raster. Unfortunately, the series of rasters have a different cell size (30m×30m i.e. .00027777778 degrees ...
0
votes
1answer
51 views

Adding multiple rasters produces unexpected results. I have set the data extent to the same in all rasters

I am trying to add three rasters together. I'm trying to figure out where I am going wrong so I am going to list out what I am doing: I have Raster_1, Raster_2 and Raster_3. Raster_1 and Raster_2 ...
1
vote
3answers
68 views

Making raster output based on comparison between 2 input rasters using ArcGIS for Desktop?

I have 2 input rasters of rainfall for summer/winter and I want to make a 3rd output based on which one has the max value for that cell. So if the max value at the cell is summer it will assign 1, or ...
1
vote
1answer
702 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)) ...
4
votes
3answers
149 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 ...
0
votes
0answers
75 views

Adding rasters with GeoTools

I'm using org.geotools.process.raster.AddCoveragesProcess class, to add two raster's with same resolution and buonding box. I get the following exception java.lang.IllegalArgumentException: Range ...
3
votes
1answer
671 views

How to add rasters of different sizes with Arcmap or Qgis raster calculators?

I've got 8 rasters all of different sizes. What is the proper syntax, for the raster calculators of either Arcmap or Qgis, that will output a raster that covers the extent of all my data not just the ...
1
vote
0answers
77 views

Kernel Density Estimation Crimestat

I calculated a series of Kernel Density Estimations in CrimeStat (because more parameters can be set than in the built-in tool in ArcGIS) and then imported the results into ArcMap. I wanted to combine ...
1
vote
1answer
43 views

Parsing error : invalid syntax (line 1) from ArcGIS Raster Calculator?

I have a (Aspect)raster (32bit, floating point,overall 2.9GB) of a landscape and need to devide it with π/180, in order to get the mean aspect later. My raster calculator (Spatial Analyst --> Map ...
3
votes
0answers
328 views

Single Tree detection

I was wondering how I could extract "crown area" of single trees in a forest from a high-resolution image with only 3 band (RGB) in ArcMap. ( No NIR to use NDVI as any threshold). I need a fast ...
1
vote
2answers
45 views

How can I stop my map algebra being limited to the size of my smallest raster?

I have five input rasters and I'm using map algebra to find areas where all of them have a value over 75, areas where all of them are over 25, and areas where one or more are under 25. I can do this ...
1
vote
1answer
149 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') ...
2
votes
1answer
75 views

How can I add a Raster Calculator tool on QGIS Processing Modeler?

I'm trying to add the Raster Calculator to a model I'm creating using the Processing Modeler of QGIS 2.6 Brighton. It does not allow me to add the normal Raster Calculator tool under Raster, so I ...
4
votes
1answer
191 views

Raster Calculator Iteration

I have a large number of rasters and I want to add 1 to each of them (e.g. each raster's values currently range from 0 to 1, and I want to make them range from 1 to 2). I believe modelbuilder, using ...
0
votes
0answers
35 views

Can I multiply fractions in map algebra?

I have a couple of rasters that show % of success in different things. I want to calculate the overall probability of success. The numerical values are integers so they represent the percentage. This ...
0
votes
0answers
74 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 ...
0
votes
0answers
50 views

How can I replicate focalmean with focal statistics

Hi I am trying to get rid of some small gaps of no data in my rasters. I would previosly have used focalmean but it is no longer available. I've tried what I expected to work but I'm getting errors. ...
0
votes
1answer
50 views

count band numbers from multiband raster image

My raster image has 10 bands (10 bands are 10 year), cell values of each one are 1, 2, 3. One is negative anomaly, 2 is no change area, 3 is positive anomaly. Now I want to find how many years out of ...
0
votes
0answers
39 views

how I can get raster calculator select files with similar names?

The idea is to select raster files with parts of similar name, for example: Filenames (in between many others raster with other names, but in the same folder): 28feb11evs 28feb11evv 28feb11pr ...
0
votes
2answers
78 views

Computing View Distance in One Direction from Point on Elevation Raster in PostGIS?

I'm a software developer just getting into GIS, so please forgive me if I don't use proper lingo, or if I use proper lingo incorrectly! I have a raster of elevation data. For a given point in the ...