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

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2
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2answers
53 views

Using Con in Raster Calculator of ArcGIS for Desktop? [closed]

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 ...
4
votes
2answers
109 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 ...
0
votes
1answer
54 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
37 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
23 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
47 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
22 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 ...
1
vote
0answers
30 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
105 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 ...
3
votes
1answer
100 views

Calculate Volume over sloped ground in GRASS GIS

I am trying to do some volume calculations on a DEM with GRASS GIS. However, I believe r.volume measures everything from 0. The ground underneath the pile I'm measuring is sloped. I would ...
1
vote
0answers
27 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 ...
2
votes
1answer
398 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
133 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 ...
1
vote
1answer
168 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
74 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
80 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 ...
0
votes
1answer
58 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
1answer
52 views

How to combine bands from different rasters using the global mapper raster calculator?

I am wondering how to specify what raster you are getting the band from in the global mapper raster calculator? When you open it with a more then one raster open you can check the boxes to define ...
1
vote
3answers
78 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 ...
4
votes
3answers
260 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 ...
1
vote
0answers
96 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
61 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 ...
1
vote
0answers
98 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 ...
1
vote
2answers
59 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
297 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
105 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
356 views

Raster Calculator Iteration in ModelBuilder?

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
1answer
49 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 ...
1
vote
1answer
126 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
62 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
50 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
1answer
74 views

How do I input this function to “Raster Calculator” in Model Builder , in ArcGIS 10.2? [closed]

The raster files that function refers are as follows: Precipitation (o “Raster” in figure 1): Variable CN_2S_7ma: Constant CN_8S_7ma: Constant The mathematical function that must be entered is as ...
1
vote
1answer
640 views

Using Raster Calculator expression in Python

I've posted about this problem before but I've got a few new questions. So here's the problem. I have two rasters containing bathymetry data: one containing the bathymetry of the sea floor, we'll ...
0
votes
2answers
165 views

Expressing a Raster Calculator expression with Math Toolset

So here's the problem. I have two rasters containing bathymetry data: one containing the bathymetry of the sea floor, we'll call this raster1, and another containing the difference between two ...
2
votes
1answer
71 views

QGIS Treat null as zero in raster calculator

In QGIS - I have an irregularly shaped raster - I wish to clip an irregular area out of it (call it raster A) with that area set to null. I masked the area (vector polygon) I want to remove and used ...
1
vote
1answer
550 views

Multiple CON Expression in ArcGIS Raster Calculator

How can I write the following conditional statement with CON? If ((VALUE = 20 OR IF VALUE=24) then assign value 0, else 1) Con(("Raster1", 0, 1, "VALUE =20")|("Raster1", 0, 1, "VALUE =24"),0,1) I ...
1
vote
1answer
98 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
votes
0answers
96 views

QGIS RGB image to HSL (Hue Saturation Luminance)

is it possible using QGIS (2.10) on windows to convert an RGB image file to HSL (Hue Saturation Luminance) format. I've seen various formulas for this written in Java however they only seem to be for ...
1
vote
1answer
128 views

Reclassify in QGIS using Raster Calculator?

I have downloaded data from the USGS to create a Map for a malaria risk in east africa but my question is only about the actuall Input in the Raster Calculator. I have a RFE Tiff that shows the ...
1
vote
1answer
75 views

Edit raster classification manually using polygons - 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 ...
0
votes
1answer
61 views

Multiply a stack of floating point rasters( composite raster ) with a constant

I am trying to multiply a floating point stack of rasters (10 layers) with a constant and round up to the next integer. I have the formula RoundUp(10*composite_raster) in raster calculator, but for ...
1
vote
0answers
29 views

Problem with making raster from Aspect and wind direction data [duplicate]

I know its not correct to ask for work flow, but I am learning by doing and now I don't know how to move on. I'm trying to make new raster which will represent the facing sides of hill around a ...
0
votes
0answers
45 views

Spatial segregation from a raster of racial distribution in the USA

I am trying to measure the degree of racial segregation at some geographic level (let's say the county level, for simplicity) in the USA. I have a shapefile with these geographic units. To do so, ...
1
vote
2answers
377 views

Masking out places with elevation below 5 m from a DEM

I have a DEM of a study region; I want to modify the DEM in order to reflect the coastline outlook when the sea level was 5 meters higher than today. What I have done so far is to use 'Raster ...
2
votes
1answer
44 views

script to draw a square where the raster pixels contained within are a certain type and greater than X

I have a raster containing different pixel values and I am interested in having squares drawn around areas that are at least X m^2 and containing at least Y type of pixels. The data looks like this, ...
1
vote
0answers
305 views

Why does every raster calcuation I try return with NAN values?

I am trying to work with DEM rasters from the USGS using the raster calculator. I have tried to change the units from meters to feet using an expression such as: "ned10m45111h8@1" * 3.28 However ...
1
vote
1answer
130 views

Trouble using gdal utilities in python (no output files created)

I am trying to use gdal utilities like gdal_polygonize in python to polygonize my raster image but I'm having trouble understanding the commands. What I mean is in some places the command is of the ...
0
votes
0answers
32 views

QGIS 2.6 Raster Calculator output is smaller than expected

I have used Raster Calculator to merge several raster layers. The layers were all created using geographical features in the same transect, but as the features are not evenly spread, the raster layers ...