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

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1answer
90 views

QGIS raster calculator “not equal”?

Is there a syntax for "not equal" in the QGIS Raster Calculator? If so, what is it?
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1answer
52 views

Re-sizing Raster file pixels

I have 2 JP2 aerial imagery files that are incorrectly sized. They are 100x larger than the other aerial images but correctly geo-referenced (starting x, y co-ordinates). I believe the issue is their ...
2
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1answer
90 views

Raster layer calculator

In PCI Geomatic, I have two raster layer.raster1 identified like %1 and raster2 like %2. if (%1 <= 10) then %2 = 60 elseif (%1 > 10 and %1 <=50) then %2=80 elseif (%1 > 50 and %1 ...
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1answer
446 views

Map Algebra - Grass GIS (r.mapcalc) merge two raster with NoData value

I have a slope raster and a road raster. The black pixels in the road raster are NoData values and the pink pixels have a value of 1. They don't cover exactly the same area. I want to create a new ...
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0answers
29 views

Layers and variables are not coming out in the raster calculator tool window

I have many shapefiles in the table of content but layers and variables are not coming out in the raster calculator tool window. I placed the cursor the left of the Raster Calculator window, dragged ...
2
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1answer
121 views

Measuring polyline lengths running through a raster - is this possible?

I have a reclassified raster layer with 4 values and a vector layer of polylines. I would like to discover the length of the lines running through each raster value, or the percentage of the lines ...
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0answers
31 views

Create a mask for a 3 Band Raster Image with surrounding white areas

How do I create a mask in order to clip a 3 band raster image so that the surrounding white area does not display. My thinking is to use Raster Calculator to create the mask or cut all three bands on ...
4
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1answer
67 views

Raster Calculator Bug at start

I use ArcGIS 10.1 on a Windows XP. ArcGIS completely shuts down when I attempt to launch the "Raster Calculator" tool. Has this happened to someone else? Any ideas on how to solve this annoying issue? ...
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1answer
59 views

How to select pixel with smallest number in stack raster using Python script in ArcGIS for Desktop?

I have 6 tiff file in ArcGIS which are identical in term of geometry (same frame, same number of row and column). The pixel value of each tiff file is integer and range from 1 to 4. So if I overlay ...
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1answer
421 views

How to “spatially normalize” rasters of different extents to sum values of overlapping cells

How do I add rasters together that are of different spatial extents? I have many, many features that overlap over a large area (entire east coast) and I am looking to sum them "stacked" where they ...
4
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2answers
146 views

How to find buffer radius around raster cell that covers a defined sum of raster cells?

I want to do a neigbourhood analysis on some raster data. I need to know how big a circle around each raster cell must be to include a certain amount of specified raster cells. Let's say that for ...
2
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1answer
159 views

Efficiently check for equal adjacent values in raster calculator

I have a raster consisting of integer values in each cell. I want to check every adjacent cell in a 3x3 grid to see if any one of the adjacent cells has a value EQUAL to the center cell, and if so, ...
3
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1answer
81 views

Cell values to No data

I need to set cell values in one raster to NoData based on another raster. Both rasters have the same extent and some cells overlap. For those cells that overlap I want to set them to NoData in ...
1
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0answers
326 views

How To calculate raster land cover inside overlapping buffer zones?

I am working with a raster land cover file that consists of several land cover types (e.g. forest, buildings, grass ect.) in total there is 40 different land cover types. I have 1200 bufferzonen ...
3
votes
1answer
569 views

How to reclassify raster inside polygon mask, leaving values outside as they are?

I am in the final stages of a landcover classification and need to reclassify thematic raster values that are inside different polygon masks, while leaving the values outside as they are. Can I do ...
2
votes
1answer
149 views

Change Values of Georeferenced Raster

I am using QGIS to georeference B&W images. I have now done this and would like to set the black surround of the image (as a result of the georeferencing) to transparent but this does not work as ...
5
votes
2answers
632 views

How to calculate the number of cells with a given value?

I have a raster file where all cells have values between -3 and 7, no data value is -9999. Have can I calculate the number of cells with a specific value e.g. 6? Can I use the calculator?
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1answer
97 views

Integer rasters referring to the same scale

I'm using ArcMap 10. I want to display the area of simulated avalanches. I want this area to be divided in different colors depending on the thickness of the deposit. I managed to do that. But I want ...
2
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2answers
113 views

How to adjust raster size for usage in raster calculator?

I want to make a visibility analysis of planned wind turbines in my region. I have a DEM raster and a polygon describing the possible area where the wind turbines might be set up. People are ...
0
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1answer
164 views

Map algebra expression with dynamic raster layers

Attached is the model that i am working on. The "To Value" and "From Value" are model parameters and hence subject to change each time according to requirements, This leads to varying number of ...
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1answer
55 views

output file naming

Alright, So I am using a batch process of raster calculator and in the calculator I am using 2 different raster files (meridional and zonal). This calculator will be running for 24 files of each the ...
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1answer
195 views

Raster produced by Con expression not saving

I cannot get a Con expression to work. Or, if it is working, I cannot get the raster produced by the Con expression to save. I have two rasters and I want the positive difference between the two, and ...
0
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1answer
428 views

Raster Calculator in Model Builder

I am trying to calculate a con function for a couple hundred rasters (Meridional and Zonal raster data for wind, each being their own raster file). Is there a way to use model builder with the raster ...
1
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1answer
188 views

Layers and variables box does not exist in ArcGIS raster calculator window?

I have a problem with layers and variables box in raster calculator. The layers and variables box does not exist in the raster calculator window! So I cannot add any raster to the expression. I ...
1
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1answer
496 views

Rasterize vector layers with different extents into identical raster grids with QGIS

I am working on a quite simple spatial potential analysis using QGIS. I have some ArcGIS knowledge, but I am new to QGIS. My task is to identify the functional inner city of a region based on ...
2
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1answer
195 views

Error while using raster calculator in model builder

I am trying to use the model builder for the RUSLE Model. Well this is how the model looks like: So in the raster calculator I have a formula which also involves the rasters generated in the model. ...
2
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0answers
205 views

ArcGIS Raster Calculator VS QGIS Raster Calculator [closed]

Are there any major differences between ArcGIS Raster Calculator and QGIS Raster Calculator?
3
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1answer
417 views

How to exclude some parts of raster classes based on size of area?

I have a raster file with 5 classifications. I've calculated area for all of the classes via Zonal geometry, Arcmap 10. Now, I want to exclude patches which are smaller than 100 sq. km. and ...
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2answers
1k views

How to use Raster Calculator in ArcGIS 9.3? [closed]

Raster Calculator tool is not available in ArcGIS 9.3 , so how to do in 9.3.??? thanks in advance
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0answers
71 views

Maintain 8-bit pixel depth in Raster Calculator [duplicate]

Would anyone know how to maintain 8-bit pixels when computing raster calculations in ArcMap? This is part of a model so I need to keep the image with the original 8 bit, do the calculations, convert ...
2
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1answer
255 views

Nearest Neighbor Focal Statistics and Map Algebra

I would like to use a nearest-neighbor type analysis to iterate over a raster. The nearest neighbor analysis will give a cell value of 1 IF AND ONLY IF the cell being analyzed has a cell value larger ...
5
votes
1answer
438 views

Copy and Paste symbology in Raster?

I am trying to figure it out how can I take a preserved color from a raster I already set up before and then apply the colormap to a new raster file? Here are the details of what occurred: Before ...
0
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2answers
304 views

SAGA, GRASS Raster values to null

I want to make the cells which values "1" to null in QGIS with Grass or Saga tools (exactly Saga).
3
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1answer
723 views

How to reduce all value above certain value using Raster Calculator?

I have a raster with elevations above 2000m that I want to "cut" to 1800m. I cannot quite figure out the correct string and most simple way to do this in the ArcGIS 9.3 raster calculator. I tried ...
3
votes
1answer
349 views

How to enter formula into ArcGIS Raster Calculator?

i have the following formula: L = (l/22,1)^m (l = Flow length) m is calculated like this: m = 0,5 when slope is >4 degrees m = 1,2 * sin^1/3a when slope is <4 degrees (a = slope in ...
3
votes
2answers
470 views

Scale raster in ArcGIS using raster calculator

I have a raster with values ranging from 0 to 8991130624. This raster is actually the result of a cost distance analysis. I want to scale the raster to range from 0 to 1 and take the inverse? so ...
1
vote
1answer
881 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", ...
1
vote
1answer
762 views

ModelBuilder: How2 pipe output of Iterate Raster tool into Raster Calculator tool?

Re: ArcGIS v10.1 ModelBuilder Hello, THE PROBLEM: Using ModelBuilder and map algebra, I want to compute a ten year average grid from a stack of 10. The problem is that only 1 grid (%raster%), the ...
4
votes
3answers
413 views

query raster cell values by point

I have a binary raster (0s and 1s) that I need to query given a set of point coordinates. This is easy enough to do with gdal (gdallocationinfo), but where it get's complicated is that I also need to ...
8
votes
1answer
495 views

Calculating distance from points to different class in raster

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. For ...
0
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1answer
43 views

Isolate And Save Raster Features From Existing Multivalue Raster Map

I have Cyprus Corine map with 44 different types of land use. I want to run a raster calculator query or any other way to isolate the areas with codes 10 to 22 and 26 to 34, all other values 1 to 44 ...
4
votes
2answers
2k 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 ...
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1answer
3k views

reclass, raster calculator

I'm trying to apply seperate equations for different land types. I have created a raster containing only the land type I'm interested in. I then reclassed the values to '0'. My plan was to use the ...
1
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3answers
2k views

QGIS Raster Calculater Syntax

I am trying to use the raster calculator in QGIS to combine a number of rasters. I want to calculate a mean, this is easy: (raster_1@1 + raster_2@1 + raster_3@1) / 3 I then want to create a max. ...
1
vote
0answers
342 views

Raster calculator error 000539 - cannot create weak reference to 'classobj' object

I was - like many times before - trying to clip a raster with the raster calculator (raster * 1 with shapefiles as mask). Now - the following error keeps popping up: ERROR 000539: Error running ...
3
votes
1answer
139 views

Issue with Sextante r.map calculator and modeler

I am trying to build a model with Sextante modeler and the r.mapcalculator algorithm but when I run the model I get the error message: ‘Could not load layer: ‘….’Check sextant log to look for errors ...
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0answers
564 views

Error 000539 in raster calculator in ArcMap 10 [closed]

I'm having trouble averaging 12 rasters in the raster calculator. I keep getting a 000539 error, which I assume means that the syntax in the equation is bad. The problem is I dont know whats wrong ...
3
votes
1answer
282 views

An error in raster calculator in Arcgis

I wrote and ran this formula in raster calculator in ARCGIS. But the following error gets me into trouble. Does anyone have a suggestion to overcome this? Here is the formula I wrote and the error ...
2
votes
1answer
389 views

Question about sizes of input rasters for raster calculation

To calculate any formula (conditional statements/relational operation etc) in the raster calculator in ArcGIS using two different sources of raster images, I'd like to know input rasters must be the ...
1
vote
1answer
210 views

Grass r.mapcalc generates 1 cell map

I'm a GIS student and in my project I need to generate vegetation indexes. I've generated it succesfully yesterday using both python2.7 and grass gui .I'm using WinGRASS-6.5.svn-r54428-453 on Win7. ...