A tool in some GIS software programs for performing algebraic operations on rasters.
2
votes
0answers
45 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
votes
0answers
71 views
ArcGIS Raster Calculator VS QGIS Raster Calculator
Are there any major differences between ArcGIS Raster Calculator and QGIS Raster Calculator?
3
votes
1answer
43 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 ...
-1
votes
2answers
64 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
0
votes
1answer
41 views
Maintain 8-bit pixel depth in Raster Calculator
Would anyone know how to maintain 8-bit pixels when computing raster calculations in ArcMap?
2
votes
1answer
40 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 ...
1
vote
1answer
67 views
Copy and Paste symbology in Raster?
Hi all,
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:
...
0
votes
2answers
34 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).
2
votes
1answer
71 views
I need help entering a formula into the 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 ...
2
votes
2answers
83 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
91 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
127 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 ...
3
votes
3answers
101 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 ...
7
votes
1answer
139 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
votes
0answers
27 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 ...
3
votes
1answer
183 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 ...
1
vote
1answer
631 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
vote
2answers
296 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. ...
3
votes
1answer
101 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 ...
1
vote
0answers
159 views
Error 000539 in raster calculator in ArcMap 10
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
126 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
151 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
107 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. ...
5
votes
1answer
106 views
Calc bottomline of valleys
Which way do I calculate bottomlines of valleys or even more preceise:
which way do I "find" valleys (for example suggested tectonic faults).
Sample below shows a height profile (profile from line) ...
1
vote
1answer
114 views
Trying to run raster calcuatlor to build an expression for ls factor
I am trying to run a raster calcuatlor but it failed. I believe there is a word that ArcGIS 10 does not understand resolution. Maybe there is a word that needs to be interchangable for this ?
I took ...
0
votes
1answer
251 views
Calculate CTI TWI using raster calculator: Negative values
I am calculating Topographic Wetness Index for a study area using SRTM DEM (90 and 30m).
I understand there are many "flavors" of TWI (CTI).
I have been using: TWI = ln(As +1 / tanB)
where As ...
1
vote
1answer
124 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 ...
2
votes
2answers
173 views
Why does Raster Calculator return GRID ERROR-Unable to open the input grid: 1+FLOATC:\document…?
I'm calculating Simple Ratio (SR) from NDVI using Raster calculator in Arcgis. Here is expression I wrote in Raster calculator.
SR=(1+float[NDVI_apr.tif])/(1-float[NDVI_apr.tif])
But when I evaluate ...
5
votes
1answer
154 views
How to calculate a standard deviation across multiple raster layers?
I have 15 raster layers. Each one shows accumulated precipitation (rainfalls) for the month of April for the same US state during a given year. So, I cover the period from 1997 to 2012. I would like ...
5
votes
1answer
409 views
Working around the raster calculator in ModelBuilder - ArcGIS
I am experiencing a problem with the raster calculator in the Model Builder under ArcMap 10.
I need to combine two layers: a drainage map (issued from a series of previous operations on a DEM) and a ...
0
votes
0answers
61 views
how to calculate the spatial mean in a region in one raster which correspond to another raster? [closed]
I have a raster map(sed) that I want to calculate the spatial mean of specific region and display that as a layer.I do not just one value,I want to display the area too(even if the value is the same ...
8
votes
1answer
327 views
How to make a new raster using con() script in Python?
I'm new to Python and have been trying to code a raster calculator style script. Basically, I want to convert a raster that has values 0 to -10,000 into a raster that is populated by 1s between ...
3
votes
1answer
68 views
Stack sat images and run operation on all
I have about 300 MODIS satellite with different acqusition dates, covering the same area.
I am not used to work with so many tiles at once so I ask for advice. I am working with ArcMap10.1
What I ...
3
votes
2answers
71 views
How to do raster conditional comparisons in .NET?
I am comparing a raster with a constant value by raster calculator. Now I want to do this in a c# code.
Question
Is there any process to do this kind of raster conditional comparison in .net?
2
votes
1answer
50 views
How could I assign point values to a raster stream segment?
I need to assign a point value in raster format to a raster stream segment, which contains the point. See bellow:
The expected result is a segment, whose value is the point value. How could I?
2
votes
2answers
474 views
query raster in ArcGIS 10
I am using ArcGIS 10 (includes spatial and geostatistical analyst). I have a raster (GRID) with a value range of -167 to 18. I would like to query the raster and create a new one with only the values ...
6
votes
3answers
615 views
30,000 data points… can this be reasonably served using openlayers?
I'm trying to tackle a web GIS problem and need to figure out the best strategy. I have a map with 30,000 cells on it forming a grid for the province of Alberta. I have a list of data points for ...
2
votes
0answers
51 views
How do I make a path cross the most possible classes in a raster?
I want to create a function and possibly use Arcmap tools to create something similar to Cost Path. Instead of just choosing the LCP, it must cross through the most different integers. Let's say I ...
5
votes
1answer
409 views
Raster processing with Python or Arc raster calculator
I have 4-band NAIP imagery that require the following processing steps:
Convert to 8 bit unsigned B/W
Reverse (note not inverse) the image, so that dark values appear
light and light values appear ...
3
votes
1answer
166 views
how can I obtain the areas where my rasters overlap, using Qgis?
I have a bunch of raster files showing the distribution of different species of mammals, and I would like to obtain the areas where they overlap, the areas in whitch more than one species can be found
...
3
votes
2answers
367 views
Normalize raster values to 0-255
I need to normalize the values attained from a band ratio to 0-255.
I'm using QGIS. How do I do this?
Any ideas?
4
votes
1answer
448 views
How to reclassify in Rastercalc?
I now need to reclassify, I'm using rastercalc... but I can't get the syntax right!!
I need that values >0 become 1
I found this example...
eq( [relief]@1, [mask]@4, 150 )
so I tried:
( [raster A ...
1
vote
1answer
680 views
using raster calculator
I have a combination method to combine two raster( raster x and y) .
the method is : x+y / 1- min(|x|,|y|)
my problem is about "," character .whats the "," means in the method and how can i use this ...
3
votes
1answer
2k views
How to crop raster layer?
Can anyone tell me how to crop a raster layer in QGIS? I want to make contours from a section of a layer, and including the whole layer will create far more data than I need and slow down the ...
2
votes
1answer
357 views
How to calculate a new raster based on nodata values from original raster, in QGIS?
I'm using the raster calculator from core in QGIS and I need to generate a new tif raster file (mask) from the nodata values of another tif raster file. I tried isnull(), but no luck. Any one can ...
2
votes
2answers
154 views
Is it possible to attain a classified raster with several classes in just one QGIS raster calculator operation?
I'm using qgis' raster calculator and wanted to make a new raster (oraster) from the values of an input raster (iraster). something like:
if iraster>2 then oraster=1; if iraster >4 then oraster=2; ...
5
votes
2answers
927 views
Using individual bands from a multi-band image in ArcGIS 10 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 ...
