A tool in some GIS software programs for performing algebraic operations on rasters.
0
votes
0answers
25 views
Problem performing union operation with ArcGIS raster calculator
I'm new to ArcGIS and I'm having some problems calculating the union of two reclassified layers.
Both layer one and two have been reclassified into 3 levels, and display as expected. However, when I ...
0
votes
1answer
42 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
votes
0answers
58 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
89 views
ArcGIS Raster Calculator VS QGIS Raster Calculator
Are there any major differences between ArcGIS Raster Calculator and QGIS Raster Calculator?
3
votes
1answer
59 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
105 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
46 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
49 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 ...
2
votes
1answer
83 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
46 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
79 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
98 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
97 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
182 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
112 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
174 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
218 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
743 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
360 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
106 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
182 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
135 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
169 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
110 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
141 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
284 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
143 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
188 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
171 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
449 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
64 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
366 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
70 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
72 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
53 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
503 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
637 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
420 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
171 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
385 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
472 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
717 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
364 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
164 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
985 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 ...
