Changing the values of the cells in a raster.

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2answers
486 views

How do you use 'reclass' in GRASS?

It could be user error, but for some reason, the reclass tool is just hanging and hanging... QGIS 1.8 Compiled against GDAL/OGR 1.9.2 Ubuntu 12.04.1 Running the tool from the Sextante toolbox Input ...
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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 ...
8
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2answers
2k views

How to reclassify a very large land cover dataset?

Consider the NLCD2001 Land Cover dataset for Alaska (download link). I need to reclassify this dataset so that only pixels of value 41, 42, and 43 are preserved; all other pixel values should become ...
3
votes
1answer
177 views

How to get the “absolute value” of a raster cell in QGIS?

I have a raster map (-100 to +100) and I need to get all the minus values as absulute values (-100=100; -99=99...). How can I do this? Is it something like reclassify?
2
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0answers
199 views

Reclassifying a field in vector files in ArcGIS [duplicate]

ArcGIS has a reclassify tool that works with Raster files only. Is it possible to have the same functionality for a vector file? On the basis of one of the fields in a feature class, the tool ...
3
votes
1answer
638 views

Issues with arcpy.sa.Reclassify

I have a raster file with classifcation codes, and want to reclassify valid codes to 1, and all others to 'NoData'. RMAP2 = arcpy.sa.RemapValue([[3.2, 1], [4.1, 1], ...
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votes
2answers
3k views

How to change null values raster values to 0 in QGIS?

I need help... I'm having problems with QGIS. I have some rasters that appear to have null values, even though I reclassified them to obtain a boolean raster :( How can I change the NULL values to 0?
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0answers
192 views

Reclassify ESRI raster using variables from a SQL Server table (connecting with pyodbc)

I am trying to reclass a raster file (representing vegetation and land cover types) using values stored in a SQL Server Express table. I have a set of ~400 species records in the table, with each row ...
2
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1answer
487 views

Creating a constant elevation raster with multiple attributes

Is it possible to create a raster with a constant value with multiple attributes? Such as: rowid value count Name 1 630 36000 Forest 2 630 75000 Anthro 3 630 2600 ...
4
votes
1answer
95 views

What proportion of the 240m area sensed by MODIS must be forest before it is defined as forest?

MOD12 is a MODIS product at 240m resolution. Landsat produces 30m resolution products, which I resampled to 240m resulting in a raster of proportion forest cover in each 240m pixel (based on the mean ...
4
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1answer
1k 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 ...
4
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1answer
230 views

Reclass all values < 0 to -9999 in PostGIS

I have a tiled raster in a PostGIS table and I would like to change the value of all pixels which have values less than 0 to -9999. How should I do this? I suspect it involves ST_SetValue and ...
5
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2answers
3k views

Reclassify raster values of 9999 to NoData, leaving all other values alone, in ArcGIS Desktop?

I have a raster in ArcGIS which has a number of cells with the values 9999, showing that the data could not be generated for that cell. I want to convert all of these 9999 values to NoData, so that ...
4
votes
1answer
2k views

ReClassify Vector Data Between Values using ArcGIS Desktop?

I would like to be able to take all values between 1 and 10 and have a field define them as 1, and all values between 10 and 20 and set them to 2, how do I do that with vector data? I read how to set ...
11
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5answers
8k views

How to perform Raster Reclassification in QGIS?

Is there a way to do reclassify a raster image to Qgis? In Arcgis you can do that in Spatial analyst Tools→Reclass→Reclassify Any ideas?
6
votes
2answers
752 views

Raster to Vector: Displaying classes in Vector Layer - GRASS GIS

I use Maximum Likelihood classification to classify Landsat image into two landuse classes - one of my interest and rest including all others. Inorder to assess the accuracy I export it in vector ...