Changing the values of the cells in a raster.

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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 ...
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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
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1answer
157 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?
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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
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1answer
579 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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2answers
2k 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
189 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
477 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 ...
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1answer
91 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
211 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 ...
4
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2answers
3k views

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

I've got a really stupidly simple question, but I can't seem to work out how to do it. I have a raster in ArcGIS which has a number of cells with the values 9999, showing that the data could not be ...
4
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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 ...
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5answers
7k 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?
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2answers
731 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 ...