generate the histogram after apply a mask to a classification image

[Beatriz Pierri Daunt]

Dear all,

I could not generate the histogram after apply a mask to a classification image

I tried to mask the classification image. It has been successfully, but the final raster has no statistics or histogram column. I’ve also tried tho generate the statistics separated, using the “6_populatestats.py” from RSGILB course introduction, but it also failed.

I’ve followed these steps:

# Creating a raster mask from a shapefile, using the extent of the classification image to be masked

inputvector = 'litoralnorte_diss_sul.shp' #thie study area

inputimage = 'ObjBaseClass2010_14.kea' #raster produced by OBIA classification

outmask = 'Litoral_study_area_mask.kea'

vectorutils.rasterise2Image(inputvector, inputimage, outmask,gdalFormat='KEA', burnVal=1)

# Apply mask to classification image

outputimage = 'ObjBaseClass2010_14_mask.kea'

rsgislib.imageutils.maskImage(inputimage, outmask, outputimage,'KEA',rsgislib.TYPE_16UINT, 0, 0)

# Subset masked image to remove unused areas

outputimage2 = 'ObjBaseClass2010_14_LN.kea'

imageutils.subset(outputimage, inputvector, outputimage2,'KEA', rsgislib.TYPE_16UINT)

imageutils.popImageStats(outputimage2, usenodataval=True,nodataval=0, calcpyramids=True)

Best wishes

Beatriz

[Daniel Clewley]

Hi Beatriz,

I think you need to use the populateStats function from the raster GIS module which is designed for RATs and thematic data rather than the one from imageutils, see:

http://www.rsgislib.org/rsgislib_rastergis.html

Thanks,

Dan

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[Daniel Clewley]

Hi Beatriz,

Masking drops the raster attributes so you need to regenerate them. You can do this using populateRATWithStats, something like:

        # Add pixel values to attribute table

        bandStats = []

        bandStats.append(rastergis.BandAttStats(band=1, maxField='Class'))

        rastergis.populateRATWithStats(classification, 

                                       classification, bandStats)

Can you make sure you reply to the list in future rather than just me, then other people will see your question and be able to help.

Thanks

Dan

On 11 May 2017, at 22:08, Beatriz Pierri Daunt <beat...@gmail.com> wrote:

Dear Daniel,

Thank you very much.

It works, but it couldn't generate the class column.

Can you help to edit the column, or to generate the class name column form the subset image?

Best wishes

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[Beatriz Pierri Daunt]

Dear Daniel

Thank you very much!

Best wishes

Beatriz