Measuring area of raster classes

[MS10]

Hi, i have a raster in which the values represent soil loss (t h-1 y-1) would like to find the area of each class in hectares, but i am unsure of the calculation.

I have reclassified them with the same classes.

The raster properties are as follows:

Attribute table:

The units are in meters (OSGB 1936). using this cell size does 1 pixel therefore represent 0.00029 hectares in this case? (1 sq m = 0.0001 hectares). So 556,236 x 0.00029 = 161.3 hecatres sq - does that seem correct?

Thanks

[FC_Basson · Accepted solution]

If your map units are truly in meters then your raster size is only 1.15m x 0.55m.  Does that seem right?

I would suggest to redo your analysis in a data frame with a true meter system as coordinate system.  Also check in your processing environment settings that the output coordinates are in a meters system.  Then you could indeed calculate the area per raster class as number of cells x cell size x cell size, which would give you a result in square meters.  Divide by 100 x 100 (10,000) to get hectares.

[MS10]

Re-done the analysis in British National Grid (OSGB 1936), seems to have worked. Thanks.

[DanPatterson_Retired]

Your original was in decimal degrees I suspect, projecting the raster I assume, gives you the correct units

[AbdullahAnter]

Yes, you should check your coordinate system and units before calculate the area.

Make sure that your coordinate system is projected, and your units are in meter not in decimal degree, M S.