1

I have a global land cover map, which has the following properties: Name ESACCI-LC-L4-LCCS-Map-300m-P5Y-2010-v1.6.1 Path C:\QGIS\ESACCI-LC-L4-LCCS-Map-300m-P5Y-2010-v1.6.1.tif\ESACCI-LC-L4-LCCS-Map-300m-P5Y-2010-v1.6.1.tif

CRS EPSG:4326 - WGS 84 - Geographic
Extent  -180.0000003392726740,-89.9999950369175963 : 179.9999897345625186,90.0000000000000000
Unit    degrees
Width   129600
Height  64800
Data type   Byte - Eight bit unsigned integer
GDAL Driver Description GTiff
GDAL Driver Metadata    GeoTIFF
Dataset Description C:\QGIS\ESACCI-LC-L4-LCCS-Map-300m-P5Y-2010-v1.6.1.tif\ESACCI-LC-L4-LCCS-Map-300m-P5Y-2010-v1.6.1.tif
Compression LZW
Band 1  •   STATISTICS_APPROXIMATE=YES
•   STATISTICS_MAXIMUM=220
•   STATISTICS_MEAN=188.20256246321
•   STATISTICS_MINIMUM=10
•   STATISTICS_STDDEV=53.693285876722
•   STATISTICS_VALID_PERCENT=100
More information    •   AREA_OR_POINT=Area
•   Authors=Pierre Defourny ,Eric Van Bogaert 
•   Copyright=Copyright ©UCL Geomatics, BELGIUM 1999-2012
•   Generate by=gdal_ocl
•   process begin time=2015-08-24T20:26:40
•   process finish time=2015-08-24T20:51:20
Dimensions  X: 129600 Y: 64800 Bands: 1
Origin  -180,90
Pixel Size  0.002777777701186999893,-0.002777777701186999893

To clip continents I used shp file of countries, which has following properties: Fixed geometries Source

MultiPolygon?crs=EPSG:4326&field=OBJECTID:double(19,0)&field=COUNTRY_NA:string(254,0)&field=Shape_Leng:double(32,15)&field=Shape_Le_1:double(32,15)&field=Shape_Area:double(32,15)&uid={afd52bdd-db05-480d-acf5-932252071748}

Storage Memory storage Comment

Encoding
UTF-8
Geometry
Polygon (MultiPolygon)
CRS
EPSG:4326 - WGS 84 - Geographic
Extent
-179.9999999999999716,-89.9999999999999432 : 180.0000000000000000,83.6333923340000638
Unit: degrees
Feature count: 279

enter image description here

I collected African countries to be used as mask. Africa was clipped and the new layer has the following properties:

Path   C:\Users\User\AppData\Local\Temp\processing_049cf2b8a5b041639ace295d17d3d405\1c8919fd7e01488e8d7dacc10cd06c93\OUTPUT.tif

CRS
EPSG:4326 - WGS 84 - Geographic
Extent
-25.3611104118373092,-46.9805542601757296 : 73.7444424111124590,37.5444434092434918
Unit
degrees
Width
35678
Height
30429
Data type
Byte - Eight bit unsigned integer
GDAL Driver Description
GTiff
GDAL Driver Metadata
GeoTIFF
Dataset Description
C:/Users/User/AppData/Local/Temp/processing_049cf2b8a5b041639ace295d17d3d405/1c8919fd7e01488e8d7dacc10cd06c93/OUTPUT.tif
Compression

Band 1
STATISTICS_APPROXIMATE=YES
STATISTICS_MAXIMUM=220
STATISTICS_MEAN=115.01767969776
STATISTICS_MINIMUM=10
STATISTICS_STDDEV=74.622799277297
STATISTICS_VALID_PERCENT=30.52
Band 2

More information
AREA_OR_POINT=Area
Authors=Pierre Defourny ,Eric Van Bogaert 
Copyright=Copyright ©UCL Geomatics, BELGIUM 1999-2012
Generate by=gdal_ocl
process begin time=2015-08-24T20:26:40
process finish time=2015-08-24T20:51:20
Dimensions
X: 35678 Y: 30429 Bands: 2
Origin
-25.3611,37.5444
Pixel Size
0.002777777701186999893,-0.002777777701186999893

To measure area I used r.report plugin. The result is the following: enter image description here I reprojected the clipped layer to 102022 and r.report plugin was running again. The result is the following: enter image description here What mistakes have I make?

  • Making some guess work. It seems that r.report knows how to compute areas from EPSG:4326 long/lat coordinates and show results in square kilometers. I guess that when you converted data into 102022 (what it is?) the coordinate values remained the same as in EPSG:4326, so within range -180 - 180 and -90 - 90, but now they are interpreted as meters. – user30184 May 20 at 12:13
  • EPSG:102022 Africa Albers Equal Area Conic – Ferenc Mics May 20 at 16:08
  • OK, actually it is an ESRI code epsg.io/102022 but if QGIS knows it as EPSG:102022 then it should not matter. – user30184 May 20 at 16:28

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