Pixel Size 0.002777777701186999893,-0.002777777701186999893To clip continents I used shp file of countries, which has following properties: Fixed geometries Source

11 months ago 6 Replies
FM
Ferenc Mics
4 years ago

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 RS 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,-0.002777777701186999893To 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} 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 I collected African countries to be used as mask. Africa was clipped and the new layer has the following properties: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 29882300 km2. I reprojected the clipped layer to EPSG 102022 Africa Albers Equal Area Conic and r.report plugin was running again. The result is really strange for me. What mistakes have I make?

12 Likes

Replies

Ferenc Mics 4 years ago

Sorry for long post, I did not want to omit anything.

0 Likes
David Lade 4 years ago

why is 30 mio km2 for africa strange?

0 Likes
Ferenc Mics 4 years ago

0,002558 km2 is a strange result after reprojecting to Africa Albers Equal Area Conic.

0 Likes
Billy Hales 4 years ago

I agree with David Lade. The area is close to the area of Africa (30.37 million km²), according to Google. The resolution of the raster is probably due to some internally set number of columns/rows of pixels.

0 Likes
Billy Hales 4 years ago

It looks like whatever command you used to 'reproject' the data merely redefined the projection to Africa Albers Equal Area. Basically, it suggests that it switched the degree unit with km2.

0 Likes
Akhilesh Kumar Karna 4 years ago

First of all, clip the data to the extent of Africa. Then reproject.

0 Likes