Error: No appropriate method, property, or field...

5 次查看（过去 30 天）

Sarah Yun 2019-11-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/491570-error-no-appropriate-method-property-or-field

评论： Patrick Tully 2020-11-21

Hi,

I get the following error when trying to calculate area of land in two landsat images (NDVI and NDWI) covered by vegetation.

'No appropriate method, property, or field 'SampleSpacingInWorldX' for class 'map.rasterref.MapCellsReference'.'

Please help.

Here is the code.

Whay is causing the error?

%% Combine NDWI and NDVI to calculate proportion of the land covered with vegetation
% Load the NDVI and NDWI tif
NDVI = geotiffread...
 ('../data/NDVI.tif');
info = geotiffinfo...
 ('../data/NDVI.tif');
NDWI = geotiffread...
 ('../data/NDWI.tif');
%% Set thresholds
NDVI_threshold = 0.4;
NDWI_threshold = 0.075;
%% Apply thresholds
veg = (NDVI >= NDVI_threshold);
water = (NDWI >= NDWI_threshold);
land = (NDWI < NDWI_threshold);
% Find areas of  land and vegetation
land_veg = (NDVI >= NDVI_threshold & NDWI < NDWI_threshold);
% Get  number of pixels of different surfaces
tot_px = numel(NDVI);
land_px = sum(land(:));
land_veg_px = sum(land_veg(:));
[ERROR AT NEXT STEP]
% Find percentage of land covered with vegetation
cell_area = (info.SpatialRef.SampleSpacingInWorldX.*...
    info.SpatialRef.SampleSpacingInWorldY)./1000000; % (km^2
[No appropriate method, property, or field 'SampleSpacingInWorldX' for class
'map.rasterref.MapCellsReference']