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I have a TIFF file: http://files.sweetysoft.com/image_after_2021_05_19/3653/China_2020_1km_UNadj.tif
It contains data , e.g. GDP in 2005, the smallest unit is a pixel ( 1km x 1km ). when opened in ArcMap 10, it looks as below:
when zoomed in, it looks like this (you can see the 1km x 1km now looks like a rectangle) :
How can I convert this TIFF file to 1 degree x 1 degree data?
Looks like this (Excel file or CSV file) :
and when rendered as a map, it looks like:
This is straightforward, just has a number of steps to it. If you take the first raster (that you linked) and run it through the Aggregate tool ( arctoolbox -> spatial analyst tools -> generalization -> aggregate ) in the Spatial Analyst toolbox, you can add GDP values for neighboring cells and downsample to 1 degree by 1 degree. To do this, set the "Cell factor" to 120 (1 degree / 0.008333 original resolution), and use the SUM Aggregation technique:
If you look in the new raster's Properties window, the resolution is 1 degree (and type is float 32-bit). You'll need to convert it to integer type (to be able to turn it into vectorized data), so run it through the Int tool (arctoolbox -> spatial analyst tools -> math -> int ):
Next, run the integer value raster through the "Raster to Point" tool (arctoolbox -> conversion tools -> from rasters -> raster to point). Be sure to set the "Field" value to Value, and set the output to either a feature class or Shapefile (saved in Windows file system).
Then, "Add XY Coordinates" (arctoolbox -> data management tools -> features -> add XY coordinates) with your feature class as the single parameter, to get the longitude and latitude:
Now you have all your information in a single table! You can run the "Table to Excel" tool ( arc tool box -> conversion tools -> excel -> table to excel) to get this to an Excel document, but I find it's easier to Select All rows and right-click in the Attributes Table (left margin) to "Copy Selected" rows and simply paste in a new Excel worksheet.
If you have spatial analyst extension, use a combination of (1) "Create fishnet" to create your output polys aligned to a 1 degree grid, (2) "neighborhood statistics" to aggregate the data up to that size, and (3) "raster to polygon" tool to convert the raster to vector polygons. Then open that attribute table and export that to text for CSV.
