1

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:

enter image description here

when zoomed in, it looks like this (you can see the 1km x 1km now looks like a rectangle) :

enter image description here

How can I convert this TIFF file to 1 degree x 1 degree data?

Looks like this (Excel file or CSV file) :

enter image description here

and when rendered as a map, it looks like:

enter image description here

Improve this question
1
  • 2
    If you take the Tour, it emphasizes the importance of asking One question per Question. We use a Focused question/Best answer model, so this then that questions really ought to be researched separately. In this case, you seem to have an XY Problem, since converting to shapefile won't be much help in generating a coarse summary. You should focus the question (and title) on processsing a raster with specified cell size to a coarse summary table.
    – Vince
    Jul 8, 2021 at 12:04

2 Answers 2

Reset to default
1
+50

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: enter image description here 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 ): enter image description here 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). enter image description here 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: enter image description here 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.

Improve this answer
2
  • Thank you so much! I will try!
    – Siwei
    Jul 17, 2021 at 8:35
  • 1
    works like a charm! thank you so much!
    – Siwei
    Jul 23, 2021 at 4:15
1

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.

Improve this answer
1
  • thank you! your clue is good, if gives me images and the detailed steps ( which menu to click ... ) will be great. but now it's not necessary. this question is closed. anyway, your answer is upvoted by me.
    – Siwei
    Jul 23, 2021 at 4:18

Not the answer you're looking for? Browse other questions tagged or ask your own question.