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I have glacier thinning data from https://github.com/dshean/hma_mb_paper/tree/master/data/mb in the form of CSV, which contains essentially everything, dh, dt all the parameters required.

I want to create a map shown in the picture based on the data from CSV and RGI(Randolph Glacier Inventory that'll provide the glacier outlines in the form of polygons).

How do I do that? I am only aware about adding points (in this case, glaciers from x, y data) from the CSV.

enter image description here

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  • If I understand this, the github files you point to don't have the glacier polygons, only some data for each glacier, one per row. Do the glacier outline polygons come from this "Randolph Glacier Inventory" - where is that?
    – Spacedman
    Apr 13, 2021 at 20:09
  • Yes, I should've clarified it, the outline polygons indeed will be sourced from Randolph Glacier Inventory Apr 13, 2021 at 20:24
  • The way to do this in outline is to 1) load the glacier polygons as a layer, 2) load the CSVs as a non-spatial table layer, then 3) use a "join" to relate the CSV data to the polygons, then you can plot and style using those values. Once I get this 990Mb glacier zip file downloaded I might make a full answer...
    – Spacedman
    Apr 13, 2021 at 20:27
  • In any case, I think the proj4 string given in the readme for those points is wrong, and I've added an issue to the repo: github.com/dshean/hma_mb_paper/issues/1
    – Spacedman
    Apr 13, 2021 at 21:14
  • Oh please don't download the entire data, it'll only be a wastage cuz I need data only for the Alaknanda basin as shown in the picture. Apr 13, 2021 at 21:14

1 Answer 1

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The polygons might be sourced from the GLIMS Glacier Database. You could then spatially join the point data you have found to these polygon outlines.

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  • If you are not sure how to import CSV data into QGIS (or other GIS software), have a look at Importing Spreadsheets or CSV files.
    – Eric West
    Apr 14, 2021 at 18:52
  • Actually, there's an issue as the csv has mentioned a proj4 string for it's coordinate system which doesn't match up with the default. Apr 14, 2021 at 20:11
  • In QGIS, set a Custom Coordinate Reference System. In the Format section, select Proj String. In the Parameters section, paste the PROJ4 string: +proj=aea +lat_1=25 +lat_2=47 +lat_0=36 +lon_0=85 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs
    – Eric West
    Apr 15, 2021 at 14:07
  • Yes, I did that. The polygons however are in the default EPSG 4326. How do I perform spatial join on them. I mean which data set should I reproject? Apr 15, 2021 at 18:44
  • I suggest using Reproject Layer on the points, to get all layers in EPSG 4326. This is by far the most common geographic coordinate system, and is assumed by GeoJSON and other file formats.
    – Eric West
    Apr 15, 2021 at 20:59

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