<p>You can convert the image to NetCDF data using <code>gdal_translate</code>. The command line looks something like:</p>

<pre><code>gdal_translate -ot Int16 -of netCDF jpeg_filename nc_filename
</code></pre>

<p>You can use ncl example: <a href="https://www.ncl.ucar.edu/Applications/Scripts/topo_9.ncl" rel="noreferrer">click here</a></p>

CC BY-SA 3.0
2016-10-04T22:04:04.357Z
2016-10-04T23:09:11.627Z
2016-10-04T23:09:11.627Z
Gemechu Fanta Garuma
<p>I have a set of very old precipitation anomaly maps, from 1995-2006 for Brazil. The data of these maps, is to the best of my knowlegde, lost.</p>

<p>I would like to have them digitalized, ie, to NetCDF or another similar gridded format. Is there any tools recommendend for this job?</p>

<p>The figure below is a recent plot, similar to my files.</p>

<p><a href="https://i.sstatic.net/bRF40.gif" rel="noreferrer"><img src="https://i.sstatic.net/bRF40.gif" alt="similar plot"></a></p>

CC BY-SA 3.0
2016-10-05T04:47:05.483Z
Just three points to remember when it comes to interpretation: In arid to semi-arid areas the spottiness of the rainfall distribution doesn't average out on any useful time-scale, and certainly not over an 11 year time-series. Secondly, in mountainous areas like the Andes the local physiographic effects totally eclipse the true regional variation. Thirdly, the map you show looks suspiciously as if it has been generated by a 'contour package', which is often totally misleading because it treats the rainfall in a small rain-guage as an areal maximum or minimum  - which it isn't!.
Gordon Stanger
CC BY-SA 3.0
2016-10-05T12:48:17.323Z
@BarryCarter One can always be surer, but I have put some hours in it and could not find data at this resolution going back to 1995.
kurast
<meteorology><precipitation><software><netcdf>
Digitalizing precipitation data from the image of weather map
kurast
# Digitalizing precipitation data from the image of weather map

(Asked by: username_0 on 2016-10-04)

I have a set of very old precipitation anomaly maps, from 1995-2006 for Brazil. The data of these maps, is to the best of my knowlegde, lost.

I would like to have them digitalized, ie, to NetCDF or another similar gridded format. Is there any tools recommendend for this job?

The figure below is a recent plot, similar to my files.

[![similar plot](https://i.sstatic.net/bRF40.gif)](https://i.sstatic.net/bRF40.gif)

**Tags:** meteorology, precipitation, software, netcdf

> **Comments:**
> **username_1**: Just three points to remember when it comes to interpretation: In arid to semi-arid areas the spottiness of the rainfall distribution doesn't average out on any useful time-scale, and certainly not over an 11 year time-series. Secondly, in mountainous areas like the Andes the local physiographic effects totally eclipse the true regional variation. Thirdly, the map you show looks suspiciously as if it has been generated by a 'contour package', which is often totally misleading because it treats the rainfall in a small rain-guage as an areal maximum or minimum  - which it isn't!.  
> **username_0**: @BarryCarter One can always be surer, but I have put some hours in it and could not find data at this resolution going back to 1995.  

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## 1 answers

### Answer by username_2 on 2016-10-04. Score: 4 | Accepted answer

You can convert the image to NetCDF data using `gdal_translate`. The command line looks something like:

```
gdal_translate -ot Int16 -of netCDF jpeg_filename nc_filename

```

You can use ncl example: [click here](https://www.ncl.ucar.edu/Applications/Scripts/topo_9.ncl)


---

