Process shapefile

Created on Saturday 24 October 2020, 12:52

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  • ID
  • Project
    Metabolism of Cities Data Hub
  • Status
  • Priority
  • Type
    Process shapefile
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  • Subscribers
    Paul Hoekman

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This is the whole river network for Portugal. I believe it is definitely useful.

I have a question, I choose this shapefile and I process it, then in my city map overview if I choose rivers, does the system makes a direct crop of the municipal boundaries for example and the rivers that pass through? Or it loads just the visible ones? I am thinking from the users perspective if such a huge file takes a lot of time to load and usage may be slower, hence less attractive.


Admin, I believe I need permissions to process it.

Thanks a lot

Hi Manuel,

Thanks for your message. I agree that this is an interesting shapefile and we should see how we can get it into the system. In the current form, this is a very large file, so I do would like to see if we can somehow reduce this. Firstly, if I understand from the description this map is available in a resolution of 1:500 000 and 1:2 000 000. This particular map, what resolution does it have? If it's the finest resolution then I recommend downloading the somewhat less detailed one.
Secondly, I see that there is almost 60 Mb (!) in the DBF file. That means there is a ton of meta data inside the table with properties. Could you inspect this information and remove all the columns that are not needed for our purposes, to see if we can this way reduce the size further? Let's see what we end up with.

In terms of how the file will appear: we have a way to crop the rivers and only show those that are in the city. So we should be able to present a much smaller version of the file. However, due to the large overhead data and resolution I still like to reduce the size before we process it. Let me know what you think.

Hello Paul, sorry for replying just now.

I want to let you know and Maria Gracia that I intend to finish this course, but these last two weeks were kind of crazy on work and Monday was a holiday. Even today I just finished now some meeting so I will try to study for my self the videos and any questions I will see if you can answer by e-mail or along the work.

I will look at this file and reduce the metadata, to see the size of it in the end. What is the recommended size for a file on this step, which regards to infrastructure and biophysical characteristics? I understand that maybe for some Stock and Flows layers there might be smaller files since they can be reduced to csv or xls, or am I wrong?

Hello Paul, how are you?

Back to MoC, slowly by slowly, after doing some other side community projects.

Look at the new file I uploaded (reduced the DBF to less than 10 Mb). I removed the flowdirections and some other features I believe were not relevant to our work.

Best regards,

Manuel Semedo

Hi Manuel, great to see you back in action again!

The reduction of the file is very good, this makes a big difference. I would also like to show you a change we made, which is very relevant. Please check out this video. In this case, I would suggest that you mark "The entire shapefile represents a single entity" as the option, because really this is not about individual streams and rivers but instead about a hydrological network. So if you select that, then the system can pick it up correctly.

Please feel free to move ahead in the processing work and let me know if you get stuck. At some point, the system will require an override so that it can process the file, due to the size, but you should be able to reach that point, and once you do, just give a shout and I'll mark it so it can finalize the processing.