03 – How to generate tiles

Introduction #

In the following documentation we will explain how tiles are generated as well as the resources needed to generate them. For this we would need:

• Coordinates of the corners of the Dashboard floors, they are obtained here.
• Image file with our plants in high resolution.
• QGIS program installed.
• Windows computer with Ubuntu console or computer with Linux.

QGIS Process #

The process would be the process for generating Tiles:

• Download QGIS from the following link: https://www.qgis.org/en/site/forusers/download.html

• Go to Raster or Layer (depending on the version) -> Georeferencer in the top menu (it may be under Layer).

• Then go to Open Raster and load the high-definition map.

• Click on Select Point and enter the 4 corners of the Dashboard.

• To adjust these points correctly, you need to edit the table following this criterion:
  • Top-left point -> X origin = 0 // Y origin = 0
  • Top-right point -> X origin = width of the loaded image // Y origin = 0
  • Bottom-right point -> X origin = width of the loaded image // Y origin = negative height of the loaded image
  • Bottom-left point -> X origin = 0 // Y origin = negative height of the loaded image

• Go to Transformation Settings and set the following transformation:

• Save the points.

• Click on Start Georeferencing.

• Look for “Generate XYZ tiles” in the processing toolbox, fill in the following parameters and execute:

• Once generated, compress them using OptiPNG, for which you will need to have the Ubuntu console installed on Windows or do it on Linux.

Installation of Ubuntu console on Windows #

Install OptiPNG #

To install it, simply run these commands in the Ubuntu console:

sudo apt-get update

sudo apt-get install optipng

Once installed, use the following commands to navigate to the directory where the Tiles are saved:

cd .. → Takes you to the previous directory 

cd directoryname → Takes you to the specified directory (if it's a subfolder) 

ls → List of subfolders in the current directory

Compress images #

Once you reach the root of the zoom folder you want to compress, execute the following command (remember to run the Ubuntu console as an admin):

sudo optipng **/*.png

Once compressed, you can upload them to Situm.

Uploading tiles #

In order to upload the tiles, you need package them in a zip file. This zip must one folder per floor to which you want to associate the tiles. Each folder must be named using the ID of each of those floors:

Inside each folder, you will find the typical “zoom/x/y” structure of tile servers:

Then, you may upload them to Situm Dashboard in the Building edition dialog: