Creating your own background map tile cache
In our last webinar the issue of the background tile cache came up. One question was would it be possible to have the tile cache on a thumb drive so that it could easily be moved to another computer. Currently if you go to the tools menu in Depiction and select settings and then the advanced tab.
You will see a display that shows the default location of the tile cache. Currently you can not change this field and you would need to do this in order to place the tile cache in a different location such as a thumb drive. We are exploring the possibility of letting you update this setting to the location of your choice.
If you are unfamiliar with the tile cache let me explain its use. When you are viewing your story in Depiction the back ground map source can be a map or an aerial image. Depending on which you have chosen the program goes out to the internet and finds the desired image tiles for that location and zoom level you have chosen. When it finds them it stores them on your disk in the directory specified in the settings above. However, before Depiction goes to the internet to look for a particular tile or tiles it first looks in the cache directory to see if the tile is already there. If it is then Depiction takes the tile from there and doesn’t go to the internet. The benefit of this is speed and also if the internet is down it is still possible to display the background tiles. The downside of this is that if the map tile has been updated then Depiction will continue to display the old tile. You might particularly notice this if you happen to update an Open Street Map yourself and then don’t see the change you made. To get around this on the Basic Settings screen there is a check box to Overwrite existing cache with new. If you check this box then Depiction will ignore the cache and go directly to the internet. Normally you would want to keep this box unchecked.
So knowing how depiction works using the cached files it would be possible to create your own cached tiles from a map source other than those provided by Depiction. We have one customer in Germany that did just that. He has written a paper on how he achieved this. It is fairly advanced but with his permission I am sharing it with those of you that have the skill set and maybe inclined to attempt this. You can find the document here.
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