Author Topic: External vector maps format?  (Read 382 times)

Offline Steve_

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External vector maps format?
« on: January 18, 2022, 23:11:33 »
Hello,

Apologies if this is obvious or answered elsewhere.

I'm trying to find out specifically what format I can import external vector maps in, I found a help page about it (https://docs.locusmap.eu/doku.php?id=manual:user_guide:maps_external)... but got a bit confused, as when looking for documentation for the *.map mentioned there seemed to be multiple formats using that extension.

What I'd like to do is use an overlay of the public access areas in New Zealand (example https://maps.walkingaccess.govt.nz/Viewer/?map=b1d1e76a6c754d11b3f3fd9dfce1eb12&extent=1023074.4266%2C4823457.503%2C1626009.7057%2C5124313.6464%2C2193). This is a govt project aimed at providing maps for access to public areas in NZ, not just national parks but paper roads and the like that allow access to remote areas (much of the data is sourced directly from govt geographic agency LINZ).

Currently I have the data in shapefiles and have been exporting them in raster MBtiles with QGIS, however this makes for huge files that are incredibly slow to export on my hamster powered PC. oh and I'm using LM4.


Any pointers appreciated!

 

Offline michaelbechtold

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Re: External vector maps format?
« Reply #1 on: January 18, 2022, 23:37:50 »
Hi Steve,
in the context of Locus et.al. .map indicates a VECTOR map following Mapsforge format definition.
Such maps are crappy up to zoom level 10 or so, yet highly efficient when it comes to storage requirements, because the rendering is done on the dvice. Up to ZL 22 if you want.
Your description tells that you are dealing with RASTER maps. They are "costly" (size) for higher (detail) zoom levels.
The map your second link is pointing to is a raster map, i.e. an array on images.
I am sure that NZ has all data that you see as discrete value sets in a huge database, which is the source for the ArcGIS rendering.
If you get access to this data AND they can provide that in OpenStreetMap format, then you win. Even if they would give you a text export and their data model, you could convert to OSM, so you can use the OSM tools to build VECTOR maps.
They would be easy to digest for Locus, but need real processing power (and knowledge) to produce ...
 
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Offline Steve_

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Re: External vector maps format?
« Reply #2 on: January 19, 2022, 00:36:39 »
Thanks for your reply Michael,

I might have mislead you a bit with the 2nd link, I intended it as a graphical example of what I hope to achieve but now I realise that isn't very clear.

When looking at the link, I currently have the topo basemap in Locus as raster tiles, its the items in the legend (Reserves, road parcels ect) that I would like to add to Locus as a vector overlay (level 8ish to 18). Your correct that this data is available, I have downloaded it in vector shapefiles but without knowing how to covert it into a vector format Locus is able to work with I was forced to render into raster mbtiles using QGIS... which works but as you say is incredibly costly in terms size (and processing time)!

The data is available in multiple GIS formats (shp, sqlite, mapinfo, csv) but OSM doesn't seem to be directly available. From a very brief search transformation to OSM in QGIS/ArcGIS doesn't seem particularly good so I'll do a little bit of playing around with a dedicated OSM editor, but that area is completely new to me and I'm a bit concerned about the processing power requirements you mentioned; is it likely to be any slower than rendering mbtiles from a shapefile ect? and lastly are any starting formats more efficient than others ie shapefile vs sqlite?

This is likely way over my head but new is always interesting!







 

Offline michaelbechtold

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Re: External vector maps format?
« Reply #3 on: January 19, 2022, 01:44:56 »
OK, Steve, that fixes the starting point and the target ;-)
If I now understand correctly, you may get a CSV with maybe 1m (what is the actual number, pls. ?) entries with points (also ways and areas?) of interest that shall be overlaid. While you take another, existing map as base.
osmosis with mapwriter plugin can produce MF vector .map files.
So the jobs ahead are:
- convert your cover into a .osm file (XML) - pure text processing. Complexity of transformation depends on the type of objects you need. Points are pretty trivial, ways and areas need more thoughts.
- built a theme file and set of icons for rendering
I would imagine you are not the first trying this. So this transformation might be available already.
If it is only about POIs, then using KML directly would spare you buildings any maps. But only transform your csv to KML.
Cheers
Michael