[Xastir] Ordnance Survey (OSGB) "OS OpenMap Local"

Wed May 2 11:18:06 PDT 2018

Greetings Paul,
A few years back I stumbled on MAPC2MAPC. The author is from the UK and he has been helpful to me. I did buy the application. I didn't try to do what you need so I have no clue if it will work or not..
http://www.the-thorns.org.uk/mapping/

Perhaps an approach might be using something like openstreetmaps (OSM). I don't know what your original map(s) look like but as a roadmap, it isn't bad. It does use the "slippy" tile structure and you may end up with a lot of 256x256 pixel tiles.

One of the beauties of OSM is you can add information where it is needed. For instance, in my neighbor there is a river that was dammed. It now has a lake but the map did not mention the lake. I was able to define and add the lake long the river. Also, while hiking a trail, I will record it and upload the trail if it is not in the data set. 

https://wiki.openstreetmap.org/wiki/Main_Page
https://www.openstreetmap.org/search?query=london#map=11/51.5076/-0.1276

One complaint about using OSM is the sheer number of tiles and the space they use. A file structure using mbtiles might help. I don't see the file storage being a big issue today. I have 2 laptop hard drives (320GB each) that were pulled for reuse. One will become part of a file server this weekend using an Raspberry Pi and US to SATA adapter.
Mbtiles: https://www.mapbox.com/help/define-mbtiles/

Another complaint is the tiles cannot be gathered all at once. You could build your own tile server / rendering machine from the data set. I have not down this but know someone who has. I will speculate and suggest that maybe a large area could be downloaded from OSM as a single map. I have seen what looks like this action in different applications (e.g., Planeplotter and YAAC?).

OSM may not be quite what you desire. For instance, I really like the 7.5min maps we have in the US. These have been my maps of preference for hiking, etc.  There are options that give similar results using the OSM data. So in addition to the 7.5" maps, I have OSM tiles with contours and current data.
This is one example: https://www.thunderforest.com/maps/landscape/

You may be able to create something very close to your desires using MapBox.
https://www.mapbox.com/

There are tile usage policies.

I can't really tell you how Xastir will handle tiles since I don't use Xastir. I remember reading about someone doing some work with them a few years ago.

Good luck!

Best regards,
Fred N7FMH

-----Original Message-----
From: Xastir [mailto:xastir-bounces at lists.xastir.org] On Behalf Of Paul Kent
Sent: Tuesday, May 01, 2018 4:20 PM
To: xastir
Subject: [Xastir] Ordnance Survey (OSGB) "OS OpenMap Local"

Hello, probably my first post here (have used Xastir for years so may not be).

in the UK, the national mapping authority (OSGB) has a new open-source
map, called OS OpenMap Local, which I am attempting to use within
Xastir 2.0.4  on Raspberry Pi.

I was using online maps which were free but now have been pulled.
I downloaded and compiled from source, with all options included, but
I couldn't get git version to start compiling (that's not what I'm
posting about here).

the specific message from debug is below:
------
Load maps start
load_maps: Calling draw_map
draw_map: Searching for map driver
draw_map: Found map driver: tif: 3
map_visible, rejecting: map_min_y:61199181 > SE_corner_latitude:21669765
	map or object is below viewport
Load maps stop
------
I can read the GDAL data from the tif file:

=====
 gdalinfo SO83SE.tif
Driver: GTiff/GeoTIFF
Files: SO83SE.tif
Size is 5000, 5000
Coordinate System is:
PROJCS["OSGB 1936 / British National Grid",
    GEOGCS["OSGB 1936",
        DATUM["OSGB_1936",
            SPHEROID["Airy 1830",6377563.396,299.3249646000044,
                AUTHORITY["EPSG","7001"]],
            TOWGS84[446.448,-125.157,542.06,0.15,0.247,0.842,-20.489],
            AUTHORITY["EPSG","6277"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4277"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",49],
    PARAMETER["central_meridian",-2],
    PARAMETER["scale_factor",0.9996012717],
    PARAMETER["false_easting",400000],
    PARAMETER["false_northing",-100000],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    AUTHORITY["EPSG","27700"]]
Origin = (385000.000000000000000,235000.000000000000000)
Pixel Size = (1.000000000000000,-1.000000000000000)
Metadata:
  AREA_OR_POINT=Area
  TIFFTAG_COPYRIGHT=� Crown copyright and/or database right 2018 OS
  TIFFTAG_IMAGEDESCRIPTION=OS Open Map - Local - Full colour raster -
TILE SO83SE
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
  TIFFTAG_XRESOLUTION=254
  TIFFTAG_YRESOLUTION=254
Image Structure Metadata:
  COMPRESSION=LZW
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (  385000.000,  235000.000) (  2d13' 6.89"W, 52d 0'46.09"N)
Lower Left  (  385000.000,  230000.000) (  2d13' 6.11"W, 51d58' 4.24"N)
Upper Right (  390000.000,  235000.000) (  2d 8'44.60"W, 52d 0'46.49"N)
Lower Right (  390000.000,  230000.000) (  2d 8'44.07"W, 51d58' 4.64"N)
Center      (  387500.000,  232500.000) (  2d10'55.42"W, 51d59'25.38"N)
Band 1 Block=5000x32 Type=Byte, ColorInterp=Palette
  Color Table (RGB with 256 entries)
    0: 0,0,0,255
    1: 8,7,7,255
    2: 24,24,24,255
    3: 40,40,40,255
    4: 52,52,52,255
    5: 85,15,45,255
    6: 49,83,63,255
...
...
...
255: 255,255,255,255

=====
Any Idea why I'm getting  this error?
I'd rather not have to run a script to mangle each and every tile in
the set, as there will be hundreds

73 de Paul G0WXT
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