<div dir="ltr"><div>Hi,<br><br>Yes, I have ordered an ESP32 board (Inkplate 6plus) which I am planning to use as a portable selfcontained map-viewer (solar charged). My initial plan was to try using as close to "raw" data from sources as possible, to minimize hazzle with updating the maps. This would mean doing all processing on the device and send the image directly to the screen, but after playing around with gdal/qgis I have realised that plan might have been a bit too ambitious.</div><div><br></div><div>Thanks for your suggestions, I realise I have focused too much on the GeoPackage-part (a search that led me to gdal in the first place). I think the ideal for my usecase is some sort of vector format which I can dynamically filter on the device during rendering to cram as much info as possible into the 16 shades available on screen. I will research other vector formats and what suitable (C/C++) libraries and utilities are available.<br></div><div><br></div><div>As a last case fallback I guess X/Y/Z raster tiles rendered in a compressed 4bpp form would suffice, if vector processing is too much for the device.<br></div><div><br></div><div><br><div class="gmail_quote">On 14 April 2023 10:35:56 UTC, "Cainã K. Campos" <<a href="mailto:rupestre.campos@gmail.com" target="_blank">rupestre.campos@gmail.com</a>> wrote:<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr"><div>Hi Martin, <br></div><div><br></div><div>there are a few options but using gdal directly may not be so easy,<br></div><div>I'd love to hear how to do it using gdal only.<br></div><div>Just to understand better, some information on your setup would help,</div><div>like how do you plan to access those black n white tiles, over network or local only?<br> Machine and setup specifications, is it a rpi4, 3 0 or ESP32 or what? Spare parts to create a server and a client or just a single board?<br></div><div>I ask it because the process to read a vector and produce a tile may require some processing power.<br></div><div>As you said you are using Qgis, try it on server mode, where you can publish the maps you create on the local network. This way you setup styles as you create a map in qgis.<br></div><div>Other options out there for publishing vector data : <br></div><div><div>Spin a geoserver and set the style of the map layers, also you may combine two or more
in order to make a single request, create cache and more.<br></div></div><div>Using Postgres/postgis and pg_tileserv you may create vector tiles and render it on the client, or on a custom server middleware.<br></div><div>If you are going offline and your machine has lots of processing power, like a rpi4, just self-host those services on the machine and point services to localhost:port_number.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 13, 2023 at 6:16 PM Martin Häggström <<a href="mailto:cjmhaggstrom@gmail.com" target="_blank">cjmhaggstrom@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hello all,<br><br>I am trying to read vector GeoPackage files in order
to render a custom map suitable to display on a 3bpp e-ink screen (8
grayscales per pixel). I am a complete noob in anything related to GIS
and mapping and all terminology, but I have managed to use
GDALRasterizeLayers to burn (almost) all features of the vector layers
into a raster GTiff. However, I have no idea how or if I can apply any
sort of styling while using this procedure.<br><br>Using
GDALRasterizeLayers I get an image containing all the different features
on the map as specific pixel values, which I could color differently as
a post process, but I can not change _how_ the features are renderad in
the first place (different brush, stroke width etc). I have tried using
OGRFeature::SetStyleString() on the source layers, but it does not seem
to have any effect.<br><br>Using QGIS I can read the GeoPackages
together with a .qlr file to get a map that looks as it originally
should, and from there I can "Export map to image" and generate XYZ
tiles (I haven't gotten these to look exactly correct though), but I
would primarily like to find a way to programmatically render tiles on
the fly directly to my custom screen.<br><br><div>Am I using the correct
approach for creating a bitmap image from vector, or is rasterize meant
for other use cases? It seems most examples focus on data processing
rather than map rendering. I am unfamiliar with the terminology so I
worry I might be going the wrong direction entirely when searching for
the solution.</div><div><br></div><div>Best Regard,</div>Martin Häggström</div>
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