I am tinkering with file which has GeoJSON data of states but stored as a variable in JS.
Here is the file http://leafletjs.com/examples/us-states.js
However I am now using Topojson and reading the documentation https://github.com/mbostock/topojson/wiki/API-Reference
topojson.feature(topology, object) converts GeoJSON to Topojson.
However is there a way that I can store the Topojson format in JS format beforehand like I was doing for Geojson and then convert to GeoJSON calling some function?
Any help will be appreciated!
TopoJSON has a server and clientside API. Serverside (commandline) is for turning GeoJSON (and other formats, shp etc) into a smaller format called TopoJSON. Clientside API turns TopoJSON back into GeoJSON.
The TopoJSON client API supports converting TopoJSON objects back into GeoJSON for use in a web browser. This functionality is provided by topojson.js
Ofcourse you can edit TopoJSON files, just as well as you can edit GeoJSON files. They are both subsets of JSON. Javascript Object Notation.
JSON, (canonically pronounced /ˈdʒeɪsən/ jay-sən;[1] sometimes JavaScript Object Notation), is an open standard format that uses human-readable text to transmit data objects consisting of attribute–value pairs. It is the primary data format used for asynchronous browser/server communication (AJAJ), largely replacing XML (used by AJAX).
You can edit Geo just as well as Topo, it's just text.
Server: https://github.com/mbostock/topojson/wiki/API-Reference#server-api
Client: https://github.com/mbostock/topojson/wiki/API-Reference#client-api
Related
I am currently trying to read the files of an RDF4J triplestore from the universAAL platform and put them into an InfluxDB to merge the data from different smart living systems.
However, I have noticed that the individual index files of the Native repository are encrypted/unreadable (See image below).
Is there any experience from the community on how to get human readable content out of the RDF4J files (namespace, triples.prop, triples-cosp, triples-posc, triples-spoc, values.hash, values.dat, values.id) and merge them into another database?
The documentation of RDF4J did not help me here, so I could not create a decent export.
Encrypted File from Triplestore
The files are not encrypted, they're simply a binary format, optimized for efficient storage and retrieval, used by RDF4J's Native Store database implementation. They're not meant for direct manipulation.
The easiest way to convert them to readable RDF is to spin up a Native Store on top of them and then use the RDF4J API to query/export its data. Assuming you have a complete set of data files it should be as simple as something like this:
Repository rep = new SailRepository(new NativeStore(new File("/path/to/datafiles/");
try(RepositoryConnection conn = rep.getConnection()) {
conn.export(Rio.createWriter(RDFFormat.TURTLE, System.out));
}
finally {
rep.shutDown();
}
Obviously, replace System.out with a FileOutputstream if you want to write the data to file rather than the console. And change RDFFormat.TURTLE to something else if you want a different syntax format.
I'm trying to implement mapbox offline in my flutter application... until now I'm using the repository https://github.com/mapbox/mapbox-gl-native to get the map but this map comes in format *.db which is a SQLite format.
Now if I want to use that map (in format .db) in flutter I found the package https://github.com/tobrun/flutter-mapbox-gl where it has an instructions for loading the map (.db) ...
Now, that library is so basic .. I can't do more things like put markers or anything else.. that's why I'm trying to use the other library which is more common in fluter and is called 'flutter_map' and it has a way to load offline maps but the problem here is that I need '{x}{y}{z}.png' that's an image format.
Finally my question is: How can I pass from my map (.db) to that format ({x}{y}{z}.png) ??? or maybe ... how to convert (.db) to (*.mbtiles) ?? cause the last one is more common.
Thanks again!
Mapbox offers the Raster Tiles API which will serve map tiles in ({x}{y}{z}.png) format. https://docs.mapbox.com/api/maps/#raster-tiles These images will be satellite imagery though.
Mapbox also offers the Vector Tiles API which serves map tiles in .mvt format.
https://docs.mapbox.com/api/maps/#vector-tiles
Conversion to .mbtiles
You can convert .mvt tiles to geoJSON using this converter.
Use Mapbox Tippecanoe to convert from geoJSON to .mbtiles
I'm trying to create a web service in PHP that can deliver an SVG with reference to a PNG raster image. Both the data for the SVG as well as the binary PNG image come from a MySQL database on the server.
Option A: Encode the PNG data in base-64 and embed it directly in the SVG, such as:
<image xlink:href="data:image/png;base64,..."/>
Concerns: 30% heavier load than loading it as pure binary and noticeable delay when loading it with Postman (or is this just because of Postman).
Option B: Call the PNG data as binary and save it as a file on the file system, then call the SVG file, which would then reference the physical PNG file.
Concerns: Involvement of the file system (which implies I need to start managing physical files, expiration dates etc).
Is there perhaps another way that an SVG can reference the binary data on the fly without it having to be on the file system?
To accomplish something similar (in my case sending data for SVGs with additional data about each file as binary files, which are much smaller than sending xml, text, or json) - I use CBOR. In my case, I compress the SVG using LZString compression first, and add this along with additional data attributes to a JSON object. Then I convert the JSON object to CBOR. I think CBOR can handle your base 64 data without any need for conversion - more information about it is here: cbor.io
I found a PHP library for CBOR here: https://github.com/2tvenom/CBOREncode
This may not be the way to go at all for you, but I thought I'd throw it out there just in case.
I need to export a Domino document with RTF (images, tables, etc) to MS.Word in background mode or via Web. I have tried with POI4Xpages but I don't know how to export it.
You need to write your POI document to an output stream. This could be a fileOutputStream or the response. When using the response you need to set the header to reflect the file type. Check for XAgent for a sample how to do that. See: https://www.wissel.net/blog/2008/12/xagents-web-agents-xpages-style.html
*.pbf("Protocolbuffer Binary Format") is primarily intended as an alternative to the XML format.
There are two formats of *.osm.pbf and *.vector.pbf. What tools can I use to open these files? (I know JOSM can open *.osm.pbf files, but it can't open *.vector.pbf files.)
If I want to write own *.vector.pbf files in Mapbox, how do I work for that?
Thanks!
Regarding question #2, extracting PBF data
Using GDAL's ogr2ogr is the easiest method (I found).
Given a file named 1583.vector.pbf decode it to a, for example, shapefile (folder) named output:
# cmd show prog. output format output name input name
ogr2ogr -progress -f "ESRI Shapefile" output 1583.vector.pbf
Regarding question #3, creating PBF data
Use the same command as above but swap the input/outputs and output format:
# example source: https://gdal.org/drivers/vector/mvt.html
ogr2ogr -f MVT mytileset source.gpkg -dsco MAXZOOM=10
The Vector tiles used by Mapbox are serialized as Protocol Buffers.
Protocol Buffers allow you to efficiently compress the vector data inside the tile.
The Mapbox Tile Specification is available on github.
Esri has also adopted the same specification for their products.
You can find a list of parsers, renderers & CLI utilities here: https://github.com/mapbox/awesome-vector-tiles
In the common scenario, you can use mapbox-gl-js to render the vector tiles on the client. To generate vector tiles, you can use Mapbox Studio. This will require uploading your data online in the Studio. You can also use Mapbox Studio Classic (the older version) to generate the tiles locally.
Internally, Mapbox Studio uses the tilelive API, so you can programatically generate the tiles. In the list above there are other good alternatives as well.