The goal is to be able to download a real-world height map, import it into Unreal as a landscape, then draw roads on that landscape based off the GeoJSON file coordinates for that road.
I use this program to select a tile, create a height map, and download the GeoJSON for that selected tile. https://terrain.justgeektechs.com/#/
Current work in progress but coordinates are not coming out correctly.
Selected tile from above application.
So, this tile has just one road as it's feature.
GeoJSON long/lat coordinates corresponding to road.
[
{
"geometry": {
"type": "LineString",
"coordinates": [
[
-80.28769165277481,
26.931559068024825
],
[
-80.28771847486496,
26.94196560632824
]
]
},
"type": "Feature",
"properties": {
"iso_3166_1": "US",
"len": 4540,
"iso_3166_2": "US-FL",
"class": "secondary",
"type": "secondary",
"structure": "none",
"oneway": "false",
"name": "Pratt Whitney Rd",
"name_script": "Latin",
"shield_text_color": "black",
"ref": "711",
"reflen": 3,
"shield": "default"
},
"id": 112027551,
"layer": {
"id": "road-secondary-tertiary",
"type": "line",
"source": "composite",
"source-layer": "road",
"metadata": {
"mapbox:group": "1444855786460.0557"
},
"filter": [
"all",
[
"match",
[
"get",
"class"
],
[
"secondary",
"tertiary"
],
true,
false
],
[
"match",
[
"get",
"structure"
],
[
"none",
"ford"
],
true,
false
],
[
"==",
[
"geometry-type"
],
"LineString"
]
],
"layout": {
"line-cap": "round",
"line-join": "round"
},
"paint": {
"line-width": 8.693865073365155,
"line-color": {
"r": 1,
"g": 1,
"b": 1,
"a": 1
}
}
},
"source": "composite",
"sourceLayer": "road",
"state": {}
}
]
Sixteen-bit height map for this selected tile
The height map imports correctly to create a landscape in Unreal. Now my problem is getting the correct UE coordinates to create the road.
What I have so far in blueprints. I am using the new Geo Referencing System in UE 4.27 for the conversion.
https://blueprintue.com/blueprint/mdy1ytsa/
The long/lat pins are the data from the above GeoJSON coordinates
This is the resulting data after trying to convert the GeoJSON coordinates.
road-secondary-tertiary Latitude=26.93155861° Longitude=-80.28768921° Altitude=0.00m
long/lat converted to EFEC Cartesian coordinate
x = 959964.491
y = -5608767.070
z = 2871456.565
I am not sure why height is not 0 since that is a static value I am providing.
These coordinates do not match up with the height map. I am not sure what I am doing wrong.
Notes: GeoJSON coordinates are in (WGS 84) datum, with longitude and latitude units of decimal degrees.
Mapbox -- apps are visually rendered in the Web Mercator Projection (EPSG:3857)
Mapbox -- to pass data to show on these maps, either as a Marker or GeoJSON layer then that data must be passed as WGS 84 LL.
Unreal Georeferencing System doc.
https://docs.unrealengine.com/4.27/en-US/BuildingWorlds/Georeferencing/
Per doc Unreal supports this conversion as shown in link from doc to http://epsg.io/transform#s_srs=3857&t_srs=4326
