Here Map Attributes v8 to v7 - Convert tileIds to tileXYs - here-api

Question

Currently, our application uses Here Map Attributes API v7 and the response looks like this
https://pde.api.here.com/1/index.json?app_id=&app_code=&layer=ROAD_GEOM_FCn&attributes=LINK_ID&values=17339738,17339811
{
"Layers":
[
{
"layer": "ROAD_GEOM_FC3",
"level": 11,
"tileXYs":
[
{
"x": 2000,
"y": 1611
},
{
"x": 2009,
"y": 1611
}
]
}
]
}
We're trying to migrate to new V8 API and having issues with translating the response model. In v8 the response returns tileIds (instead of tileXYs)
https://smap.hereapi.com/v8/maps/index.json?layer=ROAD_GEOM_FCn&attributes=LINK_ID&values=17339738,17339811&apiKey=
{
"Layers":
[
{
"layer": "ROAD_GEOM_FC3",
"level": 11,
"tileIDs":
[
6600656,
6600665
]
}
]
}
Is there a way I can convert tileIds into tileXYs similar to the legacy response?
I tried to convert lat and long from this API endpoint like in the docs but didn't work.
https://developer.here.com/documentation/content-map-attributes/dev_guide/topics/here-map-content.html
https://smap.hereapi.com/v8/maps/attributes.json?layers=ROAD_GEOM_FC3&in=tile:6600656&apikey=

Answer 1

First variant:
Calculates tileX and tileY out of a given tileId and a level
#param tileId - the tile id
#param level - the PDE layer level
#param tileXYLevel - this OUT parameter is filed with tileX, tileY and the level
*/
public void getTileXYLevel(long tileId, int level, int tileXYLevel[]) throws Exception
{
if (isStaticContent) {
tileXYLevel[0] = 0;
tileXYLevel[1] = 0;
tileXYLevel[2] = 0;
return;
}
int numTilesVertical = 1L << level;
int tileX = (int)(tileId % (2 * numTilesVertical));
if (tileX < 0 || tileX >= numTilesVertical * 2)
throw new Exception("Invalid tileX=" + tileX + " for level " + level + ", must be [0 ... " + (numTilesVertical * 2 - 1) + "]");
int tileY = (int)((tileId - tileX) / (2 * numTilesVertical));
if (tileY < 0 || tileY >= numTilesVertical)
throw new Exception("Invalid tileY=" + tileY + " for level " + level + ", must be [0 ... " + (numTilesVertical - 1) + "]");
tileXYLevel[0] = tileX;
tileXYLevel[1] = tileY;
tileXYLevel[2] = level;
}
Second variant:
Regarding this formulas:
tile size = 180° / 2^level [degree]
tileY = trunc((latitude + 90°) / tile size)
tileX = trunc((longitude + 180°) / tile size)
tileID = tileY * 2 * (2^level) + tileX
This is not possible. At least it is needed to know whether latitude or longitude then you can calculate tileX or tileY.
Better way is:
1.Request this https://smap.hereapi.com/v8/maps/attributes.json?layers=ROAD_GEOM_FC3&in=tile:6600656&apikey=
In fist Row of response you have:
Meta: {
layerName: "ROAD_GEOM_FC3",
tileId: 6600656,
level: 11,
mapRegion: "WEU",
mapRelease: "22125",
},
Rows: [
{
LINK_ID: "17339811",
LONG_HAUL: "N",
NAME: "B4304",
NAMES: "ENGBNB4304",
TUNNEL: "N",
BRIDGE: "N",
LAT: "5167314,16,9,10",
LON: "-417072,-9,-6,-9",
ZLEVEL: ",,,",
ELEVATION: ",,,",
TOPOLOGY_ID: "98996232",
START_OFFSET: "0",
}
Then you have from LAT, LON:
lat: 51.67314; lng: -4.17072
2.From above coordinate you calculate tileX and tileY, see please Javascript example:
var
degSize = 180 / Math.pow(2, level),
tileY = Math.floor((lat + 90) / degSize),
tileX = Math.floor((lng + 180) / degSize);
You know from response of https://smap.hereapi.com/v8/maps/index.json? that level is 11 (or you know it from "Meta" property)
After calculation we have tileX = 2000 and tileY = 1611