Latitude & langitude calculation

[dedenker]

My setup is a follow:
I pick a center location lat&lng (from google maps) and use that in the offline map downloader.
From there I select an area to download.

Then convert, upload and use the same lat&lng as starting point in on the device (round 4 inch).
This all works perfect!

But when I pick a new lat&lng, it will not take me to the correct location.
The (wrong) offset seems to increase by the zoom level.

I found this issue with using the add_marker function.

[0015]

@dedenker Sorry for being late. I found your issue while adding new content to Github. Thanks for reporting. I am currently investigating the new map_display_add_marker. I'll let you know when it's resolved. (Thanks for adding me on Reddit! I’ve been super busy lately, so I don’t always get a chance to check it. Sorry about the delay.)

[0015]

@dedenker I've added the map_display_add_marker function, which was used when creating Dragon Lader, to the map_tiles example. Please try this way to add additional marker.

void map_display_add_marker(double lat, double lon)
{
if (!map_handle) {
ESP_LOGE(TAG, "Map not initialized");
return;
}

// Check if GPS position is within current tiles
if (!map_tiles_is_gps_within_tiles(map_handle, lat, lon)) {
    ESP_LOGW(TAG, "GPS position outside current tiles, reloading map");
    map_display_load_location(lat, lon);
    return;
}

// Convert GPS to tile coordinates
double tile_x, tile_y;
map_tiles_gps_to_tile_xy(map_handle, lat, lon, &tile_x, &tile_y);

// Get current grid position (top-left tile)
int base_tile_x, base_tile_y;
map_tiles_get_position(map_handle, &base_tile_x, &base_tile_y);

// Calculate absolute pixel position of marker
int abs_px = (int)(tile_x * MAP_TILES_TILE_SIZE);
int abs_py = (int)(tile_y * MAP_TILES_TILE_SIZE);

// Calculate top-left pixel position of current tile grid
int top_left_px_x = base_tile_x * MAP_TILES_TILE_SIZE;
int top_left_px_y = base_tile_y * MAP_TILES_TILE_SIZE;

// Get scroll position if map is scrollable
lv_coord_t scroll_x = lv_obj_get_scroll_x(map_container);
lv_coord_t scroll_y = lv_obj_get_scroll_y(map_container);

// Calculate marker position relative to current view
int marker_x = abs_px - top_left_px_x - scroll_x - 5;  // -5 to center the 10px marker
int marker_y = abs_py - top_left_px_y - scroll_y - 5;

ESP_LOGI(TAG, "Marker calculation: tile_xy=(%.3f,%.3f) base=(%d,%d) abs_px=(%d,%d) scroll=(%d,%d) pixel=(%d,%d)",
         tile_x, tile_y, base_tile_x, base_tile_y, abs_px, abs_py, scroll_x, scroll_y, marker_x, marker_y);

// Check if marker is within visible bounds
int container_width = grid_cols * MAP_TILES_TILE_SIZE;
int container_height = grid_rows * MAP_TILES_TILE_SIZE;
if (marker_x < -10 || marker_x > container_width || marker_y < -10 || marker_y > container_height) {
    ESP_LOGW(TAG, "Marker at (%d, %d) is outside visible bounds (0,0) to (%d,%d)",
             marker_x, marker_y, container_width, container_height);
}

// Create or update marker object
static lv_obj_t* marker = NULL;
if (!marker) {
    marker = lv_obj_create(map_container);
    lv_obj_set_size(marker, 10, 10);
    lv_obj_set_style_bg_color(marker, lv_color_hex(0xFF0000), 0);
    lv_obj_set_style_radius(marker, 5, 0);
    lv_obj_set_style_border_width(marker, 1, 0);
    lv_obj_set_style_border_color(marker, lv_color_hex(0xFFFFFF), 0);
}

lv_obj_set_pos(marker, marker_x, marker_y);

ESP_LOGI(TAG, "GPS marker at (%.6f, %.6f) positioned at pixel (%d, %d)", 
         lat, lon, marker_x, marker_y);

}