Galactic distribution of the ATLASGAL Top100 sample. The positions of the H ii regions, mid-infrared bright, mid-infrared weak and 70 μm weak sources are indicated by the blue, green, red, and yellow filled circles, respectively. The orange shaded area indicates the region of the Galactic plane covered by the ATLASGAL survey to a distance of 20 kpc, within which the survey is complete for compact clumps with masses >1000 M_⊙. The background image is a schematic of the Galactic disc as viewed from the Northern Galactic Pole (courtesy of NASA/JPL-Caltech/R. Hurt (SSC/Caltech)). The Sun is located at the apex of the wedge and is indicated by the ⊙ symbol. The smaller of the two cyan dot-dashed circles represents the locus of tangent points, while the larger circle traces the solar circle. The spiral arms are labeled in white and Galactic quadrants are given by the roman numerals in the corners of the image. The magenta line shows the innermost region toward the Galactic center where distances are not reliable.