Draw Direction Lines on a Floor Plan | House Center (Centroid), 8 Directions, 24 Mountains & Kimon Line
Load a floor plan image and tap to trace the outline of the house, and it automatically finds the area centroid (the center of the house) and draws direction lines from there. Choose from three divisions: 8 directions (45° each), Japanese kasō (house physiognomy) with 30° cardinal and 60° diagonal sectors, and the 24 mountains (15° each). Just align the red arrow with the plan’s north symbol to set the orientation, and correct the true-north/magnetic-north declination (westward) using regional guides. Place pins on rooms like the toilet or entrance to get a table of their direction, mountain, angle, and offset from the kimon line. The image with direction lines can be saved as a PNG, and images never leave your browser.
Tap places whose direction you want to know, like the toilet, entrance, or kitchen. Drag pins to move them.
Kimon & ura-kimon ranges
- Kimon (northeast, 艮)
- 22.5°–67.5°
- Ura-kimon (southwest, 坤)
- 202.5°–247.5°
- Kimon line (diagonal)
- 45° and 225° from north
Angles are clockwise with True north as 0°. Ranges for the 8-direction (45° each) division. Switch to kasō’s 60° diagonals under “Division”.
Share of floor area by direction (guide)
- N10.5%
- NE9.7%
- E19.4%
- SE9.3%
- S8.5%
- SW14.9%
- W15.1%
- NW12.6%
The share of floor within each direction’s range seen from the center, counted using 45°-each ranges. A direction with very little suggests that side is recessed.
Directions of checked locations
| Location | Directions | 24 mountains | Angle | Nearby line |
|---|---|---|---|---|
| SWUra-kimon | 申 | 238.6° | — | |
| NEKimon | 寅 | 60.6° | — |
Direction uses the 8 directions (45° each) division, and angle is the bearing from the center. Within 7.5° of a cardinal or diagonal line, the nearby line and angle difference are shown (yellow within 3°).
ABOUT
About Draw Direction Lines on a Floor Plan | House Center (Centroid), 8 Directions, 24 Mountains & Kimon Line
The floor plan direction lines tool overlays direction lines drawn from the center of the house onto a floor plan image. When reading directions in Japanese kasō (house physiognomy) or feng shui, you first determine the “center of the house”, then align north and divide into 8 or 24 directions, but for L- or U-shaped houses it’s easy to get stuck on how to find the center. This tool calculates the area centroid (the center by the “centroid method” in kasō) automatically just by tapping around the outline. You can also switch to the intersection of the bounding rectangle’s diagonals, or place the center by hand. Align the red arrow with the plan’s north symbol to set the orientation, and correct the difference between true north and magnetic north (in Japan, magnetic north is about 5–10° west) using regional guides. Divisions are 8 directions (45° each), kasō with 30° cardinal and 60° diagonal sectors, and the 24 mountains (15° each), and you can also draw the cardinal and diagonal (kimon) lines. Place pins on the toilet, entrance, kitchen, and so on to list their direction, mountain, angle, and offset from the kimon line, and save the plan with direction lines as a PNG.
How to use Draw Direction Lines on a Floor Plan | House Center (Centroid), 8 Directions, 24 Mountains & Kimon Line
- 1Choose a floor plan photo or screenshot with “Load a floor plan image” (you can try the sample plan first)
- 2In “① Trace the outline”, tap the corners of the exterior walls in order, then tap the first point again to close
- 3In “② Align north”, drag the red arrow to match the direction of the plan’s north symbol (choose true or magnetic north here too)
- 4In “③ Check the center”, choose how to find the center: centroid, bounding rectangle, or manual
- 5Under “Division”, choose 8 directions (45°), kasō (30°/60°), or the 24 mountains
- 6In “④ Check locations”, tap the toilet, entrance, and so on to check their direction and angle
- 7Save as a PNG with “Save image with direction lines” and share it with family or your designer
Great for
- Check whether the toilet, entrance, or kitchen falls on the kimon or ura-kimon in a new build or remodel plan
- Find the center (centroid) of an L- or U-shaped house without cutting out cardboard
- Compare how directions change between kasō’s 30°/60° and feng shui’s 45° per direction
- Check the directions of rooms and wet areas on a rental or used home’s floor plan before a viewing
- Draw lines correcting the difference between north measured with a compass (magnetic) and north on the plan (true)
- Write down which rooms fall in which of the 24 mountains
- Use a floor plan image with direction lines in meetings with family or a home builder
Good to know
- The house center is calculated as the centroid of the area enclosed by the outline. In kasō, areas not enclosed by walls, such as verandas, balconies, wood decks, and carports, are generally excluded from the outline. For two-story houses, the center is usually found from the first-floor outline. Methods differ by school, so follow any rules from the expert or company you’re consulting.
- For extreme U- or L-shaped houses, the centroid may fall outside the building. A warning appears in that case, so compare it with the bounding-rectangle center or a manual center.
- How directions are divided varies by school. Feng shui and directional studies often divide 8 directions at 45° each, while kasō often uses 30° for north, east, south, and west and 60° for the four diagonals such as northeast. The 24 mountains are 15° each, with three mountains making one direction (45°).
- In Japan, compass north (magnetic north) is about 5–10° west of map north (true north) (westward declination). As a guide, declination is about 9–10° in Hokkaido, 7–8° on Honshu, and 5° in Okinawa. Kasō often uses magnetic north while maps and design drawings use true north, so you can choose which north to draw lines from. Regional values are guides; check the exact value with the Geospatial Information Authority of Japan’s geomagnetic data.
- The kimon (demon gate) is the northeast, and the ura-kimon (back demon gate) is the southwest. The diagonal line connecting northeast and southwest is called the kimon line and is shown in red.
- The share of floor area by direction is a rough value from adding up, in fine angular steps, how much floor falls within each direction’s range seen from the center. It isn’t a judgment of protrusions or recesses (hari/kake) itself.
- Kasō and feng shui are traditional ideas about dwellings and have not been scientifically verified. This tool is for drawing lines quickly and accurately and doesn’t judge good or bad fortune.
- Loaded images are only scaled down in your browser and are not sent to a server.
Questions this tool answers
Use Draw Direction Lines on a Floor Plan | House Center (Centroid), 8 Directions, 24 Mountains & Kimon Line for searches like these:
- I want to draw direction lines on a floor plan
- I want to know how to find the center (centroid) of an L-shaped house
- I want to check whether the toilet or entrance falls on the kimon or ura-kimon
- I want to view directions with kasō’s 30°/60° division
- I want to overlay the 24 directions (24 mountains) on a floor plan
- I want to correct for the difference between true north and magnetic north
- I want to know how to draw the cardinal and diagonal lines
- I want to save a floor plan with direction lines as an image
FAQ
- How do I find the center of the house?
- For a rectangular house, the center is where the diagonals cross. For L- or U-shaped houses, the “centroid method” is commonly used: trace the house shape onto cardboard, cut it out, and take the point where it balances on a pin as the center. This tool calculates that centroid just by tracing the outline.
- Should I use true north or magnetic north?
- It depends on the approach. Kasō often uses magnetic north measured with a compass, while north symbols on maps and design drawings are usually true north. If you align the plan’s north symbol as true north and set “north for drawing lines” to magnetic north, the lines rotate counterclockwise by the declination to give magnetic-north direction lines.
- What’s the difference between 45° per direction and kasō’s 30° and 60°?
- Dividing all 8 directions into 45° each is common in feng shui and directional studies. In kasō, north, east, south, and west are 30° and the four diagonals (northeast, southeast, southwest, northwest) are 60°. Because the diagonals are wider, the areas falling on the kimon (northeast) and ura-kimon (southwest) are wider too.
- What is the kimon line?
- It’s the line drawn from the house center toward the northeast (kimon) and southwest (ura-kimon), one of the diagonal lines. In kasō, it’s sometimes said that toilets, entrances, and wet areas shouldn’t be placed on this line. This tool shows it as a red dash-dot line and also shows how many degrees a pinned location is from the line.
- How are the 24 mountains (24 directions) divided?
- 360° is divided into 24 sectors of 15° each, running clockwise from 子 (north): 子・癸・丑・艮・寅・甲・卯・乙・辰・巽・巳・丙・午・丁・未・坤・申・庚・酉・辛・戌・乾・亥・壬. Three mountains make one of the 8 directions (45°); for example, northeast is 丑・艮・寅.
- Can I use a photo of a floor plan taken with my phone?
- Yes. You can load JPEG, PNG, WebP, and other images. Photos taken at an angle distort the shape and shift the center and angles, so shoot from directly above as much as possible, or for a PDF floor plan, take a screenshot first.
- Is the floor plan I load sent anywhere?
- No. Scaling the image, calculating the center, drawing direction lines, and saving the PNG all happen in your browser.
Special Thanks