How to Draw a Site Analysis Diagram — Order, Principles, and Automation

2026-08-26 · sitedia guide

The first page of almost every design report is site analysis. And almost every time, the hard part is not the drawing — it is deciding what to show and how far out to go. This is a working method: the order to do it in, the principles worth keeping, and the parts you should stop doing by hand.

Site inventory is not site analysis

These get conflated constantly, and the conflation is why so many analysis pages say nothing.

Site inventory is the collection of facts. Building footprints, land use, year built, street hierarchy, transit, topography, open space. It is verifiable and it has a source.

Site analysis is the argument you build on top of those facts. “The block grain west of the site is fine-grained pre-war fabric; east of the avenue it is superblock. The design has to negotiate that seam.” That sentence is analysis. The two maps under it are inventory.

A page of beautifully drawn inventory with no argument is decoration. An argument with no inventory under it is an opinion. You need both, and they are produced by different work — one by data, one by you.

Practically: get the inventory drawn fast and correctly, then spend your time on the argument. Most people do the reverse, which is why the argument ends up being written in the last hour.

Pick the radius before you pick the drawings

Radius is the single decision that determines whether your analysis reads. Too tight and there is no context; too wide and the site disappears.

American planning already has good defaults, and they are about walking:

RadiusWhat it capturesUse it for
500–660 ft The block and its immediate neighbors Single-site studies, infill, massing context, streetwall analysis
¼ mile (1,320 ft) A five-minute walk — the classic pedestrian shed Ground-floor use, walkability, everyday amenity
½ mile (2,640 ft) A ten-minute walk — the standard transit catchment TOD studies, station-area planning, district character
1 mile District scale, multiple neighborhoods Master planning, large-site framework, market context

Two rules that save rework. First, use the same radius across the whole set. If land use is drawn at ¼ mile and transit at ½ mile, the reader cannot overlay them mentally and the comparison is lost. Second, state the radius on the page. A diagram without a stated radius and scale bar is not evidence.

Why the circular frame

The circle is not a style choice. A radius is a statement about distance from a point, and a circle is the honest shape of that statement. A rectangle implies a boundary that does not exist, and it makes the corners — the parts furthest from your site — visually loudest.

The circle also solves comparison. Twelve circles of identical diameter can be laid on a page and read as one system: the eye holds the frame constant and sees only what changes between them. That is the entire reason multi-panel site analysis works.

Use a rectangle when the site itself is strongly linear — a waterfront strip, a rail corridor — and a circle would waste half the frame on water or nothing. Then set the dimensions explicitly (say 2,000 × 1,200 ft) rather than cropping by eye, so the scale stays stated.

The order that works

  1. Fix the site and radius. Everything downstream inherits them.
  2. Draw the ground first — terrain, water, green space. These are the slowest things to change and they explain why the city sits the way it does.
  3. Then the movement — streets by hierarchy, transit stops. This is the armature the fabric hangs on.
  4. Then the fabric — buildings, by use, by age, by height. Three readings of the same footprints, and the comparison between them is where most of the insight lives.
  5. Then the derived reads — density, block grain. These are interpretations of the fabric, so they belong after it.
  6. Aerial last, as a control. Put the photo next to your diagrams and check that they agree with the world. This catches data errors that look fine in the abstract.

Color and legend rules

One variable per panel. If a drawing is colored by use, height must not also be encoded. Two variables in one frame is a chart nobody can read.

Keep the base gray identical across panels. The context should be the same value everywhere so the reader's eye locks onto the one thing that changes. This is what makes a set feel like a set.

Legends come from the drawing, not from a template. If a category is not present in this radius, it should not be in the legend. A legend listing categories that do not appear teaches the reader to distrust it.

Say what is unknown. Roughly a third of NYC building footprints have no matching tax lot, so no year built. The honest move is a distinct “Unknown” color, not omission and not a guess. A drawing that hides its gaps is worse than one that shows them.

Stop tracing buildings

Here is the part worth being blunt about. Tracing building footprints in Illustrator and coloring them by use is between one and three hours per drawing, and it is entirely reproducible from open data. Footprints, heights, year built, land use, streets, transit, terrain — all published, all current, all free.

The work that is actually yours is the argument, the framing, the choice of what to compare. The tracing is not craft; it is transcription. When the site moves — and it always moves — transcription is the part you have to redo.

That is what sitedia does: you give it an address and a radius, and it draws the inventory at a fixed scale in a consistent frame, then hands you SVG (fully layered for Illustrator), DXF for CAD, and 3D for Rhino or SketchUp. What you do with the argument is still up to you.

Next: What the 12 panels show and how to read them →
← Back to sitedia · 한국어