ところを見ると|ところをみると

Judging from ~ / seeing that ~. The speaker presents something they have observed as evidence and draws an inference or guess from it.

Used in both speech and writing to base a guess on something the speaker has actually noticed, usually another person's state or a situation. The main clause normally ends in an inference expression such as らしい, ようだ, にちがいない or だろう. Compared with ところから or ことから, it emphasizes that the evidence is something the speaker has directly observed.

• とみえる / とみえてN3「とみえる」is itself an inference and can end a sentence on its own; with 「とみえて」, the inference comes first and the evidence after — the opposite word order from 「ところを見ると」. It is fairly literary and can also be used to infer one's own state, and the two often combine as 「…ところを見ると、…とみえる」.
• ところからN2「ところから」has a strong written-style flavor; besides serving as a basis for judgment, it can also explain the origin of a name or a result arising from it, and the following clause states an objective result or judgment, not limited to conjecture. When attaching to a noun, only 「である」 can be used — not 「の」.
• からすると / からすればN2「からすると」attaches only to nouns, and its basis is not limited to concrete signs — it can also mean 'from someone's standpoint.' 「ところを見ると」attaches to the plain forms of verbs, adjectives, and the like, and draws a conjecture from concrete signs you see or hear.
• ことからN2「ことから」leans toward written style; besides explaining the origin of names, it can also introduce a judgment, decision, or result. 「ところを見ると」conjectures from signs noticed on the spot, and the following clause is usually a guess — the two are close only when 'making a judgment based on facts.'
• ようだN4「ようだ」goes at the end of the sentence and states the conclusion of the inference (it also has a simile use), while 「ところを見ると」goes in the first clause to present the basis for the guess. The two cannot be swapped, and they often combine as 「～ところを見ると、～ようだ」.
• どうやらN2「どうやら」is an adverb meaning 'it seems' within a sentence of conjecture and does not itself state the basis, whereas 「ところを見ると」follows the first clause and makes the basis explicit. The two cannot be interchanged but are often used together; 「どうやら」also has the sense of 'finally / just barely.'

ところを見ると attaches to the observed evidence, whereas とみえる/とみえて attaches to the inferred conclusion (e.g. 体調が悪いとみえる); ところから, ことから and からすると/からすれば also mark a basis for judgment but can cover general facts, reasons or viewpoints (ことから can even explain the origin of a name). ようだ is a sentence-final inference ending and どうやら an adverb of conjecture, and both often co-occur with ところを見ると rather than replacing it.