Dev tools · alternatives · 2026
24 alternatives to Valid Place
Verify if coordinates belong to the polygons drawn on a map
Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Valid Place launched in 2016; newer entries below may have overtaken it.
- 1
To my knowledge, this is the first formally verified implementation of an intersection algorithm for polygons. The experience of working with AI agents on this project changed a lot with recent model releases, as I describe in the readme. Opus 4.8 is able to provide algorithm implementation with formal proof in one shot, whereas previous models required me to provide proof strategies in multiple steps. Trust in the correctness comes entirely from the Lean checker and human review of a small specification, not from the LLM. Also check out the web demo built around the verified core linked in…
Jun 2026 · github.com · its alternatives →
- 2
LocationChecker▲137You won’t have to worry the next time to visit a city
2024 · apps.apple.com · its alternatives →
- 3LW
Hi HN, I made a web game to practice country locations a while ago and HN liked it, so I thought I'd post my updated version as well. As for how the game works and feels, I'd really recommend you checking it out for yourself, it's free, no signup, no ads. The tech stack is Vue + ts + Tailwind/Daisy for the looks. The learning algorithm is a slight modification of the ts version of FSRS. If you have anything to add, it's open source as well (https://github.com/koljapluemer/learn-worldmap), although not well documented yet. In the end it's just a little sideproject,…
2025 · map.koljapluemer.com · its alternatives →
- 4
- 5IE
2017 · mjmdavis.com · its alternatives →
- 6
Get shown a place and try to guess where it is on the map
2024 · guesswhereyouare.com · its alternatives →
- 7
MapHub allows you to create, share and collaborate interactive maps online.
2016 · maphub.net · its alternatives →
- 8
- 9
2016 · kleemans.ch · its alternatives →
- 10
Scale-a-Tron▲74Draw a shape on a map, and compare with other areas.
2021 · stamen.github.io · its alternatives →
- 11
- 12
I wrote a tool in Python that finds the school district associated with any given street address in the United States. Here’s how it works: An address corresponds to a single point on the map. The U.S Census Bureau has a geocoder that converts an address to latitude and longitude coordinates. School district boundaries can be represented as polygons on the map. The National Center for Education Statistics (NECS) has geographic data on school district boundaries. Once we determine which polygon the point resides in, we know the school district.
2024 · github.com · its alternatives →
- 13
- 14
To my knowledge, this is the first formally verified implementation of a 3D constructive solid geometry (CSG) operation: mesh intersection, implemented in Lean 4 and verified against a concise specification that pins down the surface of the resulting mesh exactly and guarantees practical well-formedness conditions on the triangulation. This project is also an experiment in avoiding having to trust AI-generated code. A human reviewer only needs to read 93 lines of formal specification and run the Lean checker to certify the correctness of the kernel, skipping the intricate 1000+ lines of…
Jul 2026 · github.com · its alternatives →
- 15GA
Just a quick little feature I implemented over the weekend. TODO: Assure that polygons can be palindromic as well
2024 · altayakkus.dev · its alternatives →
- 16FP
Just a fun hack I did while bored over the weekend. My wife was busy shopping, it got me thinking that can VLMs solve the indoor location problem in a mall? Can I just show a VLM a map and an image and have it doa good enough job locating me? I hacked this P.O.C and it seems to work.
2025 · arjo129.github.io · its alternatives →
- 17
Guess locations based on the surroundings
2021 · geoguessr.com · its alternatives →
- 18IM
Hi HN, I built a little tool to help me get better at remembering country locations on the map: https://learn-worldmap.netlify.app/ It's made from plain HTML/CSS/JS, and not intended to make any money or anything. Just thought that maybe someone else may enjoy it. Also of course happy about any feedback! Cheerz.
2023 · learn-worldmap.netlify.app · its alternatives →
- 19
MapChecking▲71Suspicious of a politician's crowd size? Verify it with this
2017 · mapchecking.com · its alternatives →
- 20
- 21
Quetzly▲79Test, monitor, and visualize your location APIs in one place
Jan 2026 · quetzly.com · its alternatives →
- 22
For a game I'm developing I needed an easy way to create hotspot areas on images. So I hacked together a small tool to do so and before I knew it, I had created an entire app :-) It allows you to generate JSON or YAML from the coordinates you tack on the image. tack runs entirely in your browser, there is no server side component to it, so good in terms of privacy. Hope this is helpful.
May 2026 · tack.pics · its alternatives →
- 23
- 24
Interactive map of every disputed territory in the world
2016 · its alternatives →
Also compare
- Formally verified polygon intersection – Opus 4.8 oneshots, prev failed alternatives
- LocationChecker alternatives
- Learn where countries are on the world map with Spaced Repetition alternatives
- TimeDive alternatives
- Interactively explore different map projections alternatives
- Guess Where You Are alternatives
Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →