# LSPIV vs MARVLS

The clearest difference is ratings volume: MARVLS at 35 against LSPIV's 1. LSPIV's advantage is rating (5.0 vs 4.8). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

LSPIV holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: MARVLS has 35 ratings behind it against 1, so its average is the more settled of the two.

LSPIV ships an update every 13 months, MARVLS every 8 months. The most recent releases landed on October 22, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | LSPIV | MARVLS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/lspiv/id981387743/reviews)** | [4.8 (35 ratings)](https://appshunter.io/ios/app/marvls-physics-ii-e-and-m/id1610425856/reviews) |
| Number of ratings | 1 | **35** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 13 months | **Every 8 months** |
| Monetization | Free | Free |
| Size | 71 MB | 208 MB |
| Requires iOS | 11.0 | 11.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ryota Tsubaki](https://appshunter.io/developer/981387742) | [Michele McColgan](https://appshunter.io/developer/1532617986) |

## What reviewers say

### LSPIV

[App page](https://appshunter.io/ios/app/lspiv/id981387743)

This application enables large-scale particle image velocimetry (LSPIV) using a smartphone. It offers a non-intrusive method for measuring water surface velocity distribution in both field and lab settings. The app provides instant ortho-rectification of captured images without needing ground control points.

**Highlights:** Large-scale particle image velocimetry, Water surface velocity measurement, Non-intrusive velocimetry, Smartphone implementation, Instant ortho-rectification, No GCPs required

**Features:** macOS Compatibility

**In-app purchases:** none


### MARVLS

[App page](https://appshunter.io/ios/app/marvls-physics-ii-e-and-m/id1610425856)

Explore physics and math concepts with interactive augmented reality models. This app brings abstract ideas to life, allowing users to manipulate and understand complex topics through their phone. Requires a printable Merge Cube for an immersive learning experience.

**Highlights:** Augmented reality models, Interactive physics concepts, Merge Cube integration, Topic navigation, Model manipulation

**In-app purchases:** none


## Frequently asked questions

### Is LSPIV free?

LSPIV is free to download, with no in-app purchases.

### Is MARVLS free?

MARVLS is free to download, with no in-app purchases.

### Which has better reviews, LSPIV or MARVLS?

LSPIV is rated higher. LSPIV averages 5.0 out of 5 from 1 ratings, while MARVLS averages 4.8 from 35 ratings.

### Do LSPIV or MARVLS have ads?

Neither LSPIV nor MARVLS shows ads.

### Which is updated more often, LSPIV or MARVLS?

LSPIV ships an update every 13 months, and MARVLS every 8 months. Most recently, LSPIV was updated on October 22, 2026 and MARVLS on October 20, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*