# GDFF vs 水文水资源

The clearest difference is iOS requirement: 水文水资源 at 8.0 against GDFF's 10.0. 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.

GDFF ships an update every 3 weeks, 水文水资源 fortnightly. Both last shipped on October 7, 2026.

## The numbers

| Metric | GDFF | 水文水资源 |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Fortnightly** |
| Monetization | Free | — |
| Size | 41 MB | 32 MB |
| Requires iOS | 10.0 | **8.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [松林 赵](https://appshunter.io/developer/596658260) | [武汉海昌信息技术有限公司](https://appshunter.io/developer/1050059214) |

## What reviewers say

### GDFF

[App page](https://appshunter.io/ios/app/gdff/id1468415725)

This professional-grade sonar device connects to your smartphone to provide real-time underwater data. It maps depth, temperature, terrain, and fish density up to 500 meters away and 40 meters deep.

**Highlights:** Real-time sonar technology, Underwater mapping (depth, temp, terrain), Fish density and size detection, 500m signal range, 40m maximum depth, Adjustable gain and multiple modes

**Features:** macOS Compatibility

**In-app purchases:** none


### 水文水资源

[App page](https://appshunter.io/ios/app/id6448164950)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is GDFF free?

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

### Is 水文水资源 free?

水文水资源 is free to download, with no in-app purchases.

### Do GDFF or 水文水资源 have ads?

Neither GDFF nor 水文水资源 shows ads.

### Which is updated more often, GDFF or 水文水资源?

GDFF ships an update every 3 weeks, and 水文水资源 fortnightly. Most recently, GDFF was updated on October 7, 2026 and 水文水资源 on October 7, 2026.

---

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