MalaGIS

Sharing GIS Technologies, Resources and News.

In a previous article titled "Introducing GlobalBuildingAtlas: A Global Building Height Dataset ", I shared a global building dataset that includes height information. However, some readers noted concerns about its data quality. Therefore, I would like to share two other global building footprint datasets I discovered while working on CIM-related projects: one from Microsoft (open-source) and another from Google. Both are products of major tech companies, and their usefulness can be evaluated through testing.

Microsoft GlobalMLBuildingFootprints

Microsoft's GlobalMLBuildingFootprints open-source repository provides a global building footprint dataset. It detects approximately 1.4 billion buildings from multi-source Bing Maps imagery (2014–2024) and is freely available under the ODbL license. The data is provided in row-separated GeoJSON format (with a .csv.gz extension) using the EPSG:4326 coordinate system and includes attributes such as estimated height and confidence scores.

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A few days ago, while casually browsing, I heard experts in a group chat mention that NVIDIA has officially opened access to the GLM-4.7 and minimax-m2.1 models for free use. For someone like me, who even refuses to pay a 10 RMB repositioning fee for shared bikes, this immediately caught my attention! After a day of intermittent practical testing for GIS documentation writing and GIS development, while these models aren't as good as top-tier paid ones yet, they are quite adequate for daily GIS tasks. If you're currently on a tight budget and your daily GIS development work isn't too complex, you might want to give them a try. Given the current GIS market and economic climate, every bit of savings helps.

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In recent years, terms featuring the word "cloud" have become incredibly popular, from public cloud and private cloud to cloud-native, cloud-edge integration, and even national land cloud, planning cloud, etc. It seems almost every industry is moving to the cloud. But have you ever wondered, when we talk about so-called "cloud" data, are those streams of 1s and 0s literally traveling through the sky from a physical perspective?

Actually, no. In fact, over 90% of global international data traffic is transmitted through cables lying in the dark depths of the ocean. From the short video you just watched, to cross-border financial transactions, and even the answers you get from Gemini or ChatGPT, are all exchanged via lengthy submarine cables. But where exactly are they laid? Which countries are international communication hubs? How do different cables differ in bandwidth and operators? Today, let me recommend a must-bookmark professional tool website for all GISers — Submarine Cable Map.

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In recent years, applications such as digital museums, digital cultural heritage preservation, and digital scenic spots have become commonplace online. The 3D reconstruction technology behind them impresses with its stunning visual appeal—using just a screen, it can deliver an immersive experience. Nowadays, this kind of immersive virtual experience has permeated various industries. For example, in the popular game Black Myth: Wukong, the "Little Western Paradise" scene was created by capturing and reconstructing the Thousand-Buddha Cliffside Temple (Qianfo'an) in Xi County, Linfen, Shanxi Province. Similarly, Assassin's Creed: Unity used 3D technology to recreate the majestic Notre-Dame de Paris, achieving a remarkable synergy between the virtual and the real.

Above: The Thousand-Buddha Cliffside Temple in Xi County, Linfen, Shanxi Province.

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A few days ago, while processing some legacy DWG files left by the previous data team in QGIS, I was reminded of the company's AutoCAD replacement project from three years ago. That project, based on a open-source CAD software, was ultimately shelved due to the high costs of complex development. It got me thinking: it's already 2026, how have open-source CAD software options evolved? Are there any outstanding open-source alternatives? With these questions in mind, I searched some information. If you have other better recommendations, feel free to leave a comment for discussion.

FreeCAD

FreeCAD is currently one of the most popular open-source 3D CAD software, released under the LGPL license. It is suitable for fields like engineering, architectural design, mechanical design, and product design. Its core feature is parametric modeling, where all design elements are defined by parameters and formulas. When a parameter is changed, all dependent design elements update automatically. It comes with many features and tools for professional applications, including part design, assembly, motion simulation, material property management for mechanical engineering, and supports BIM (Building Information Modeling) workflows.

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On the evening of December 17, 2025, a strange incident occurred in Nanjing: citizens found that the Baidu, Gaode, and Tencent maps on their phones all "went on strike," and even Apple's built-in navigation was not spared. Some people were located "swimming" in Xuanwu Lake, while others riding shared bikes were prompted to be 57 kilometers away... The official announcement stated that this was due to temporary interference with satellite signals, though the military frequency bands of BeiDou were unaffected.

In a previous article Navigating Without GPS: Exploring Alternative Positioning Technologies - MalaGIS, we introduced several navigation and positioning methods besides GPS and BeiDou systems. However, those methods are either require professional equipment, need specific hardware support in phones, or are technologies that are not yet ready for large-scale commercial application. So, some friends have asked: how can I test if my GPS/BeiDou signal is being interfered with in such a situation, or how can I determine the credibility of my signal? Today, we recommend a method and tool for those who need it.

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If asked which software truly brought GIS (Geographic Information Systems) out of the ivory tower and made it a "must-have" on the average person's computer, the answer is likely one and only: Google Earth. Recently, the official Google Maps Platform released a special commemorative page celebrating the 20th anniversary of Google Earth's release. Hearing this news will surely take many veteran GIS professionals back to the moment they first spun the blue planet on their screens and first searched for their own rooftop. This editor first used Google Earth before university; perhaps by chance, or perhaps inspired by it, I ended up entering this field. Taking this opportunity, let's talk about the evolution of the world's most influential GIS software.

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It has been some time since the GPS and BeiDou signal anomaly incident in Nanjing. While the cause of the incident remains debated, an interesting question has been frequently discussed in the 'Malagis' GIS group recently: If one day, both our GPS and BeiDou signals are abnormal, and we don't have access to military-grade bands, how can we determine our location? The author has previously written a bit on this topic. Drawing from the group members' discussions and collected materials, here is a summary. Corrections are welcome if any inaccuracies are found.

Before delving into this topic, let's introduce a new concept: All-source Positioning. In this era of the Internet of Everything, the heavily relied-upon GPS is not omnipotent. Satellite signals cannot penetrate thick reinforced concrete or travel underwater. All-source positioning involves integrating various other sensors to provide alternative solutions when GPS fails. So, what are the current common solutions? Let's explore them.

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In the GIS field, especially when creating CIM digital twin scenarios, building white model data is often required. I have previously used many such building white model datasets (such as global building footprint data released by Google and Microsoft), but I frequently encountered situations where only the "footprint" was available without height information, or the height was randomly generated. A few days ago, I came across an interesting dataset online: GlobalBuildingAtlas, which can precisely solve the problem of missing height information. The data is global in scope, so interested friends should not miss it.

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The other day, while casually browsing in the MalGIS community chat, a friend @Tiantian suddenly asked me, "Does ArcGIS Pro 3.6 not support Windows 10 anymore?" This sudden question gave me a fright. After all, many friends following MalGIS should still be on Windows 10, some even on Windows 7. If there were such an issue, it should have surfaced earlier. However, when the friend later showed me the evidence, I couldn't be sure for a moment.

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