S. Hassan Alavi’s Post

🌟Geospatial Insights: DSM, DTM, CHM🌟 💡DSM (Digital Surface Model): Captures Earth's top surface, including buildings and vegetation. 💡DTM (Digital Terrain Model): Represents the bare Earth, excluding surface features like buildings. 💡CHM (Canopy Height Model): Derived by subtracting DTM from DSM, isolating vegetation/building heights. Image: researchgate.net #Geospatial #RemoteSensing #GIS #EarthObservation 🛰️🌍

🌟Geospatial Insights: DSM, DTM, CHM🌟 ✅DSM (Digital Surface Model): Captures Earth's top surface, including buildings and vegetation. ✅DTM (Digital Terrain Model): Represents the bare Earth, excluding surface features like buildings. ✅CHM (Canopy Height Model): Derived by subtracting DTM from DSM, isolating vegetation/building heights. Image: researchgate.net hashtag #Geospatial #RemoteSensing #GIS #EarthObservation 🛰️🌍

🗺️ A bit behind on #30DayMapChallenge, but still going strong! For Day 26, I'm showing how map projections can alter and distort how spatial data is interpreted. Map projections try to portray the surface of the earth or a portion of the earth on a flat piece of paper or computer screen. In a lay man’s term, map projections tries to transform the earth from its spherical shape (3D) to a planar shape (2D) so that maps can be made on flat layers (e.g. maps). The data shown here is the WWF Marine Ecoregions of the World dataset - https://lnkd.in/dThmSHxd Originally projected with the World Geodetic System 1984, you can see how the data can be warped and distorted when projected onto other coordinate reference systems. #gis #mapping

🕵♂️ Identifying the precise location of an object is both a fascinating and intricate task. Every piece of information matters, and even the smallest detail can serve as a clue in helping us reach our objectives—whether it's a road sign, a traffic signal, terrain features, road markings, signboards, power lines, and more. Maps play a crucial role in GEOINT (Geospatial Intelligence) analysis. The following website contains a great collection of information and instruments you can use to practice and do your own research: https://lnkd.in/dNPxH75B

The process of identifying an object's location relies on analyzing even the smallest details, with maps being a key resource in geospatial intelligence. In the link below you will find a solid resource to freely use

🌟DSM vs nDSM: 🌟 💡1-Digital Surface Model (DSM): A DSM represents the earth's surface and includes all objects on it (such as buildings, trees, and other structures) as well as the terrain itself. It includes both natural and human-made features. 💡2-Normalized Digital Surface Model (NDSM): NDSM is a derivative of a DSM where the heights of all objects (such as buildings and trees) are normalized with respect to the ground level. Essentially, it removes the terrain information and leaves only the heights of the objects above the ground level. 🔍In summary, while DSM includes the elevation of both the terrain and the objects on it, NDSM only includes the height of the objects above the ground level, removing the terrain information. image source: up42.com #GIS #Mapping #SpatialAnalysis #Geospatial #DataScience #RemoteSensing

🌟DSM vs nDSM: 🌟 💡1-Digital Surface Model (DSM): A DSM represents the earth's surface and includes all objects on it (such as buildings, trees, and other structures) as well as the terrain itself. It includes both natural and human-made features. 💡2-Normalized Digital Surface Model (NDSM): NDSM is a derivative of a DSM where the heights of all objects (such as buildings and trees) are normalized with respect to the ground level. Essentially, it removes the terrain information and leaves only the heights of the objects above the ground level. 🔍In summary, while DSM includes the elevation of both the terrain and the objects on it, NDSM only includes the height of the objects above the ground level, removing the terrain information. image source: up42.com #GIS #Mapping #SpatialAnalysis #Geospatial #DataScience #RemoteSensing

🔺 What does Level of Detail (LOD) mean in 3D city models, and why is it important? 🌍 This quick guide answers these questions, explains The Open Geospatial Consortium (OGC) CityGML standards, and helps you choose the right LOD for your needs. Check it out to learn more! 👏 Many thanks to Hürcan Atay & SEDAT BAKICI for their valuable contributions! Read more👇 https://lnkd.in/gxtQcQPP #geospatial #geomatics #3dcitymodelling #levelofdetail #3dCadastre

Making topography from HydroATLAS, SRTM and Natural Earth

"A global distributed altitude (terrain height) data from Nevada Geodetic Laboratory 🏡 " I discovered a dataset that records 22000+ points of altitude around the world that can be potentially useful for validating Global Digital Elevation Map (GDEM) from this hashtag #ScientificData Paper (https://lnkd.in/eXewQZTQ). A big effort has been made to access the website (https://lnkd.in/eJK4RyRU) and collect all the GPS stations' height. Therefore, to avoid repetitive effort, I made a single geopackage file that contains all the records, document the process and publish it as an open data in hashtag #Zenodo (https://lnkd.in/eUQQS_7B).