GIS File Format FAQ

When working with geospatial data, understanding file formats is essential to managing, sharing, and visualizing information effectively. From raster imagery and vector features to 3D models and point clouds, each file type can play a vital role in GIS workflows. 

In this article, we’ll answer some of the most common questions about file formats and how they’re handled in Global Mapper®.

Foundations of File Formats:

What is the difference between raster and vector formats?

A raster file is a grid of pixels, each representing information such as color, temperature or elevation. Examples include satellite imagery, heat maps, or terrain grids. 

A vector file is made up of points, lines, and polygons that define features such as roads, property boundaries, or buildings. 

Can I open any file in any GIS software?

Global Mapper supports over 350 different file formats for import, including popular formats like  Shapefile, CAD, and Geodatabase. 

However, some proprietary formats cannot be opened directly in GIS software — for example, raw lidar data from a DJI drone. In these cases, you’ll need to use the manufacturer’s software to convert the data to a standard format, such as LAS.

Do all file formats store CRS information?

Not all file formats store coordinate reference system (CRS) information. Formats like GeoTIFF, GeoJSON, and JPEG2000 (JP2) can store this geospatial information in their file headers, while others, such as ASCII raster, cannot. 

When CRS data isn’t stored in the file, it may be saved in a separate “sidecar” file (like a .prj file). Global Mapper also allows users to manually assign a CRS or use rectification (georeferencing) tools. For 3D formats such as OBJ, STL, or PLY, users typically need to define or supply the coordinate system to correctly position the model on a map

Can I store multiple layers in one file?

The ability to store multiple layers in one file depends on the format. Some formats, like Shapefile, only store a single layer, while others, like GeoPackage or File Geodatabase, can save multiple layers in one file. 

In Global Mapper, users can export data to a Global Mapper Package (.gmp) file, which stores all loaded data — raster, vector, and point cloud layers — along with workspace settings. This provides a convenient and flexible way to share complete projects between Global Mapper users.

What File Format Should I Use?

What is the best format for storing elevation data? 

GeoTIFF is often recommended for storing elevation data. It combines the flexibility of a raster grid with embedded geographic information, making it accurate, efficient, and easy to share. If elevation data is in the form of a point cloud, LAS and LAZ are recommended.

What is the best format for storing satellite data?

Similar to elevation data, GeoTIFF and Cloud Optimized GeoTIFF (COG) are ideal for storing satellite imagery. These gridded formats store pixel values along with embedded geographic information, ensuring both spatial accuracy and broad compatibility.

What are LAS and LAZ files, and how do they differ from raster or vector data?

LAS and LAZ are standard formats for storing point cloud data, developed by the American Society for Photogrammetry and Remote Sensing (ASPRS).

• LAS is an uncompressed binary format ideal for direct processing but results in larger file sizes.
• LAZ is a losslessly compressed version of LAS, typically about 90% smaller while retaining all data.

Point clouds, which are collections of 3D points (XYZ coordinates), are technically a type of vector data, though they differ from traditional GIS features. They are often used to generate raster outputs such as DEMs, 3D meshes, or terrain models. Each point can include attributes like classification, intensity, color (RGB), or return number.

Is a PDF a Vector file?

A PDF can be either vector or raster, usually depending on how it was created. PDFs generated from software like Adobe Illustrator are vector files, while those from programs like Photoshop are rasterized.

A quick way to tell the difference is to zoom in on the PDF. If lines and text remain crisp, it’s vector; if they become pixelated, it’s raster. Global Mapper can import and export both raster and vector PDFs.

What is a Shapefile & why does it have multiple components?

A Shapefile is a vector data format created by Esri that stores geospatial features and their attributes. This format is made up of multiple files, zipped together for sharing and storing:

• .shp – Stores the geometry (points, lines or polygons)
• .dbf – Stores attributes in a DBase format
• .shx – An index linking geometry and attributes
• .prj – Defines the projection and coordinate system

What is the difference between a Shapefile and GeoPackage?

Both Shapefiles and GeoPackages are vector data formats, but they differ in flexibility and capacity:

• A Shapefile consists of multiple files and can store only one layer of data. It also has size and field name limitations.
• A GeoPackage (.gpkg) is a single SQLite-based file that can store multiple layers, larger datasets, and a wider range of geometry and attribute types.

GeoPackage is generally the preferred modern alternative for multi-layer vector storage.

How to convert between formats like KML, Shapefile, and GeoJSON?

Global Mapper makes it simple to convert between file formats, such as Google Earth KML, Shapefile, and GeoJSON. Load the file into Global Mapper, then export it to your desired format. To convert multiple files at once, navigate to the File menu > Batch Convert/Reproject.

How can you convert KML to KMZ?

To convert a KML file to KMZ in Global Mapper, open the KML, click export (as a KMZ) and check the “Create Compressed KMZ File” option in the export dialog box. 

What is the difference between TIFF and IMG files?

Both TIFF and IMG are raster formats. IMG is a proprietary format developed by ERDAS, known for handling large datasets efficiently. Global Mapper supports the IMG format; however, due to its proprietary nature, it has limited compatibility outside ERDAS environments. TIFF (and GeoTIFF) is an open, widely supported format that embeds spatial reference information. Although TIFF files can be large and aren’t directly viewable in most browsers, they’re highly interoperable across GIS platforms. 

CAD and 3D Formats

What is the difference between GIS and CAD files?

CAD formats are often used by architects, engineers, and surveyors to create high-precision drawings and measurements.  These 2D or 3D models often serve as a digital blueprint for design and engineering. from building plans to mechanical parts. Common formats include DWG and DXF.

GIS files are designed to model the real world, storing various geospatial information for mapping, visualization, and spatial analysis.

Converting between CAD and GIS formats is common. For example, Global Mapper makes it easy to convert a DWG file to a Shapefile (SHP) — or vice versa.

What are common CAD formats, and the difference between them? 

The following CAD (Computer-aided design) formats are all supported by Global Mapper, but come from different software ecosystems:

• DWG – Native to Autodesk AutoCAD, typically contains a single design model per file. Compact and supports a wide range of drawing types.
• DXF – An open, text-based (ASCII or binary) format developed for data exchange between CAD applications. It’s larger and less compact than DWG but highly portable.
• DGN – Developed by Bentley Systems for MicroStation (short for DesiGN). It can store both 2D and 3D design data, making it suitable for complex engineering and infrastructure projects.

What is the difference between 2D and 3D GIS formats?

In simple terms, 2D data consists of (x, y) coordinates, while 3D data includes a (z) value representing height or elevation.

Diving deeper, 3D models describe the complete geometry and can include internal or structural details — for example, the inside of a pipe. While raster elevation data (like a terrain grid DEM) can be viewed in 3D, it’s technically a 2D data structure because it cannot represent complex geometry such as overhangs, caves, or the space beneath a tree canopy.

What is the difference between 3D OBJ, STL, GLB, and PLY?

OBJ, STL, GLB and PLY are all common 3D model formats:

• OBJ (Object File Format) – A polygon-based mesh format commonly used in computer graphics. It’s text-based, making it easy to read and edit, while also being widely compatible. It stores attributes like texture and shading but not animation, resulting in large file sizes.
• STL (Standard Tessellation Language) – Represents surfaces as connected triangles and is widely used for 3D printing. This format doesn’t store metadata such as color and texture, and therefore has a smaller sized file but can be difficult to edit.
• GLB (GL Transmission Format Binary) – A modern 3D format developed by the Khronos Group, is designed for efficient transmission and rendering on the web. GLB files store geometry, materials, textures, and animations in a single compact binary file, making them ideal for web-based 3D visualization and AR/VR applications.
• PLY (Polygon File Format) – Creates a surface from a network of triangles. It supports ASCII and binary representations and can store attributes like color and texture. It is supported by many 3D modeling and scanning software, however is not as universally compatible as OBJ or STL.

How to convert between 3D and GIS formats?

Global Mapper not only supports popular 3D file formats such as OBJ, STL, and PLY, but allows users to convert between data formats.

To convert a 3D model into GIS features, navigate to Layer > Create 3D Areas from 3D Models. This process generates 3D vector features from the model’s geometry; however texture information will not be retained.

A 3D mesh can also be created from lidar by navigating to the Create 2D Model from Selected Lidar Points tool in the Lidar toolbar, or right-click to Advanced Feature Creation Options > Create 3D Model from Selected Lidar Points

Try Global Mapper 

No matter your industry or application, mastering file formats is an important step toward getting the most out of your geospatial data and tools. Global Mapper streamlines these tasks by supporting hundreds of file types, making it easy to import, convert, visualize, and export your data—whether you’re working with lidar point clouds, CAD drawings, or high-resolution imagery.

References

3D Model Credits: “Paris” (https://skfb.ly/oHU8O) by TerraMesh is licensed under Creative Commons Attribution (http://creativecommons.org/licenses/by/4.0/).