GeoPDFs
GeoPDF overlays are currently available on Android only. iOS support is planned for a future release.
Mapit GIS Professional can import GeoPDF files - PDF documents that contain embedded geospatial metadata - and display them as map overlays. GeoPDFs are commonly produced by government mapping agencies, land management organizations, and GIS software.
What is a GeoPDF?
A GeoPDF is a standard PDF file with additional geospatial information embedded in its internal structure. This metadata defines how the map content on the page relates to real-world coordinates, allowing GIS applications to correctly position the PDF on a map.
Not all PDFs are GeoPDFs. A regular PDF of a map image has no embedded coordinates and cannot be used as a georeferenced overlay. Only PDFs specifically created with geospatial metadata will work.
Supported GeoPDF standards
Mapit GIS supports two GeoPDF standards:
ISO 32000 (recommended)
The modern open standard used by most current GIS software. Geospatial data is stored in Viewport (VP) entries with Measure dictionaries containing geographic corner points (GPTS).
Used by: USGS, many government agencies, QGIS, ArcGIS
TerraGo
An older proprietary format developed by TerraGo Technologies. Uses LGIDict dictionaries with projection parameters, coordinate transformation matrices, and neatline polygons.
Used by: Older government datasets, TerraGo software
Importing a GeoPDF
- Open Offline Maps from the main menu
- Switch to the GeoPDFs tab
- Tap the + button
- Browse to and select your
.pdffile - The PDF will be processed - geospatial metadata is extracted and the map page is rendered as an image overlay
The first page of the PDF is rendered as the map overlay. Multi-page PDFs are supported but only page 1 is used.
Managing GeoPDFs
Once imported, GeoPDFs appear in the GeoPDFs tab of the Offline Maps screen. You can:
- Toggle visibility - show or hide the overlay
- Adjust transparency - blend the PDF map with the base map (0-100%)
- Reorder layers - drag and drop to change stacking order
- Zoom to extent - jump to the area covered by the PDF
- Delete - remove the PDF from the list and delete the files
Example data sources
USGS Topographic Maps (US Topo)
The USGS provides free GeoPDF topographic maps covering the entire United States. These are high-quality 1:24,000 scale maps with terrain, roads, buildings, and other features.
To download:
- Visit the USGS topoView website
- Navigate to your area of interest
- Click on a map quad and download the GeoPDF version
- Import the downloaded
.pdffile into Mapit GIS
Natural Resources Canada (NRCan) Topographic Maps
Canada provides GeoPDF topographic maps through the GeoGratis portal. Available at various scales including 1:50,000 and 1:250,000.
State and local government maps
Many US state agencies, forest services, and land management offices distribute GeoPDF maps for parks, trails, and public lands. Check your local agency's GIS data portal.
Creating GeoPDFs
From QGIS
- Set up your map project in QGIS with the layers and styling you want
- Go to Project > Import/Export > Export Map to PDF
- In the export dialog, check Create Geospatial PDF (GeoPDF)
- Select the GeoPDF format (ISO 32000 recommended)
- Click Save to export
From ArcGIS
- Open your map in ArcGIS Pro
- Go to Share > Export Map
- Select PDF as the format
- In the PDF options, enable Export Map Georeference Information
- Export the map
Limitations
- 200 MB file size limit - larger PDFs are rejected at import
- Page 1 only - only the first page of multi-page PDFs is rendered
- Render resolution - PDFs are rasterized at up to 2048 pixels on the longest side. Very large-format PDFs may lose fine detail
- No layer control - all PDF layers are rendered as a single composite image
- WGS84 coordinates required - the PDF must contain geographic coordinates (latitude/longitude). PDFs with only projected coordinates are not currently supported