Geospatial Data

Georeferencing is assigning real world locations to a raster.

Here, we are referring to georeferencing scanned maps and assigning coordinates to different parts of the image. This allows you to overlay the map with other maps and data in a system that understands coordinates, such as a GIS or a web map.

Different raster formats can be used as inputs for different tools. Common choices are TIFFs and JPGs. If your image is a PDF, you may want to convert it first in Photoshop or another program from PDF to a TIFF or JPG.

Things to consider when choosing a method for georefrencing:

• What output format do I want? GeoTIFF? WMS? Tiles?
• Is this a map I want to share online or keep offline in a desktop environment?

QGIS - open source, desktop GIS

ArcGIS Pro

AllMaps - for lightweight georeferencing of maps that are hosted already in a IIIF environment, such as many scanned maps available via https://geo.btaa.org