TopoToImage 4.0 - Create Geocart image databases from digital elevation models

[jlertola]

Hi everyone,

From 1995-2005, I developed TopoToImage, a companion program to Geocart that converts elevation databases into colored shaded relief images. It had a gradient designer and options for hillshading and cast shadows. Over time, Apple's system changes made it impossible to maintain, so I stopped development. Recently, with help from Claude Code, I've successfully recreated TopoToImage in Python as TopoToImage 4.0.

This is a free tool specifically designed to work with Geocart for creating terrain visualizations.

TopoToImage converts freely available elevation databases (GMTED2010, GEBCO, SRTM, GTOPO30, etc.) into colored shaded relief images that can be loaded into Geocart as image databases. This gives access to elevation data that can be reprojected to any map projection that Geocart supports.

Workflow:
1. Download free elevation data (GMTED2010, GEBCO, SRTM, etc.)
2. Open in TopoToImage and select an area and scale
3. Apply color gradients with hillshading
4. Export as a Geocart Image Database
5. Load into Geocart and reproject to your desired projection

Features:
• Geocart Image Database export
• GeoTIFF export - Also compatible with QGIS and other GIS software
• Interactive gradient editor - Drag-and-drop color stops, save custom gradients
• Hillshading - Configurable light direction and cast shadows
• Database cropping/resizing
• Free and open-source (MIT license)

There is a lot of elevation data available in geographic coordinates (latitude/longitude). By converting this data to Geocart Image Databases, you can reproject terrain visualizations to any projection using Geocart

• Download: https://github.com/jlert/TopoToImage/releases/latest (Click "Assets" under v4.0.0-beta.2 to reveal the DMG file)
• Platform: macOS (Apple Silicon)
• Includes: Sample data, User Guide PDF, Elevation Data Sources guide
• The downloadable app currently works only on Macs with Apple Silicon processors (M1, M2, M3, M4)

Intel Mac or Windows users: You can run from source:
• Requires Python 3.8+
• Instructions: https://github.com/jlert/TopoToImage#qu ... rom-source
• Windows users: I'd especially appreciate feedback if you try it!

Note about installation: Because I haven't joined Apple's Developer Program ($99/year), macOS Gatekeeper shows security warnings on first launch. The included "READ ME FIRST.txt" has simple workaround instructions (right-click → Open).

This is a beta release and I'd love to hear your thoughts. The downloadable app currently works only on Macs with Apple Silicon processors (M1, M2, M3, M4) If you have an Intel Mac, you could download the source code and run it locally. Maybe the source code can also be run on a Window system. I would love if someone who has a Windows computer could try that.

-Joe Lertola

[Atarimaster]

Hello,

thank you for your work and your announcement. I downloaded TopoToImage yesterday and already was able to create an image of a kind that I hadn’t managed to get right before (see my posting here).

So far, I can say that I like the application, but it takes REALLY long to create huge images (21600 × 10800) on my Mac mini 2024; and I’ve already one suggestion: If you’ve created a preview image, it should be able to save it; because you might think that it actually is good enough or you might want to keep it for reference.

I will continue testing and come back here in (hopefully) a few days.
Keep up the good work!
Tobias

[daan]

Joe,

It’s great to see you back in action with TopoToImage. Many thanks for posting this. I see it’s already receiving praise in another thread.

Cheers,
— daan

[quadibloc]

Although I don't have a Macintosh with Apple Silicon, I did inexpensively purchase an old Power Mac at a used computer store that was closing down due to renovations of the mall in which it was located.
However, after a web search gave me the link I needed for the Wayback Machine, I see that the earlier version of TopoToImage was a commercial program, unlike the current one which is available for free. Well, at least 2.0 was; I suppose I should have moved forwards in the results to check for 3.0.

EDIT: I see that the changes to the Macintosh operating system occurred during the development of what would have been TopoToImage 3.0, and the program was abandoned before it could be offered for sale.