Custom Layers

This article gives descriptions of the types of custom layers available in CalTopo.

MapBuilder Layer

So you like the functions of the MapBuilder layer, but need to adjust it to fit your needs? Create your own and add it to your account! (Pro subscription or higher required.)


Choose your features from the options and hit save to view your layer. Once you have it set the way you want, Save to Your Account to be able to access it on all of your maps.

Mapbox Tileset

If you have images or shapefiles that you want to convert to a custom layer, you can do so using the program MapBox, and then access those via this feature. For example, you could build a base layer from drone images. More information.

Viewshed Analysis

This layer will draw a color over areas of the map that you can theoretically see from a given point, at a given height above that point. This may differ in real life due to tree cover or other obstructions.

When you begin a viewshed analysis, a red circle with a dot in the middle will appear in the middle of the map viewer, along with a small dialog box in the lower right corner. You can click and drag the circle to any point on the map. This point should be the place you want to see the viewshed analysis from.

Once you have the location set, name your layer in the dialog box, and select how far off the ground you want the analysis to calculate (the defualt is 20m, but you may want something like 2m to simulate a human standing there). You can also change the color for the layer when it is displayed.

After you hit OK, the layer will populate (it may take a moment to process), and the areas that are visible from your designated point will be shaded with the color that you chose.

Custom Relief

Though we offer three types of relief shading in the layers menu, this is another option for creating your own relief for your purposes.
Pick an azimuth (compass direction) and zenith (angle above the horizon) and click “Add Lighting”. Mix and match multiple combinations to reach your desired effect. More information here and here.

DEM Shading

With this feature, you can create custom shading schemes based on elevation, slope, aspect, and tree cover. To create the layer, develop a rule using the options on the right hand side of the dialog box. Select the type of rule with the checkboxes, then the specifics with the menus or numeric values where appropriate. Hit Add Rule to move the rule into the rules box. When you have assembled your rules for your new layer, hit OK or save to account.
The Load From feature allows you to use a previously created layer to begin your rule set. An example use for this would be to find areas between 0-2% slope angle and and an east-facing aspect to find flat campsites that might get morning sun.
More information.

Sunlight Analysis

Speaking of finding a campsite with morning sun, with this tool you can see just that. Specify a date, and either pick a specific time or get an average across the entire day, and you'll get a display of the sunlight at that time of day or year or overall.
This feature take a few minutes to load and slows down your map if you leave it on. You can also view it from overlay menu for quicker toggling between times of day.

Archived MODIS

Find daily satellite images going back to 2012. These are a low resolution, but still have their purposes for regional-level uses. More information.

Map Sheet

New in 2020, we've replaced Geospatial Images with Map Sheets. Map sheets are any image that can be referenced to a point on the surface of the earth to be placed on a map. They can be a JPG, TIFF, or PDF file.
We’ve started this layer with a huge variety of public mapping data from BLM, USFS, State, and Local resources and we will continue to add to this layer. The Shared Map Sheets feature is available for all users,
Any user can submit a map to be reviewed for this layer at CalTopo will review the map for quality as well as assess any copyright issues. If you are a copyright holder of a number of maps (such as a representative of a trails organization, local government, or parks organization) please e-mail us at to discuss copyright. CalTopo will provide on map hosting of your content and help provide it to other CalTopo users.
For pro, desktop, and team users we’ve also added the ability to upload a map sheet for personal use, including hosting of files by CalTopo! If the data source contains geospatial alignment data (such as a georeferenced PDF file) the file will automatically be placed in the correct spot, otherwise manual alignment is still required. This supplements and replaces the former “Geospatial Image” layer. This has been moved to a paid feature since CalTopo is now hosting an image. If you previously had Geospatial images in your account you’ll still access to those images
Additionally features have been added to allow display and layering of these map sheets. In the layers toolbar a zoom to extent (which zooms to fit the map sheet), a crop to neatline (trim any writing/excess white space on map sheet), and opacity sliders are now included for each map sheet.
More information.

Custom Source

Custom source provides the opportunity for you to add other sources of map data. CalTopo supports bringing in custom maps with 3 different types of delivery: WMS, WMTS, and Tile Server. If have access to tiles that are hosted elsewhere, you can use this tool to bring them in to the CalTopo interface.