Use the layer menu in the upper-right to control map overlays and base maps; see the current layer order below. Tap TOOLS at the upper-left to open the tool drawer; tap TOOLS again to close it. ADD POINT and DRAW LINE stay beside TOOLS for quick access. The zoom buttons are at the lower-right.
Tools drawer and controls
TOOLS drawer
Tap ☰ TOOLS to open the drawer, and tap the same button again to close it. The drawer stays open when you use its controls or interact with the map.
The drawer groups controls under GPS & TRACKING, GPX TRACKS, POINTS & MEASURE, and DISPLAY. MAP GUIDE and LEGEND are also accessible there.
Use the upper-right layer checkboxes to show or hide individual overlays, including GPS tracks and imported GPX files.
Button colors and map controls
TopoTac uses a black, white, and orange interface. The GPS ON button turns bright red with white text while GPS tracking is active. ADD POINT also turns bright red while point-placement mode is active. DRAW LINE turns bright red while line drawing is active.
Tap a map location to read its coordinates at the lower-left; the situs address display sits just above it. Use the + and − zoom controls at the lower-right.
Layer menu reference — current order
The upper-right layer menu lists three base maps first (Street Map, Topo Map, Aerial Imagery). Below them, overlay checkboxes appear in this order:
- GPS Track Lines — Your own GPS recorded tracks.
- Marked Points — Points you place on the map.
- Drawn Lines — Show or hide saved lines without deleting them.
- OR LiDAR — Oregon terrain hillshade.
- OR TRS — Township, range, and section boundaries.
- Josephine Co Taxlots — Josephine County parcel boundaries.
- Jackson Co Taxlots — Jackson County parcel boundaries (orange styling).
- OR State Taxlots — Statewide parcels, including both counties, available as backup.
- OR Public Land — Mapped public land ownership.
- Lakes/Ponds ¼ Acre+ — Mapped lakes and ponds.
- OR New Fires (24Hr) — Recently reported Oregon fires.
- US Current Fires — Current mapped fire perimeters.
- OR Historical Fires — Past Oregon fire perimeters.
- OR RAWS WX — Oregon remote weather stations.
Choose one base map at a time; check or uncheck overlays independently. Imported GPX files add their own named entries when opened, so those entries may appear in addition to this default list. Long filenames may be shortened visually in the menu.
Base maps and terrain
Street Map
Roads and place references.
Topo Map
Terrain and topographic context.
Aerial Imagery
Satellite and aerial-style imagery.
DOGAMI LiDAR
Terrain hillshade overlay.
Land-survey and natural features
OR TRS
Public Land Survey System overlay.
OR Public Land
Oregon Department of Forestry ownership overlay.
Lakes/Ponds ¼ Acre+
USGS mapped waterbodies.
Tax lots and parcel addresses
County parcel layers
Josephine Co Taxlots and Jackson Co Taxlots use their respective county assessor parcel services. OR State Taxlots covers all of Oregon, including both counties, and can be switched on as a backup. If both a county layer and the statewide layer are enabled, their parcel lines may overlap. Jackson county outlines are testing server-side orange styling with automatic fallback to default styling.
Parcel outlines load only for the visible map area at zoom 14 or higher. Enable the corresponding layer to click a parcel for owner, situs address, mailing address, taxlot identifier, acreage and other attributes when reported by that source. No additional county source is queried to complete the popup.
GPS Situs Address
The floating Situs box identifies the parcel at the current GPS position, whether or not any parcel boundary layer is enabled. When GPS is switched off it shows Situs: GPS off; the last address is not retained.
GPS situs checks are limited for small movements and short time intervals. Parcel addresses are reference information only, not a legal survey or proof of ownership or access.
Fire and weather overlays
OR New Fires (24Hr)
Recent incident locations across Oregon from the NIFC/IRWIN feed.
Click a marker for the incident name, type, discovery date/time, county, and protecting agency when reported. The layer refreshes periodically; feed information may be incomplete or delayed.
US Current Fires
Shows current NIFC fire perimeters intersecting the visible map area at zoom 9 or higher, wherever the source provides coverage. Click a perimeter for its reported name, county, and mapped acreage when available.
The outline and fill indicate the mapped perimeter, not necessarily the exact location of active flames or the current evacuation boundary.
OR Historical Fires
Displays Oregon-filtered historical fire perimeters from 2020 onward, intersecting the visible map area at zoom 9 or higher, subject to records returned by the service.
Click a polygon to view available incident information, discovery and perimeter dates, acreage, containment information, and coordinates.
OR RAWS WX
Active RAWS weather stations throughout Oregon (the current query is statewide).
GPS, recording, and GPX tools
GPS & TRACKING
SCREEN MUST STAY ON TO RECORD
GPS ON: Requests browser location permission, shows your position and records the route as GPS fixes arrive. The button turns bright red while active; turn GPS off to stop updates. The map centers on the first reported position.
CLEAR GPS: Clears recorded GPS track segments without switching GPS positioning off.
SAVE GPX: Downloads the recorded GPS track as a GPX file. It does not stop recording or clear the current track. Save a copy before clearing browser data.
GPS STATS: Expands or collapses the live GPS readout described below.
Use the GPS Track Lines checkbox in the layer menu to hide or show the line without stopping GPS recording. Interrupted tracking may appear as separate segments.
GPS STATS — field readout
Tap GPS STATS to view the current position and track statistics. The top heading reads CURRENT POSITION (When GPS is on).
- DD: Decimal degrees, such as 42.436800, -123.140000.
- DDM: Degrees and decimal minutes, such as 42° 26.2080' N / 123° 08.4000' W.
- DMS: Degrees, minutes, and seconds.
- GPS fix: Reported accuracy in meters, speed in mph, and heading in degrees when the browser provides them.
- Recorded track: Total distance in miles and kilometers, number of points, and session elapsed time.
Missing GPS values display as unavailable. Track distance is calculated from recorded positions and can vary with GPS accuracy. This panel shows current coordinates only when a position fix is available.
OPEN GPX / CLEAR GPX
Tap OPEN GPX to import one or more GPX files stored on your device. Each imported file receives a separate checkbox in the layer menu.
- Routes and tracks are displayed as line segments; named waypoints and start/end markers may appear.
- The map zooms to the imported track extent.
- Tap CLEAR GPX to remove imported GPX layers. This does not erase the GPX files on your device.
- Imported GPX files are read locally by the browser; the import function does not upload them to the map server.
Track storage and export
TopoTac may retain track segments in browser storage when available, but browser data is not a permanent backup. Use SAVE GPX to keep a separate file on your device.
Saving a GPX export does not clear the recorded line. The GPS Track Lines layer checkbox controls visibility; CLEAR GPS controls deletion of the recorded track.
How map data is loaded
Visible-area requests: Base maps request tiles around the current view. OR LiDAR, OR Public Land, OR TRS, and the three taxlot layers request images for the visible extent. Tax lots display at zoom 14 or higher. US Current Fires and Lakes/Ponds ¼ Acre+ query the visible area at zoom 9 or higher; their source services are not restricted to Oregon.
Oregon-filtered requests: OR Historical Fires queries Oregon incident records from 2020 onward, within the visible map extent at zoom 9 or higher. OR New Fires (24Hr) and OR RAWS WX retrieve statewide Oregon point data regardless of zoom.
On-demand requests: Parcel details are queried on map clicks at zoom 14+ when the relevant parcel layer is enabled; GPS situs addresses are queried independently of layer visibility for the reported GPS position. GPX files are read locally.
Remote layers generally load when enabled. The current perimeter layer refreshes periodically; historical perimeter requests are view-driven. Data availability, geographic coverage, and provider limits may affect completeness.
Draw Lines
DRAW LINE: Tap the button immediately to the right of ADD POINT. Tap the map to place each vertex in order; the line connects the taps. This is tap-to-place drawing, not freehand.
The temporary toolbar shows UNDO (remove the last vertex), FINISH (finish a line with at least two vertices), and CANCEL (discard the unfinished line). A tip reminds you: Tap a finished line to export GPX or delete it.
After FINISH, enter a line name and choose Orange, Red, Blue, or Black from the color dropdown, then tap SAVE LINE. The completed line is saved automatically in this browser and restored when you reopen TopoTac. Repeat to draw more lines.
The Drawn Lines checkbox in the upper-right Layers menu shows or hides completed lines without deleting them. It is checked by default.
Tap any finished line to see its name and length, EXPORT GPX to download that line as a separate GPX file, or DELETE LINE to remove it. Exporting does not delete the saved line.
Marked Points
ADD POINT: Tap the button beside TOOLS to enter placement mode. It turns bright red with white text while active. Tap the map to create numbered orange markers; tap ADD POINT again to exit. In normal mode, tapping the map updates the coordinate readout and can inspect parcel information.
Marker balloon: Tap a point to see its coordinates in DDM and decimal degrees, copy its coordinates in degrees and decimal minutes with N/S and E/W (for example, 42° 26.208' N, 123° 08.400' W), rename it, or delete just that point. Drag a marker to reposition it.
ENTER COORDS: Type latitude and longitude in degrees and decimal minutes (the default) or decimal degrees, optionally name the point, and select PLACE POINT. West and south coordinates are negative unless using W/S direction letters.
CLEAR POINTS: Deletes all marked points after confirmation. The Marked Points checkbox in the layer menu only hides or shows them.
Points are stored in this browser and restored when the map reopens, as long as browser storage remains available. Clearing browser data may erase them. Points are independent of GPS and imported GPX tracks.
Points and acreage measurement
MEASURE AREA / CLR MEASURE
Open TOOLS and select MEASURE AREA. Tap the map to place the corners of an area. Once you have at least three corners, tap FINISH MEASURE to complete the polygon.
TopoTac displays the approximate area in acres, draws an orange outline and translucent fill, and places an acreage label on the map. Tap CLR MEASURE to remove the measurement without deleting marked points.
Starting a measurement exits ADD POINT mode so map taps are interpreted as polygon corners rather than new marked points.
Coordinate display
Click Map for Coordinates: click a point on the map to display its latitude and longitude in degrees and decimal minutes.
Example format: 42° 26.208' -123° 08.400'
Negative longitude values indicate west. The coordinate display is intended as a convenient location reference; confirm coordinates and boundaries against authoritative data when precision matters.