Add a map overlay (image or KML)
Put a georeferenced picture (JPG or PNG with a world file, or a ZIP holding both) or a KML file under your survey and grading maps, use it to plan a survey route, change its opacity and remove it.
In the app Map › layers button › Map Layers › + › Add Image Overlay / Add KML
An overlay puts your own map under the live map on every survey and grade screen. Use it for a drainage plan, a LiDAR map, a scanned plan or old tile maps. It can be a map ZIP, a picture with its world file, or a KML file of lines and shapes.
The overlay draws on top of the background imagery and under everything live: your position, survey breadcrumbs, design lines, coverage and the design boundary.
What you can add
- A map ZIP with a picture and its world file inside, for example
North 40 - map.zipfrom the owner portal. Use Add Image Overlay. This has the fewest steps: one file, one tap. Don't unzip it. Needs app v1.5.4 or later. - A picture (.jpg or .png) and its world file (.jgw, .pgw, .tfw, .bpw or .wld). The world file is a tiny text file with the same name that tells the app where the picture sits on the ground. Use Add Image Overlay and pick both files together. The world file must be in latitude/longitude (WGS84), not UTM or state plane.
- A KML file (.kml) of lines, shapes and points. Use Add KML. A KMZ is not accepted: unzip it to get the .kml first.
The same + menu also has Add WMS (an online map server), Drain-IQ, My LiDAR Fields and Drainage plan. See Map layers.
Before you start
Time: about 2 minutes.
- The file is on the tablet, in the
Downloadfolder. To put it there: Move files to and from the tablet. - You copied it while the tablet had internet. On the control module Wi-Fi the tablet can't fetch a file from Drive or email.
- A screen with a map is open: Survey, or the grade screen of any workflow. To practise, open a workflow and tap Simulate.
Add a map ZIP or a picture
Tap the layers button
Look at the column of dark square buttons at the bottom right of the map. Tap the one with a blue icon of stacked sheets. A window called Map Layers opens.
- Layers button. Dark square, blue stacked-sheets icon, bottom right of the map. On screens without the green height button above it, it's the top one.
Tap +
The + is in the top-right corner of the Map Layers window. A short menu opens.
With no overlays yet, the window reads No overlay layers
and Tap + to add a KML, WMS, or image layer
.
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- + (Add Layer). Top-right corner of the window.
Tap Add Image Overlay
It's the third line of the menu. The Android file picker opens and fills the screen.
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- Add Image Overlay. For a map ZIP, or a picture with its world file.
Read the name at the top left of the picker
The picker opens on the last folder it used, or on Recent. If the name at the top left already says Downloads, go to step 7.
- Three lines and the folder name. Here it opened on Recent, not Downloads.
Tap the three lines at the top left
They sit left of the folder name. A menu called Open from slides in from the left.
- Three lines. Top-left corner. Tap them.
Tap Downloads
The line called Downloads, with a down-arrow icon (the order of the lines can differ between tablets). You should see Downloads at the top left and your files below.
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- Downloads. The tablet's Download folder.
A map ZIP: tap it once
The ZIP has a zip-fastener icon. One tap picks it, and the picker closes. Go to the last step.
Got a picture and a world file instead? Do the next three steps.
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- The map ZIP. Tap it once.
A picture and world file: press and hold the picture
Keep your finger on the picture for about a second (Press and hold). A blue tick appears on it, and the top of the picker reads 1 selected.
Names are cut short here. The picture shows a small preview of the map and is large (MB). The world file has a plain page icon and is tiny (B).
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- The picture (.jpg). Map preview, 3.25 MB. Press and hold this one.
- Its world file (.jgw). Plain icon, 81 B. You tap it next.
Tap the world file
One tap. It gets a blue tick too, and the top reads 2 selected.
Picking the picture alone usually fails with No world file found…
.
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- The world file. Tap it once. The picture is already ticked.
Tap Select
Select is in the top-right corner of the picker. The picker closes.
- Select. Top-right corner.
- 2 selected. Both files are ticked.
Check it lines up
The app places the picture and zooms the map to it. A message along the bottom starts Added image overlay:
, followed by the file name, the picture size in pixels and the latitude range it covers.
Look where a road or field edge crosses the edge of the picture. It should carry straight on into the satellite imagery.
- Edge of the picture. The road lines up with the imagery: the overlay is in the right place.
- Layers button. Tap it again to change or remove the overlay.
Add a KML
Tap the layers button
The dark square button with the blue stacked-sheets icon, bottom right of the map (step 1 above). The Map Layers window opens.
Tap +
Top-right corner of the window.
Tap Add KML
It's the first line of the menu. The file picker opens. If the name at the top left isn't Downloads, open Downloads as in steps 4 to 6 above.
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- Add KML. First line of the menu.
Tap the .kml file once
Only .kml files can be tapped. Every other file shows greyed out.
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- A .kml file. Dark text: tap it.
- Any other file. Greyed out: it can't be picked here.
Tap Close
The picker closes and you're back in Map Layers. It now has a row with a KML badge and the file name. Tap Close at the bottom right of the window.
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- The KML row. KML badge and file name. KML rows have no arrow and no opacity slider.
- Close. Back to the map.
KML layers always draw in the app's own style: blue lines, blue shapes with a light fill, and points as amber dots. Colours and names from the file are not shown. A file with nothing the app can draw gives No features found in KML file
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Change or remove an overlay
Start with the layers button on the map. Each overlay has its own row in Map Layers.
To hide it for a while: tap its switch
The switch is near the right end of the row. The overlay disappears from the map but stays in the list. Tap again to bring it back.
To see through a picture: tap the small arrow at the left end of its row
An Opacity slider opens under the row. Pictures start at 100 %.
Drag the Opacity slider to the left
It moves in 5 % steps. The imagery and your breadcrumbs show through the picture. KML rows have no slider.
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- Arrow. Opens the opacity slider (pictures only).
- Switch. Hides or shows the layer.
- Opacity. 5 % steps; pictures start at 100 %.
- Trash (Remove layer). Removes this layer.
- Clear All. Removes every overlay.
To remove one overlay: tap its trash icon
The trash can at the right end of the row.
To remove them all: tap Clear All
At the bottom of the window, left of Close.
Layers can't be renamed or put in a different order.
Use the overlay to plan a survey route
The app doesn't turn an overlay line into a survey or a design. Use it as a guide on the screen:
Add the overlay first
Before you start the survey, so you can see the route you planned.
Drive the survey along the line
Start at the outlet or the high end and follow the planned route on the picture. See Survey a route.
Design from your survey
The app designs the grade from your RTK survey, not from the picture or the LiDAR behind it.
If the picture hides your breadcrumb trail, lower its opacity.
If it doesn't work
The overlay is gone
Overlays are not kept after the app closes, and Clear All or the trash icon removes them at once. Add it again: the file is still in Download.
No world file found. Select the image (.jpg) and world file (.jgw) together, or a .zip containing both.
Select the picture and the world file together, or pick a ZIP holding both. A .jpw world file is not read: rename it to .jgw.
No image file found. Select the image (.jpg/.png) and world file (.jgw) together, or a .zip containing both.
No picture in what you picked. Check it is the right ZIP. On an app older than v1.5.4, ZIPs are not read: update, or unzip and pick the two files.
World file uses projected coordinates (UTM/meters). Only WGS84 (EPSG:4326) geographic coordinates are supported. Re-export the world file in lat/lon.
Export the picture again from its program in latitude/longitude (WGS84).
The picture is in the wrong place
The world file belongs to a different export, or the picture was resized or edited after export. Export them again together.
A KMZ or KML can't be picked
Add KML only lets you pick .kml files; a .kmz shows greyed out. Unzip the KMZ to get the .kml. A KML that doesn't show at all is usually in a different folder: check the name at the top left of the picker (Open the file in the app).
All KML lines look the same blue, without names
Expected: the app does not use KML colours or names. Use a picture overlay when you need labels.
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