Trace your fields, or use your GPS to instantly calculate field area

ExpertGPS calculates field acreage down to the square foot. Instantly. Without any calculations or complicated math on your part. Just click and draw. Or upload waypoints or track logs from your GPS. All you have to do is download the 30-day trial of ExpertGPS and follow these simple step-by-step instructions below.

SH asks:
I have 174 waypoints coordinates and I would like to calculate the area of the farmland based on those coordinates. How do I do that using GPS Expert?

Calculating Area of a Farm Field Marked with GPS Waypoints

Click Receive from GPS on the GPS menu in ExpertGPS. All of your GPS waypoints will be shown on the map. Use the Route Tool to connect the waypoints marking the corners of your field.

Show the Area of your Field

On the View menu in ExpertGPS, click Show Route List. Then click Select List Columns. Add the Area column. ExpertGPS displays the area of all of your fields.

Converting between Acres, Square Feet, and Hectares

To convert the area calculated by ExpertGPS between acres, square feet, hectares, or another unit, click Preferences on the Edit menu, and click on the Units tab.

Download ExpertGPS, and Calculate the Area of your Fields Now!

Download the free ExpertGPS demo and follow these simple step-by-step instructions to calculate the acreage of your land and fields.

Dale writes:
My application requires that I measure the areas of various land use types within a given project area. I had problems when I tried to append a particular shape of one land use to another shape of a different land use. I had to leave a gap to keep things from getting messy. I think I have that issue resolved by assigning each land use type to a different layer. I also had problems when I placed a node off location. I could not find a way to 'grab' the node and move it to the correct location (feature request). Deleting the shape and re-drawing it is a pain.

There are a couple techniques you can use if you are drawing filled objects that need to mesh right up against each other. If they have straight sides (not curved like a river centerline), it might be easiest to draw them using the route tool, and then convert the routes to shapes after. This is because the route tool automatically snaps to waypoints as you draw. So if you are drawing agricultural fields, and put waypoints at all of the field boundaries, as you use the route tool to "connect the dots" you'll get routes that align perfectly with the adjacent fields.

As you begin to draw a new route, ExpertGPS might show a + cursor, meaning that is going to extend an existing route. If this isn't what you want, hold SHIFT to override this.

You can move nodes to a new position by selecting the waypoint at that node and using the Move Selected tool to move it to a new position.

Once you've got everything in place, select the routes and click Convert to Shape on the Tools menu. You can then delete the routes and waypoints.

If you need to make changes to shapes, it's possible to do so. Click once with the select tool to select the shape, and then drag a selection rectangle over the node you want to move. It should be highlighted in magenta. Now switch to the Move Selected tool and drag to the new location.

Bill G. asks:
I see that I can enter my hunting areas with expert GPS and did see some farm capabilities. How easy is it to put fence lines and gates on the maps? Can I pull in a Google Earth image and draw directly on that? Can I add and remove layers? example, maybe I don't want to see the deer trails, can I hide them and then view them again later? Thanks for your help!

It's as easy as pointing and clicking. You can trace fence lines directly off the aerial imagery of your fields. ExpertGPS does have a Layers feature, but even easier is to simply hide the data you want to temporarily remove from the map. Select the data, right-click, and Hide. When you want to see it all again, click Show All on the Edit menu.

The View in Google Earth command in ExpertGPS allows you to view your GPS data (waypoints, routes, and tracks) over the detailed color imagery in Google Earth. To use the command, open a GPX file in ExpertGPS, or retrieve the data from your GPS. Press F7, or click View in Google Earth on the View menu. ExpertGPS will instruct Google Earth to synchronize its map to match the map in ExpertGPS, and to show your GPS data.

If Google Earth is not already running when you click View in Google Earth, it may not show your data because it is busy initializing. To prevent this, run Google Earth and let it finish initializing and zoom in on the globe. Then click View in Google Earth in ExpertGPS.

You can also export your data from ExpertGPS to a KML file, which you can then view in Google Earth. Click on the map in ExpertGPS, and then click Export Data on Map on the File menu. Change the file type to .kml, and save to your desktop. Open the KML file in Google Earth.

ExpertGPS cannot display Google Earth's worldwide color imagery directly. Google's terms of use forbid this. You can, however, export an image from Google Earth and use it as a Scanned Map in ExpertGPS.

The ExpertGPS help file has complete details about preparing and geo-referencing your maps for use within the program.

Related Topics Adding a Google Earth image to ExpertGPS

Drew S., a rancher in West Texas, asks:
I am a rancher in West Texas. I need mapping software that can print out maps for planning use on the ranch. This is what I need it to do:
1) import GPS routes to create roads and boundary fences and fields (using Garmin GPS 76), and waypoints.
2) The ability to edit the roads or to freehand a road or line on to a Nat. Geo. Topo or to aerial photos or to USGS soil survey maps.
3) Save different maps for each year (where deer blinds where in past years).
4) Use editing tools to mark, name and use symbols to identity areas on the map.
5) Be able to print out a map using my home printer.
Can your software do all this?

Yes, ExpertGPS will be able to do everything you're looking for in a ranch mapping software product. ExpertGPS will retrieve the Garmin waypoints and tracklogs you record around your ranch, marking roads, fences, and fields. ExpertGPS has a bunch of built-in styles so you can give all of the gravel roads on your property a different look than the paved ones, and you can color-code your fields based on crop type or any other attribute.

You can create roads by driving them with the GPS in the truck, or you can draw them in freehand with the Track tool in ExpertGPS, using the aerial photos for reference.

In addition to the built-in aerial photos and USGS topo maps in ExpertGPS, you can add your own scanned maps - I've written detailed instructions on calibrating a scanned map which will allow you to view your USGS soil maps or any other map of your ranch in ExpertGPS.

ExpertGPS stores your data in GPX format, which is the standard format for exchanging GPS data. If you want to compare deer blind, deer feeder, and scouting locations from different years, just save each year's data in a different GPX file. You can view any GPX file over any map in ExpertGPS, so it's easy to compare changes in deer behavior and sightings and place your blinds accordingly.

I've written a paper on using ExpertGPS, your Garmin GPS receiver, and your digital camera to build a photographic map of deer sign or any other data you'd like to collect on your ranch.

ExpertGPS makes it easy to add GPS data, photos, and your own notes to any map - there are tools for drawing directly on the maps and adding symbols and markers. Any map you create can be printed on your home printer, or you can export a huge (8000x8000 pixel) image file to send to a print shop to make a wall-size map for your ranch or hunting lease.

Download the 30 day free demo of ExpertGPS and give it a try. If you have any questions about using ExpertGPS for ranch mapping, hunting, or mapping your property, I'm always here to help.

Tom H. asks:
I need a software mapping program that will allow me to draw a circle of varying radius and tell me how many acres in that circle.

How do I Draw a Circle on a Map and Calculate its Acreage?

The formula for the area of a circle is: Area = π * radius². If the radius is given in feet, the area is in square feet. To convert from square feet to acres, divide by 43560. So the acreage of a circular area is: Acres = π * radius_in_feet² / 43560.

Acreage Calculator for a Circular Field

Drawing Circles on the Map

ExpertGPS can draw a circle of any radius around a waypoint. Edit the waypoint, and enter the circle radius in the Proximity field. Waypoint Proximity is used by some Garmin GPS receivers to sound an alarm when you come within the proximity distance. Mariners use proximity waypoints to mark rocks, wrecks, and other obstructions in the waterway, so that their GPS will alert them if they approach these hazards too closely. You can make use of the Proximity circles in ExpertGPS to map out center-pivot irrigation systems for your farm, check the coverage of wireless or communications towers, or determine the service area of a store or business, fire station, or police station.

Related Topics Ask the GPS Expert: How do I calculate the acreage of an irregularly-shaped farm field? Calculating the acreage of any parcel with ExpertGPS. ExpertGPS Help File: Calculating Area

Dan M. from Indianapolis asks:
You claim that your software can calculate an area. This is the application I need because I have a GPS receiver that does not calculate area but if I understand correctly I can mark different waypoints in my farm (not a perfect square) and then download them to your software and then I get the area? Do I need a topo map of my farm to do this???
Please forgive my ignorance but I just need an application that would allow me to know exactly the area in a big farm that may have for example, corn or soy, etc.
Thank you in advance for your help.

How do I Calculate the Area of a Farm Field?

You can use ExpertGPS to calculate the area of any field on your farm, and you don't need your own topo map (or even a GPS receiver) to do this. ExpertGPS will automatically calculate the area of any object you draw on the map or mark with your GPS. Let's start by drawing on the map...

Calculating Area by Drawing on the Map

The first step is to bring up an aerial photo of your farm. Download and install ExpertGPS, and start the program. Click Go to Address on the Go menu, and type in the address of your farm. ExpertGPS will recenter the topo map on your farm. Click Show Aerial Photo Map on the View menu, which should give you a pretty good view of your fields.

Now we're going to trace a field. Select the Track tool. Click once on the corner of your field, and continue clicking at each corner, working your way around the field. The track tool draws straight lines when you click. If there's an irregular edge, along a road or creek, click and drag the mouse, tracing that edge. When you've traced your way around the entire field, press Enter to finish the track. Name your field, and click OK.

Now switch to the Select tool, and click on the track of your field to select it. Right-click, and click Close Track. This tells ExpertGPS to treat this object as a closed shape. You'd use this command any time you were drawing a field, paddock, or stock pond.

On the left side of the screen, switch to the Track List. Click Select List Columns on the View menu, and make sure Area is checked. ExpertGPS will calculate the area of your field (and all the other closed tracks in the Track List) and display it. If you need to switch between acres, square feet, hectares, or other units of measure, click Preferences on the Edit menu, and change the Distance Units.

Calculating Area from a Recorded GPS Tracklog

Another way you could trace the boundaries of your field would be to take your GPS out and walk or drive the edge of the field, recording a GPS track. Back at your computer, click Receive from GPS, and ExpertGPS will bring in the track outlining your field. Follow the directions above, starting with Close Track.

Calculating Area of a Field Marked with Waypoints

If you have previously used your GPS to mark waypoints at the corners of your field, click Receive from GPS to bring them into ExpertGPS. Switch to the Route Tool, and click on each waypoint to connect them together into a route which traces the boundaries of the field. When you are done, select and right-click on the route, and click Close Route. Proceed as above to enable the Area column on the Route List.

Labelling Objects on the Map with their Area

Update - December 17, 2008: ExpertGPS User Bob C. asked a follow-up question: "How can I label an object on the map with it's area?" Here's what I did: I looked in the Area column in the Track list (as described above) to find the area that ExpertGPS calculated for that field. I then selected the field, clicked Edit Track, and entered Field 3n7.9 Acres in the field's Label. The n is a special command that causes ExpertGPS to insert a newline, making Field 3 and 7.9 Acres appear on two separate lines.

Related Topics Ask the GPS Expert: How do I determine the acreage of a field covered by a center-pivot irrigator? How do I calculate area with a GPS? ExpertGPS Help File: Calculating Area