Contact and About

Property Line Maps

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Website - Cell Phone
Website - Desktop
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At Property Line Maps we produce online maps for your cell phone or computer that show your approximate property lines on the Google aerial and on the USGS topographic map. Each client also receives a GPX file with approximate corner coordinates that can be loaded into many handheld GPS units.

If you are reading this on a cell phone or small tablet, then please visit for all the details and to place an order. But if you are reading this on a large tablet or other large screen then we recommend you visit to learn more.

After we process your order, open the email we send you and click or tap the link to open your online map on almost any device from cell phones to desktop computers. If you open your online map with a cell phone then you can turn on a geolocation feature and see where you are as you walk around your land. No cell connection on your land? No worries! We show you how to use your cell phone offline.

Or instead of using a cell phone you can load the GPX file we send you into many Garmin GPS units and find survey stakes or find approximate property lines.

Most single parcels cost $59.98 and include the online map link and GPX file.

Although the property corner coordinates and property lines we produce are approximate, they are still the most accurate coordinates you can get without hiring a surveyor. But if you need to know exactly where your property corners and lines are located, then you will need to hire a surveyor.

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Gmap4 Has Been Shutdown

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Due to policy changes at Google I have shut Gmap4 down except for a few narrow use cases. Due to its popularity Google would have charged me over $1,000 per month to keep Gmap4 going.

The good news is that I am building GISsurfer to replace Gmap4. See the next section for some details.

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GISsurfer is a general purpose map viewing tool that is based on the free open-source Leaflet map API (Application Program Interface). It will work on most devices that have a browser. My intention is that GISsurfer will replicate most of the Gmap4 features. This will include support for USNG coordinates, MGRS coordinates and UTM coordinates.

In addition to the built-in basemaps and overlays, the user will be able to display data that is hosted on hundreds of GIS (Geographical Information System) servers.

This link takes you to the GISsurfer homepage.

The following link starts GISsurfer and displays the default map. See the next section for example GISsurfer maps that display GIS data related to disasters and also recreation.

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GISsurfer Special Maps

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A great many government agencies from the federal to local level are hosting data on public-facing GIS (Geographical Information System) servers. Below are links to a few GISsurfer maps that display some of that data. Most of thes emaps have well over a dozen data overlay layers that you turn on/off and restack. These GIS maps do not display a static file where the data never changes. Instead, each time you open one of these maps or turn on a data overlay layer, the most recent data flows from the GIS server to your screen.

If you click the "Map Tips" link in the upper left corner of a GIS map then you can quickly learn how to (1) turn other GIS overlays on/off, (2) how to display GIS attribute data for the overlay that is "on top", (3) how to make your own custom map link so the map opens the way you want it to look and more useful tips. Also the map legend is usually part of the "Map Tips" page.

Disaster Maps

Rain and Flood Map,-98.525391&zoom=4&basemap=USA_basemap&overlay=Weather_watch_warning&txtfile=

Wildland Fire Map,-111.533203&zoom=5&basemap=USA_basemap&overlay=VIIRS_24_hours,MODIS_24_hours&txtfile=

For some of the larger fires I also produce a daily map that shows the latest fire perimeter. This perimeter data is produced by fire staff that analyze infrared data collected by a nighttime overflight. The best place to see those map links is the MappingSupport Twitter feed

Recreation Maps

National Forest Recreation Map,-121.550976&zoom=14&basemap=USA_basemap&overlay=Trail_yellow,Trail&txtfile=

National Park maps
A project is underway to produce a GISsurfer map link for each national park. To see which parks already have a GISsurfer map link and to look at those maps, open GISsurfer then click Menu ==> "GISsurfer special maps" and scroll down.

NOAA Nautical Charts Map,-97.294922&zoom=4&basemap=NOAA_nautical_charts&txtfile=

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1,700+ Government ArcGIS Servers

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Here is a PDF file with a list that I curate of 1,700+ addresses for government ArcGIS servers. These servers range from the federal level down to the city level. Everyone is welcome to share this list however they see fit. This list is automatically scanned once per week by my own code to ensure that dead links are promptly fixed or removed.

Sneak peek: The GISsurfer browser map I am developing will let anyone surf data on ArcGIS servers almost as easily as you surf the internet. That feature was done with beta testing via Gmap4 and just about to get promoted into the production code when I shut Gmap4 down. I am looking forward to adding this feature to GISsurfer but have some other work to finish first. You will be able to display the table of contents for a GIS server on one side of your screen and the map on the other part of your screen. Click a layer in the table of contents and that data will appear on the map.

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FindMeSAR ( ) is a browser app for smartphones that displays the user's coordinates and accuracy value. Within 30 seconds many users will see an accuracy value of about 5 meters (~16 1/2 feet).

The "Next Format" button will scroll through four coordinate formats. Each one has a different colored screen.

Tip: If you call or text 911 then the dispatcher might not know your location unless you tell them! Everyone with a cell phone needs a super easy way to display their coordinates and accuracy value in a stressful emergency situation. Whether you have FindMeSAR or a similar app on your phone is not important. What is important is that everyone have an app that easily and quickly displays (1) their coordinates in decimal degrees and (2) the accuracy value.

How to make FindMeSAR ready for when you need it in a hurry:
1. Open FindMeSAR
2. Tap the "Next Format" button until the yellow screen appears. This screen shows your coordinates in decimal degrees which is the format used by 911 dispatchers.
3. Save the app's icon on your home screen.

When you tap the icon to open the app, it will automatically display the yellow screen. If you provide your coordinates to 911, then also be certain to give the equally important accuracy value.

To learn more about the app and get additional tips, please open FindMeSAR and tap the About button.

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Test your cell phone location accuracy
FindMePro is a browser app that anyone can use to find out which settings on their cell phone or tablet produce the most accurate latitude longitude coordinates showing their location. I produced this browser app after discovering that my iPhone 4s sometimes produces coordinates with a good accuracy value but which in reality are wrong by several miles.

While you can try FindMePro on desktop and laptop computers, typically the accuracy will be very poor. FindMePro is intended to run in browsers on cell phones and tablets.

This app lets you:
1. Ask your browser to keep giving you your location coordinates while improving the accuracy.
2. Display the details for each set of coordinates on your screen.
3. Display each location on the Google aerial. Smaller circles indicate more accurate coordinates than bigger circles.
4. Adjust certain settings that are used by the app. For example, you could ask your browser to give you just a single coordinate instead of a stream of coordinates.

Open FindMePro

Typically when you tell this app to start collecting data the first locations returned are not very accurate and result in big circles on the map. Fairly quickly the accuracy should improve until the circles have about a 5 meter radius.

About button
The app’s “About” button has more information on how you can test your cell phone to find out which settings on your phone produce the best and worst coordinate data.

Crowd sourced buttons
The two "Crowd Sourced" buttons have information on sharing your results so we all learn how to get the most accurate coordinates from our phones and how to recognize bad coordinates.

Two reasons for poor coordinate accuracy
First, certain settings on your phone can influence the accuracy of the coordinates your phone produces. Please read the text under the "About" button for suggestions on which settings you might want to test. Second, FindMePro tells your browser to only report coordinates for your current location and to *not* report any cached coordinates for any prior location. Some (all?) browsers ignore this instruction and sometimes report cached coordinates that can be wrong by several miles. For more information tap the "Crowd Sourced Results" button.

How to compare coordinates produced by other apps
1. Use FindMePro to collect coordinate data and display the map.
2. Tap Menu ==> Search
3. Enter coordinates from any other app into search bar at the top of the screen.
4. Tap Go
The map will center at the coordinate you enter. You can see how, that location compares to the green circles (last three coordinates) produced by FindMePro.

Offline use
Currently FindMePro only works if you are online. The browser technology needed to implement offline use is currently undergoing a major change (from 'appcache' to 'service workers'). After most browsers implement this new technology and it is stable, then support for offline use will be added to FindMePro.

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Calling 911 With a Cell Phone
Tips That Might Save Your Life

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Big picture most important take home point:
The 911 system does not make any use of the coordinates produced by your cell phone. Instead, the 911 system uses coordinates that are intentionally dumbed down and less accurate than the coordinates produced by your phone. In short, Uber uses more accurate coordinates to give you a ride than 911 uses to try and save your life.

These tips for calling 911 with a cell phone were developed in part after an extensive review of documents on the FCC website. In addition, input was received by people working in the telcom industry.

Among other things you will learn why it is important to try calling 911 even if your phone says 'no service' and why everyone needs an app on their phone that will display their coordinates and the equally important accuracy value.

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