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November 2022 update
Earlier this year I released the first version of GeoJPG. However, as I learned more about developing Progressive Web Apps (PWA) I realized that this first version was more in the nature of a proof-of-concept showing that a web map can be installed on a mobile device and then work offline. Initially I planned to release GeoJPG v2 at the same time that GISsurfer v3 is released. But as the summer and then fall weeks ticked by, I changed my mind. The good news is that the core features of GeoJPG v2 are working fine in the current beta. However there still is work to do, including documentation, before this update is ready to be released.
GeoJPG is a new type of web map. First, the user can install this web map so it works offline on both iOS and Android devices.. Second, the user can customize the map to show just about any GIS data the user wants to see.
Each map is one or more georeferenced JPGs. Each JPG can cover either a fairly small area or several hundred square miles. The user can specify which layers of GIS data they want to have 'baked' into each JPG. This GIS data can come from almost any ArcGIS server.
"Georeference" means that you know the latitude and longitude for the area covered by the JPG image. A new feature in GISsurfer makes it super easy for anyone to take a series of screenshots while shifting the map exactly one screen worth up/down/left/right. Each screenshot is 100% map. GISsurfer reports the georeference data for each screenshot and also for the outer boundary of a series of adjoining screenshots.
For step-by-step documentation showing how to use GISsurfer to make georeferenced JPGs, please see the GISsurfer Help page and scroll down just a bit to the section listing several PDF files.
This is a consulting service that produces the most accurate property corner coordinates you can get without buying a survey. Clients email me information about their property. I process that information with software I developed and produce a custom map that displays the client's approximate property lines and corner locations on an aerial basemap.
Clients can open their map with a smartphone or tablet and then turn on a geolocation feature that will show where they are as they walk around. When geolocation is turned 'on' the GPS accuracy value is displayed and constantly updated. The map can work either online or offline on both iOS and Android devices.
Common uses for this service include finding 'lost' survey stakes, marketing property that is for sale, making a good faith effort to hunt only on your own land, locating the approximate corners of unsurveyed land, etc.
If you are using the map online then contour lines can be displayed on top of the aerial and you can change the basemap to the USGS topographic map.
Please keep in mind that the corner coordinates and property line data this service produces are approximate and are not a survey. If you need to know exactly where your property lines are located please contact a surveyor.
For more information about this service please see:
Mobile users - FindPropertyLines.com
Non-mobile users - PropertyLineMaps.com
Johns Hopkins University is widely regarded as an authoritative source for COVID-19 data. Each day they update a ‘timeseries' cumulative count of cases and deaths for all counties in the USA. I wrote code that runs each night and (1) converts the Johns Hopkins cumulative counts into daily counts and then (2) converts those daily counts into 7-day-average counts for each of the prior 14 days.
Below is a link to a PDF file that will show you two things. First, anyone can download the COVID-19 daily count data from my server. This data covers all USA counties. Second, two GISsurfer map links are provided so you can see at a glance if the recent number of COVID-19 cases or deaths is increasing or decreasing. One map link is based on the daily count data. The other map link is based on a running 7 day average. Both maps have overlay layers that can display the data by county, by state or totals for the USA.
The csv files with the daily count data and the GISsurfer maps are automatically updated each night. These resources are made available as a public service and are free for all to use. The only limitation is that your use must be non-commercial.
Open PDF file:
For a number of years I have volunteered to produced interactive maps of wildland fires. These maps are displayed by GISsurfer and feature a number of GIS overlays that the user can turn on/off. Each map always includes the latest MODIS and VIIRS satellite hotspot data. Often for larger fires there is a nighttime infrared overflight. My map uses that data to display the most recent fire perimeter and areas where the fire is burning intensely.
Each map has two links in the upper left corner to help you get the most benefit from the map.
The best place to see these wildland fire maps is the MappingSupport twitter feed:
Here is a PDF file with a list that I curate of 3,000+ addresses for government ArcGIS servers. These servers range from the federal level down to the city level. GISsurfer can display data that is hosted on these servers.
For COVID-19 GIS layers see p.7
Everyone is welcome to share this list. The list is automatically scanned once per week by my own code to ensure that dead links are promptly fixed or flagged. An updated list is usually posted each Wednesday morning.
There is a nice article about this work in the URISA national newsletter. This is an organization of GIS professionals. See page 12.
You do not need to be a GIS professional to benefit from this list of ArcGIS server addresses. Here is a PDF I prepared with step-by-step instructions showing how data can be downloaded from an ArcGIS server and saved as a KMZ file that can be used with ATAK, ITAK, Google Earth and various other programs.
Here is a link to a brief description of the new features in GISsurfer version 3 including the ability to make georeferenced JPG and PNG files that display GIS data.
GISsurfer is a general purpose web map based on the free open-source Leaflet map API (Application Program Interface). It will work on most devices that have a browser. Depending on your device, you will see either a touch-friendly interface or mouse-oriented interface. An easy way to see the various features is to click the 'Menu' button or basemap button and then try the various choices.
In addition to the standard web map features (search, geolocation, save a custom map link and multiple basemaps) GISsurfer has a big impact feature you are unlikely to see on any other web map. You can open GISsurfer and then view data that is hosted on thousands of public-facing (i.e. no login required) GIS (Geographic Information System) servers. No GIS savvy required! You can split the screen and display the table of contents of an ArcGIS server on the left side with the map on the right side. Drill down on the table of contents to a data layer, click the layer and in a few seconds that data appears on the map. Click layer - See data. For more information please visit the GISsurfer homepage (see link below) and click Menu ==> Help and scroll down a short way to the section listing several PDF files.
This link takes you to the GISsurfer homepage.
https://gissurfer.com (You will be redirected)
The following link starts GISsurfer and displays the default map.
In addition to opening GISsurfer and then 'surfing' data that is hosted on GIS servers, you can also make GISsurfer map links with pre-defined GIS overlay layers that can be turned on/off and restacked on the map. Below are links to a few GISsurfer maps that I made. Most of these maps 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.
Each of these map links includes a txtfile parameter that points to a txt file that I made. The pre-defined GIS layers the map can display are defined in that txt file. If you are curious to see what that looks like, simply copy the address for any of those txtfiles and paste it into a browser.
In order to learn how to turn GIS overlay layers on/off and get the most benefit from the map, please take a few minutes to open any map and read the "Map tips".
Rain and Flood Map
Wildland Fire Map
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
National Forest Recreation Map
There are GIS overlay layers that show trails, roads, campgrounds and much more.
Bureau of Land Management Recreation Map
This map is zoomed in on an area in Colorado when it opens, but it covers all BLM land.
National Park Recreation Maps
There is now a separate GISsurfer map link for each of the 63 national parks. When you open any of these maps the trails are highlited and will be easy to see on any basemap. You can find these map links on this web page:
NOAA Nautical Charts Map
If you want to see online gridded maps, GISsurfer can help you do so. Three kinds of gridded maps can be displayed.
GISsurfer map with MGRS (Military Grid Reference System) grid
GISsurfer map with USNG (U.S. National Grid) grid
GISsurfer map with UTM (Universal Transverse Mercator) grid
FindMeSAR (https://findmesar.com) 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! Are you curious why Uber can find you but 911 might not be able to find you? Here is a report I prepared that explains the reasons with links to documents on the FCC's website.
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.
Test your cell phone location accuracy
FindMePro (https://findmesar.com/p/findmepro.html) 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.
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.
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.
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.
Big picture most important take home point:
The basic 911 system *does not* make any use of coordinates produced by cell phones. Instead, the 911 system uses coordinates that are intentionally dumbed down and less accurate than the coordinates produced by cell phones. 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.
The last page of this report has links to several related reports. One of them explains why sometimes 911 cannot determine the location of a cell phone unless the caller provides that information. This weakness in the 911 system is the reason why everyone needs some way to use their cell phone to display their coordinates and the equally important accuracy value.
The tips are in this PDF file: