Joseph Elfelt Profile picture
Developer of https://t.co/EAsPQUzuyY, a general purpose web map that can display GIS data. Developer of https://t.co/CK0me4eSZa. Owner of https://t.co/N0NBkZU1OM.
Gertrude George Profile picture 2 added to My Authors
18 Oct
1/7 This tweet thread describes the authoritative USA county-level *daily count* COVID-19 data that is hosted on my server and which can be used by anyone for any non-commercial purpose. #COVID19 #COVID #CovidData
2/7 #JohnsHopkinsUniversity is widely regarded as one of the primary sources for authoritative COVID-19 data. Hopkins curates this data from various sources and hosts it on GitHub at
github.com/CSSEGISandData…
3/7 The #JohnsHopkins “timeseries” data is a *cumulative count* of cases and deaths. My code automatically runs each night and converts those cumulative counts into *daily counts*. I am hosting this daily count data in separate csv files per month.
Read 8 tweets
17 Oct
1/14 I have been volunteering to produce online wildland fire maps for about the last 10 years. This is a multi-part tweet to help people understand satellite hotspot data for wildland fires.
2/14 The #1 thing to know is that any fire data you see on maps is **not real time**. After a satellite pass it takes NASA ~3 hours to process the raw data before it can be displayed on any map.
3/14 Since data you see via an online map is **not real time**, never rely on any map (or anything else) to ignore an order to evacuate. The professionals that make decisions which areas must evacuate have more information than is available to you.
Read 15 tweets
28 Sep
1/6 I’ve been volunteering to produce online wildland fire maps for about the last 10 years. The #1 thing to know is that any fire data you see on maps is **not real time**. There are 2 MODIS satellites and 2 VIIRS satellites. #GlassFire #GlassIncident #ZoggFire
2/6 The MODIS/VIIRS satellites make a total of 8 passes per 24 hours. For the West Coast very rough timing is midnight to 3am (4 passes) and noon to 3pm (4 passes). It takes NASA ~3 hours to process the raw data before it can be displayed on any map.
3/6 Usually by 7am pacific time the maps are showing all the MODIS/VIIRS data that is available until sometime after 3pm. Hotspot locations are approximate and sometimes the data is ‘false positive’.
Read 6 tweets
22 Aug
1/9 Here is a tip that can save a life (yours?) in an emergency. When you call 911 they might not know where you are unless you tell them. I developed #FindMeSAR as a public service project to help solve this problem. #SearchAndRescue #EmergencyManagement Image
2/9 #FindMeSAR (findmesar.com) is a webpage that uses the GPS in your phone to display your coordinates and accuracy value. Several coordinate formats are supported and each one has a different colored screen.
3/9 The yellow screen displays your location in latitude longitude, decimal degrees. This format is used by all 911 call centers.
Read 10 tweets
18 Aug
1/9 What happens if the #ElectoralCollege vote is a tie? Here is a website that lists 64 different ways that could happen:
270towin.com/electoral-coll…

If there is a tie then we might wind up with President Biden and Trump’s running mate as Vice President.
2/9 In case of #ElectoralCollege tie the 12th Amendment says the House elects the President with each state getting *one* vote and the Senate elects the Vice President with all 100 Senators voting. Link to 12th amendment:
constitution.findlaw.com/amendment12.ht…
3/9 Since a majority of Senators are Rs the senate would quickly vote in favor of Trump’s running mate to be Vice President. Boom! That’s a done deal.
Read 9 tweets
18 Aug
1/4 If you zoom out any of the fire maps I post then you will always see all the current satellite hotspot data. That data is automatically updated several times per day. MODIS = red triangle. VIIRS = orange square.

Open #GISsurfer map: bit.ly/3h8oKCF Image
2/4 Caution! Satellite hotspot data is *always* several hours old when you see it on a map and locations are approximate. Never rely on any map to ignore an order to evacuate!
3/4 To make your own custom map link, zoom in on an area or click Menu ==> Search. Turn on the overlay layers you want. Then click Menu ==> Link to this map. The link you see will replicate the map on your screen.
Read 4 tweets
2 Aug
1/6 Here is one of my public service projects that might help to save a life. #FindMeSAR (findmesar.com) is a webpage that uses the GPS in your phone to display your coordinates and accuracy value. #SearchAndRescue #Hiking #10Essential Image
2/6 Several coordinate formats are supported and each has a different colored screen. The yellow screen displays your location in latitude longitude, decimal degrees. This format is used by all 911 call centers.
3/6 When you open FindMeSAR the first time your phone has to be online. The code for this webpage is saved in a special part of the browser's memory and this webpage will then work offline. (Service worker + AppCache)
Read 6 tweets
23 Jul
1/7 Each day #JohnsHopkins publishes *cumulative* counts of #COVID19 cases for each county in the USA. As a public service I wrote code to convert that cumulative count data into *daily* counts for all USA counties. #CovidData #Covid19Data
2/7 This daily count data is in one csv file per month. There is one set of files with daily *case* counts and another set of files with daily *death* counts. Anyone can download and use this data. The only limitation is no commercial use.
3/7 These files include a latitude longitude centroid for each county and will be easy to import into spreadsheet or #GIS software. Each night the count of new #COVID cases for the prior day is added to the current monthly csv file.
Read 7 tweets
19 Jul
1/5 Here are links to csv files with *daily* counts of new #COVID19 cases and deaths for all USA counties. These daily counts begin March 24 and are updated each night just after midnight Pacific time with the counts for the prior day. #CovidData Image
2/5 Each day #JohnsHopkins publishes updated timeseries *cumulative* counts of new cases and deaths for all USA counties. As a public service I wrote code to convert that cumulative count data into *daily* counts. Non-commercial use only.
3/5 The daily count data is in one csv file per month for cases and one csv file per month for deaths. These files include a latitude longitude centroid for each county and will be easy to import into spreadsheet or #GIS software.
Read 5 tweets
18 Jun
1/4 Each day #JohnsHopkins publishes updated *cumulative* counts of #COVID19 cases for each county in the USA. As a public service I wrote code to convert that cumulative count data into *daily* counts. This daily count data can be used for any non-commercial use. Image
2/4 The daily count data is in one csv file per month. These files include a latitude longitude centroid for each county and will be easy to import into spreadsheet or #GIS software. Each night the count of new cases for the prior day is added to the current csv file.
3/4 Here is the link for the March file (data starts on 24th). To download the csv files for April, May and June simply change the number of the month in the download link.
mappingsupport.com/p2/disaster/co…
Read 4 tweets
10 Jun
1/2 #JohnsHopkins is doing a great job posting *cumulative* COVID19 case counts. I developed code that runs each night and converts that data into *daily* counts of new cases. Anyone is welcome to download this data and use it for any non-commercial purpose. Image
2/2 The daily counts of new COVID19 cases are in one csv file per month starting March (data starts on the 24th). Below is an example download link.
mappingsupport.com/p2/disaster/co…
Oopsie - someone found an error in the COVID19 csv files I posted yesterday. When I get that fixed I will post again.
Read 4 tweets
22 Apr
1/4 Are COVID-19 cases/deaths increasing or decreasing over the last 14 or last 7 days in your county or state? This interactive map uses authoritative data from Johns Hopkins to give you the answer. Need help? Click “Map tips”.

Open #GISsurfer map: bit.ly/2Vr25Jk Image
2/4 Each location on the map has two symbols. Circle = prior 14 days. Triangle = prior 7 days. Red = count is trending up. Green = count is trending down.
3/4 The map has several COVID-19 overlays you can turn on/off. When the map opens the overlay “County bad trend in deaths” is ‘on’. Each symbol is a county where the number of deaths over the prior 7 days is trending up.
Read 4 tweets
23 Mar
1/4 Are you a #bored #student or #teacher? Do you like #maps #geography #GIS? Consider taking a look at #GISsurfer which is a general purpose web map I developed. This project is a public service and part of my way to “pay it forward”.

Homepage: gissurfer.com Image
2/4 Government agencies host all kinds of GIS data. Anyone can use GISsurfer to look at that data almost as easy as you surf the internet. No GIS savvy required! You can add GIS data to the map and then save a link that will display your map. Image
3/4 Tip: The detailed documentation is in several PDF files that are linked near the top of the ‘Help’ page. To see some maps I made, click Menu ==> GISsurfer special maps ==> scroll down. Note the “Map tips” link in upper left corner. Image
Read 4 tweets
31 Jan
1/7 Curated list of 3,500+ government #ArcGIS server addresses. All links tested once per week and bad links fixed or flagged. These are ArcGIS servers, not 'portals'.
#URISA #fedGIS #GIS #GISP #GeoSpatial #ESRI #MAPPS @GISLounge @directionsmag
Open PDF:
mappingsupport.com/p/surf_gis/lis… Image
2/7 @server Admins: If my list says “not https” or “SSL problem” then you can fix that with a free SSL certificate from letsencrypt.org. My domains use these. The “SSL problem” tag in the curated server list means Firefox found something wrong with your SSL certificate.
3/7 To find data quickly on an ArcGIS try a Google advanced search. For example, to find trail layers search on:
trails site:____
Replace the underline with an ArcGIS server address.
Read 7 tweets
28 Oct 19
1/7 Short series of posts to help you understand the satellite hotspot data that you see on fire maps. Number 1 rule: Never rely on any map to ignore an order to evacuate. If you are ordered to evacuate you need to collect any pets you have and be gone.
#KincadeFire #GettyFire
2/7 There are three satellites that collect hotspot data, 2-MODIS, 1-VIIRS. Usually any given fire will have a total of 4-6 ‘looks’ per 24 hours. It usually takes NASA ~3 hours to process the raw data before it can be seen on any map. Thus, it is *never* ‘real time’.
3/7 Satellite hotspot data on a map is almost always 3-9 hours old. <== Big reason to not rely on any map to ignore an order to evacuate. Also, the data is not perfect. A grassy area might burn and cool before the next satellite pass and never be detected as a hotspot.
Read 7 tweets
26 Oct 19
1/4
Anyone can make their own custom #GISsurfer map to see near real time wind data.
1. Open GISsurfer with no layers bit.ly/2pfeMtq.
2. Drag and zoom to your area of interest. Or do Menu ==> Search
#DiabloWind #DiabloWinds #KincadeFire #TickFire
2/4
3. Turn on one of the wind gust or wind speed layers. Click the basemap button (next to “Menu” button), look under “Overlay” heading (mobile users scroll down), click layer to turn it on/off.
4. To stay oriented, turn on: ESRI roads and labels, County, State boundary.
3/4
5. Turn on: NOAA weather observations. Zoom out if you do not see any red stars.
6. Click Menu ==> Link to this map.
That link will replicate the map on your screen
Read 5 tweets
25 Oct 19
1/12 Any reporters here? I have a story for you related to fires and all other emergencies. When a cell phone is used to call 911 the call center (PSAP) always gets "Phase 1" coordinates which is the location of the cell tower. Caller might be several miles away. #KincadeFire
2/12 The PSAP *might* get "Phase 2" coordinates and an uncertainty value (i.e. accuracy). Guess what? Those coordinates are intentionally dumbed-down compared to the coordinates the caller's phone can produce. <== No one knows this! #TickFire
3/12 Do this Google search: congress 911 glonass
The USA has a satellite constellation (GPS) and Russia has a satellite constellation (GLONASS). Starting with the iPhone 4s most cell phones use data from both sets of satellites to determine coordinates.
Read 12 tweets
16 Jun 19
1/4 Why is perimeter data on the #Inciweb fire map out-of-date? The Inciweb map simply displays perimeter data that is hosted on the GeoMAC #GIS server. Why doesn’t the GeoMAC server have current perimeter data? #WAfire #ORfire #CAfire #AZfire #COfire #MTfire #GeoSpatial
2/4 For most big fires there usually is a nighttime overflight with infrared sensing gear. Experts analyze that data and determine a new fire perimeter. They also determine areas of intense, scattered and isolated heat. That data is then hosted on the public NIFC FTP server.
3/4 That new fire perimeter eventually shows up on the GeoMAC server and will then appear on the Inciweb map. The problem is that it seems to take a day or more for that perimeter data to go from the NIFC server to the GeoMAC server. Surely that process could be speeded up.
Read 4 tweets
8 Apr 19
1/7 When you call 9-1-1 with a smartphone the wireless carrier is supposed to provide 911 with your coordinates. However, the FCC allows carriers to *exempt themselves* from this requirement simply by filing a form. Think this does not affect you? Wrong! #emergency #dispatcher
2/7 All wireless providers are required to handle *all* 911 calls. If your own wireless provider cannot handle your life-or-death 9-1-1 call for any reason, then your call might be handled by a wireless carrier that does not provide your coordinates to 911.
3/7 The Colorado 911 Resource Center maintains a spreadsheet that shows the self-exemptions wireless carriers have filed with the FCC. Go to sites.google.com/a/co911rc.org/…, scroll down a bit to the “Outdoor rules” section and look for the “Click here” link.
Read 7 tweets