How to Count Houses on Map.

How to Count Houses on Map

How to Count Houses on Map. Counting houses using digital maps allows us to easily make estimations for business case analysis, other humanitarian and social uses cases that require its application. We need to know how to quickly count houses or buildings on a map.

The ability to counts buildings across Africa or other natural disaster zones is useful to be able to assess the number of buildings or households affected. To be able to estimate the humanitarian services requirements and level of demand for social amenities.

Free Digital Maps to Count Houses 

Techniques and Technologies

  • Open Building ( you can Explore, FAQ, Data format, Download)
  • OpenStreetMap(OSM) data from Python and Overpass Turbo API
    • Using Overpass Turbo ( Challenges In Africa – This map intentionally left blank, (received empty dataset))
    • Using Python library called overpy that allows executing Overpass queries from Python
  • Satellite imagery (high resolution households) and use a Computer Vision(CV) algorithm to count the houses.

Counting Houses or Building on Satellite Imagery

Use-case: Counting Buildings in an Area Using Overpass Turbo

  • Overpass Turbo API uses OSM stored data for analysis
  • The OSM stored data is encoded as elements on their maps and expressed using a collection of points, each one with a single latitude and longitude;
    • Nodes are individual points generally used to mark places such as individual shops.
    • Ways are sets of points that describe shapes of buildings, roads etc. it is generally an in depth distinguishing description of node points.
  • To start the analysis process with, we only need two details: location and radius.
    • Location is expressed in geographic coordinates, namely latitude and longitude
    • In case you start with an address or a name of a place, you’ll need to perform a process called geocoding first, i.e. changing it to geographic coordinates.
  • We will generally be interested in nodes (especially with tags) rather than ways because nodes are usually enough when it comes to counting buildings.
  • Counting by category: you can also count by categories using Map Features which are identified as;
    • Categories (keys) and sub-categories (values) and using them we can filter the nodes based on which buildings we’re interested in 
    • Examples; building = retail’, ‘building = supermarket’ , ‘healthcare = pharmacy’, “amenity”=”restaurant”

Noteworthy for Africa on How to Count Houses on Map:

  • Limitation for Africa : Insufficient or no well defined data about their cities, nodes and ways points.
  • Counting of houses in most African regions is almost impossible because building or house node data has not been geocoded on Open Street Map (OSM).

Overpass API vs Google Maps Places API (Nearby Search Request)

  • Google API it’s paid (Overpass API is completely free)
  • it only supports very few categories of places, significantly less than Overpass (it can be partially solved by using correct keywords), 
  • it only returns up to 60 results (spread across several pages), which frequently is way too few to count all relevant places.

How to Count Houses on Map: Example Using Overpass Turbo Web App (View Link)

How to Count Houses on Map
How to Count Houses on Map

Example of Overpass Turbo Query Code

/*
This has been generated by the overpass-turbo wizard.
The original search was:
“building=house”
*/
[out:json][timeout:25];
// gather results
(
  // query part for: “building=house”
  node["building"]({{bbox}});
  way["building"]({{bbox}});
  relation["building"="house"]({{bbox}});
);
// print results
out body;
>;
out skel qt;

Google Earth Engine 

  • Earth Engine GCP
    • A planetary-scale platform for Earth science data & analysis. Geospatial data processing and analysis platform. Powered by Google’s cloud infrastructure.
    • Google Earth Engine combines a multi-petabyte catalog of satellite imagery and geospatial datasets with planetary-scale analysis capabilities. 
    • Scientists, researchers, and developers use Earth Engine to detect changes, map trends, and quantify differences on the Earth’s surface. 
    • It involves satellite imagery, your algorithms and real world applications or use cases
    • Earth Engine is now available for commercial use, and remains free for academic and research use. 
    • Meet Earth Engine (Watch Now) 

Insights for a more sustainable world, powered by Earth Engine.

Understand and tackle critical sustainability and climate issues such as deforestation, water management and sustainable land use.

Our Interest in Google Earth EngineDo some house counts to get to understand social amenities resource demands, get to familiarize with the possibilities of how to use it for knowledge discovery and content related to earth science, as well as data analytics projects for good in my community. Also teach others about its usefulness to research.

Notes On Solutions and Limitations

  • The OpenStreetMap solution did not work because we have mostly unstructured data representations of Africa on the map. (Tool Guide)
  • Estimating Number of Houses – A better metric is the number of households that can afford your service/product at a price point and statistical distribution. You could ballpark your number by taking population density and dividing it by average household size to get an estimate of households per area and then divide by area of interest.( Source )
  • Download high resolution households satellite imagery and use a Computer Vision(CV) algorithm to count the houses.

Related Resources 

earthquake-tremors-in-Nigeria-seefinish-insights

Earthquakes and Tremors in Nigeria

Earthquakes and Tremors in the Nigeria Basin

Recently in Nigeria, a report of a minor tremor earthquake was recorded by the Obafemi Awolowo University monitoring station with a magnitude of 2.6. This earthquake was observed to be associated with the Ifewara-Zungeru Transcurrent Fault Zone system, in South-West Nigeria. The estimated epicentral distance of the tremor was between 108 and 113 km away from the measuring station at OAU Ile-Ife. The epicenter was somewhere along the NW-SE direction of Ile-Ife, Osun State, Nigeria roughly placed close to Omu-Aran in North-Central Kwara State. (3) 

How many incidents have occurred in the last 10 years?

In Nigeria records of earthquakes and tremors in the last 10 years have barely been up to seven (7) as the data below shows. Nigeria has so far recorded over 38 earthquakes and tremors from 1933-01-01 to 2021-07-05. We have collated all data from multiple reliable sources that prove it. Kindly contact us at our email [email protected] for the purchase of data.

Date (year-month-day)Origin timeFelt areasIntensity/magnitudeProbable epicenterLatitudeLongitude
2011-11-050:00:00Abeokuta4.4Close to Abeokuta7.172175153.300487985
2016-07-100:00:00Saki4Oyo8.6590054833.387435805
2016-08-100:00:00Bayelsa and Rivers states3Igbogene (Ogbogene)5.0355394896.402825827
2016-09-110:00:00Kwoi3.1Kaduna9.4477359288.010083644
2016-09-120:00:00Samban Dagi (Sambang Dagi)3Kaduna9.597650378.038932996
2018-09-052:30Abuja, Gitata in Nasarawa3.5Mpape Hills, Abuja9.121852697.485772824
2021-07-0511:11:25Abuja, SW2.6NW-SE direction of Ile-Ife, Osun State, Nigeria roughly placed close to Omu-Aran in North-Central Kwara State.8.2066898585.119414106
10 Years Data on Earthquakes and Tremors in Nigeria

Map Earthquakes and Tremors in the Nigeria Basin

Interactive Maps and Locations and Dates and images

Map of Nigeria showing the study area, the Zungeru-Ifewara fault line

Map of Nigeria showing the study area, the Zungeru-Ifewara fault and some major towns along the fault line.
Map of Nigeria showing the study area, the Zungeru-Ifewara fault, and some major towns along the fault line (view source).

How Prepared Are We in Nigeria for Earthquakes?

What does it mean to be earthquake or tremor prepared, lessons from other countries on earthquakes disaster preparedness means to have the following in place:

  • Monitoring centers located in multiple or specific locations within a country with public access to data reports on predetermined fault zones as presented by Geophysicist and Geophysical surveys.
  • Learn the safe spots in each room of your home. A safe spot may be underneath a sturdy table away from walls or underneath your covers with a pillow over your head if you are already in bed. During an earthquake, most deaths and injuries are caused by collapsing building materials and heavy falling objects.
  • Plan and practice what to do if an earthquake strikes. This will help you easily coordinate when an earthquake occurs.
  • Create an evacuation plan to evacuate a damaged area afterward. Mark where your emergency supply kit (i.e fire extinguishers, food supplies, first-aid package, An ax, shovel, broom, A rope for towing or rescue, Sturdy shoes, hard gloves), locate and turn off switches and values if possible.

How are Earthquakes Measured?

Earthquakes and tremors are measured using Richter Magnitude Scale (shown below)

When should we start getting worried about Earthquakes and Tremors in the Nigeria Basin

First, you need to understand the science of earthquake dictation and prediction. The data capture so far on tremors and earthquakes in Nigeria in comparison to other countries shows that we have had relatively low magnitudes. You can start getting worried when the magnitude goes above 5 on the scale.

Other Potential Natural Disasters

The are many natural disasters and associated health hazards in the world, those that should be of concern to Nigeria are;

  • Flooding 
  • Earthquake 
  • Drought 
  • Volcanic Eruption
  • Landslides or Mudslides
  • Lightning 
  • Extreme Heats
  • Wildfires
  • Tornadoes

Related Resources to Earthquakes and Tremors in the Nigeria Basin

  1. Richter Magnitude Scale?
  2. Preparing for an Earthquake
  3. Nigerian State Records Earth Tremor Measuring 2.6 On Richter Scale
  4. Investigating Earthquake Magnitude By Seismic Signals And Wavelet Transform In Optimal Design
  5. Nigeria authorities dispel earthquake fears after Abuja tremors
  6. A review of earthquake occurrences and observations in Nigeria (pdf download)
  7. Preliminary investigation of earth tremors using total electron content: a case study in parts of Nigeria (VIew Alternate Source)
  8. Preliminary geological evidence for multiple tremors in Kwoi, Central Nigeria
  9. 92 earthquakes and tremors recorded in past 24 hours around Mount Nyiragongo volcano
  10. African Risk Capacity Group and Centre for Disaster Protection seal collaborative deal to improve disaster risk management systems – World – ReliefWeb
  11. Review Of Earthquakes In Nigeria: An Understudied Area
  12. Mechanical Model for Nigerian Intraplate Earth Tremors

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