Showing posts with label GIS. Show all posts
Showing posts with label GIS. Show all posts

Wednesday, 30 December 2015

Using Leaflet.js for making my maps zoomable

I have come across the Javascript library Leaflet.JS which I have begun applying to my maps of Cornwall.

It may be used, in conjuction with Mapbox, to render OpenStreetMap in a number of styles, for example:  link to taklowkernewek.neocities.org.

I have also made one of the versions of my cycling maps of Cornwall zoomable. This is simply done by rendering a 16384x16384px image of the map in QGIS, and then simply using Leaflet.js to make it zoomable, with the assistance of gdal2tiles.py to make the various 256px square tiles needed.

Link: taklowkernewek.neocities.org/mappys/leafletJStest/westcornwall.html

Follow link for zoomable version of this map, and also further maps of mid and east Cornwall.
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Saturday, 19 December 2015

Slope lines from segmented digital elevation model - after upgrade to QGIS 2.12.1

I mentioned previously that I used QGIS to draw lines in the direction of slope, where I had a segmented layerstack which included elevation, slope, aspect and 2 curvature layers (longitudinal and cross-sectional). This was done with RSGISlib in a similar way to my Mars work.

There was an bug with QGIS 2.12 that meant the plotting of arrows didn't work but with QGIS 2.12.1 this seems to be working again. It still takes a long time to render with the SVG marker, even with 32GB RAM and a quad-core system.

Here are a few examples:

Truro area in Cornwall. The slopes are marked with arrowed lines, with steeper slopes marked more thickly, and red for convex, and blue for concave slopes.

A closer zoom into the city.
Around Falmouth, including Pendennis Head
Falmouth again, with grayscale elevation.

Aberystwyth, Ceredigion, Wales:

I show here several QGIS screenshots, at 1:10000 or larger scale, since the rendering of the arrows becomes very slow beyond 1:10000.
Ynys Las and part of Borth Bog (Cors Fochno). This is mainly a flat area so most segments do not have lines shown.
Borth itself, a little to the south
Clarach Bay, and Wallog, and Bow Street

Aberystwyth town and main university campus are here shown, along with Pendinas hillfort, Penparcau, and Llanbadarn Fawr.

Cadair Idris - a textbook glacial landscape

Showing the arrows downslope only.

Adding in the slope parallell lines but making the arrowheads smaller.

At 1:20000 this takes a long time to render on the map canvas in QGIS.
A version with only the lines renders much faster.

Using contours instead of shading to indicate elevation.

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Tuesday, 9 June 2015

Remote Sensing and GIS links page





Some time ago I posted a links page, I have added some more and rearranged it a bit:

Remote Sensing sensors and data:

  • Landsat home page at the US Geological Survey.
  • NASA Landsat Science page.
  • US geological survey Earth Explorer interface for accessing Landsat (and other) satellite data.
  • ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) homepage. ASTER is an imaging instrument onboard Terra, the flagship satellite of NASA's Earth Observing System (EOS).
  • information on TERRASAR-X (Synthetic Aperture Radar satellite).
  • The SPOT series of commercially operated optical high-resolution multispectral satellites.
  • The European Space Agency's Copernicus programme (previously known as the Global Monitoring for Environment and Security programme (GMES)), including the current and upcoming Sentinel series of Earth observation satellites.
  • Including information on the Worldview series of satellites.
  • In 2000, the Space Shuttle flew a radar that produced a digital elevation map of the world. The 1 arcsecond data from that is now available for most of the world, previously only the USA had 1 arcsecond data publicly released, with the data covering the rest of the world released at 3 arcseconds resolution. Since September 2014, the 1 arcsecond data has been released for most of the world.

Earth-based Applications of Remote Sensing and GIS

Planetary Science Applications

Astronomy links

  • On August 21, 2017, millions of people across the United States will see nature's most wondrous spectacle — a total eclipse of the Sun. It is a scene of unimaginable beauty; the Moon completely blocks the Sun, daytime becomes a deep twilight, and the Sun’s corona shimmers in the darkened sky. This is your guide to understand, prepare for, and view this rare celestial event. March 20th 2015 eclipse in Faroe Island and Svalbard.
  • A website that details the passes of the International Space station, Iridium flares and other artificial satellites, as well as providing information on planets etc. visible in the sky.
  • Free planetarium software. The program enables you to draw sky charts, making use of the data in many catalogs of stars and nebulae. In addition the position of planets, asteroids and comets are shown.
  • Solar Eclipse prediction software, which shows the track of the moon's shadow on the Earth, and local circumstances including magnitude, start/end times and duration of totality for eclipses between 13000BC and 16999AD. Also see LmapWin for lunar eclipses.

Remote Sensing and GIS software, tutorials etc.

  • Dan Clewley's blog on open-source remote sensing software.
  • Online access to ArcGIS Help.
  • QGIS project page where you can find the free and open source QGIS software.
  • A self-paced course on free & open source software for geospatial (FOSS4G) applications from the Free and Open Source Software 4 Geo Academy. 5 self-paced courses using QGIS (and a bit of GRASS7) are available.
  • QGIS blog by QGIS developer and data visualisation specialist Anita Graser.
  • A GIS blog containing tips and tutorials on QGIS.
  • Blog by Luca Congedo, the author of the Semi-Automatic Classification Plugin for QGIS that allows for supervised Land Cover classifications.
  • This reference manual details the use of modules distributed with Geographic Resources Analysis Support System (GRASS), an open source (GNU GPLed), image processing and geographic information system (GIS).
  • Carleton University Open Source GIS tutorials.
  • a free and open source program to manage GPS data. This can import data from a GPS device and add map layers from OpenStreetMap and digital elevation model data.
  • GIS information portal.
  • Online converter in Javascript from Lat/Long to OSGB grid references and vice versa.
  • -Downloadable Grid Inquest software from the UK Ordnance Survey to convert between Lat/long and OSGB grid references. An online batch converter is also available.
  • An online database of spatial reference descriptions in a large number of geographic and projected coordinate systems.
  • Flex Projector is a freeware, cross-platform application for creating custom world map projections. The intuitive interface allows users to easily modify dozens of popular world map projections - the possibilities range from slight adjustments to making completely new projections. Flex Projector is intended as a tool for practicing mapmakers and students of cartography.
  • free open source image analysis software.
  • Geomorphons are a pattern recognition method of terrain analysis developed by Tomasz Stepinski and Jaroslaw Jasiewicz. It is available as a Web-based utility that allows users to calculate geomorphons maps from their own DEMs (for smaller datasets) and also as a GRASS7 module. Blog post including video of lecture about it.
  • Written by Prof. Jo Wood, LandSerf is a freely available Geographical Information System (GIS) for the visualisation and analysis of surfaces. Applications include visualisation of landscapes; geomorphological analysis; gaming development; GIS file conversion; map output; archaeological mapping and analysis; surface modelling and many others. It runs on any platform that supports the Java Runtime Environment (Windows, MacOSX, Unix, Linux etc. I used it myself in my dissertation on Martian glaciers.

Python

HTML, CSS and Javascript

Online Mapping

Downloadable GIS data

Cartography and Data Visualisation Advice

Google Fusion Tables

GIS Data visualisation examples

General Mapping Fun

  • a lot of interesting things done with maps. warning: procrastination alert.
  • warning: procrastination alert.
  • A website (in German) with many examples of historical maps, including many examples of the Soviet Union's military maps at 1:500k and 1:1M scale, and among other things maps with various European powers realised as animals (often this is 1st world war propaganda - from all sides).
  • A business based in Cornwall, offering quality cartographic and design services on a contract basis for clients of all sizes.

Travel time maps

LaTeX (Document processing)

Art/Science collaboration

  • by Julian Ruddock. Website showing his projects that are based on art and science collaboration in relation to climate change.

Citizen Science and crowdsourced cloud computing

Games

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Saturday, 14 June 2014

Object-based segmentation of topography with RSGISLib

The RSGISLib (Remote Sensing and GIS) Python library written by Pete Bunting and Daniel Clewley provides a number of features, among them segmentation of images to objects.

This can not only be applied to what one conventionally thinks of as images, but also topographic layers. I thought I'd practice this on Earth first before trying to do this for Mars as I will be for my dissertation.

Using Space Shuttle Radar data (freely available - I got it via the program Viking) I obtained the elevation of the British Isles (excluding Shetland) and using GDAL via QGIS and the command line, created slope and aspect layers. I then transformed the aspect to remove the discontinuity at 360-0 deg, using degrees from N, so that 180 is south facing, east and west are both 90 etc.

Using RSGISLib it is possible to segment to objects. Here I show some results of doing so, using a layerstacked image with elevation, slope and angle from N. I have set the minimum connected object size to 1000 pixels. With the topographic data gridded at 73m, this means objects about 5.5 sq. km or larger.


Visualisation is a gaussian stretch in TuiView, setting red to aspect, green to slope, and blue to elevation, showing mean values for each segment.



Now I show a few of the actual segments without the values, with colours assigned in RSGISLib for visualisation. It is possible to populate a Raster Attribute Table to add data to the segments for a land cover classification.

From the Isles of Scilly to the Isle of Wight:
Wales, and central England.
 Zooming in to mid Wales:

By changing the object size, it is possible to do this at different scales. This is part of the segmentation for a minimum object size of 16384 pixels (that is about 89 sq. km) equivalent to a square 9.5km a side:

The thing that makes geospatial data interesting is how what you see in it changes depending on what scale you look at it and how you visualise it.

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Saturday, 29 March 2014

List of Remote Sensing and GIS links

Here is a list of Remote Sensing and GIS links that may be useful and/or interesting:

Remote Sensing and GIS software, tutorials etc.

 

http://spectraldifferences.wordpress.com/about - Dan Clewley's blog on open-source remote sensing software.

http://resources.arcgis.com/en/help - Online access to ArcGIS Help.

http://opticks.org - Opticks - free open source image analysis software.

http://www.qgis.org - QGIS project page where you can find the free and open source QGIS software.

http://foss4geo.org  - A self-paced course on QGIS from the Free and Open Source Software 4 Geo Academy. There are two modules currently, an introduction and cartography (June 2014) with more coming soon.

http://anitagraser.com - QGIS blog by QGIS developer and data visualisation specialist Anita Graser.

http://infogeoblog.wordpress.com - A GIS blog containing tips and tutorials on QGIS.

http://fromgistors.blogspot.com  Blog by Luca Congedo, the author of the Semi-Automatic Classification Plugin for QGIS that allows for supervised Land Cover classifications.

http://gracilis.carleton.ca/CUOSGwiki Carleton University Open Source GIS tutorials.

http://sourceforge.net/apps/mediawiki/viking/index.php?title=Main_Page - Viking: a free and open source program to manage GPS data. This can import data from a GPS device and add map layers from OpenStreetMap and digital elevation model data.

http://www.gislounge.com GIS information portal.

http://www.movable-type.co.uk/scripts/latlong-gridref.html Online converter in Javascript from Lat/Long to OSGB grid references and vice versa.
http://www.ordnancesurvey.co.uk/business-and-government/help-and-support/navigation-technology/os-net/grid-inquest.html Downloadable Grid Inquest software to convert between Lat/long and OSGB grid references. An online batch converter is also available.

http://www.w3schools.eu/2012/07/webgl-essentials-part-i
Tutorial for WebGL. WebGL is an in-browser 3D renderer based on OpenGL, which lets you display your 3D content directly into an HTML5 page.

 Python:

 

https://www.python.org/doc - The official Python website with online documentation and tutorials.


 http://www.rsgislib.org - Remote Sensing and GIS library: a collection of tools for processing remote sensing and GIS datasets, used via a Python library or XML bindings.

https://bitbucket.org/petebunting/arcsi - ARCSI atmospheric correction software (Python).

http://www.py6s.rtwilson.com - Py6S (Second Simulation of the Satellite Signal in the Solar Spectrum) - a Python library implementing atmospheric correction models.

http://videolectures.net/mloss08_hunter_mat - video lecture on matplotlib (plotting library for Python) by one of its developers (dates from 2008).

a few links from astronomers - some of which may be applicable to remote sensing:
http://python4astronomers.github.io
http://www.astrobetter.com/visualization-fun-with-python-2d-histogram-with-1d-histograms-on-axes

http://geospatialpython.com - Joel Lawhead's Geospatial Python blog.

http://code.google.com/p/pyshp - Python Shapefile library.
http://code.google.com/p/geopy/wiki/GettingStarted geopy - geocoding for python

Online Mapping

 

http://www.openstreetmap.org OpenStreetMap - a free and user-editable online map.
http://www.gravitystorm.co.uk Website of OSM developer Andy Allan.
http://www.ravenfamily.org/andyg/openstreetmap.htm OSM data with topography of UK and Ireland exported for Garmin GPS units.
www.elsewhere.org/journal/gmaptogpx A Javascript tool to export directions as a GPX file from Google Maps.

http://www.perfilderuta.es/perfil.php?lng=en Draw the elevation profile of your bicycle routes.
http://maps.vlasenko.net Soviet military topographic maps.

Downloadable GIS data

 

http://www.ordnancesurvey.co.uk/business-and-government/products/opendata-products.html UK Ordnance Survey Open Data. Various raster and vector layers are available.

http://freegisdata.rtwilson.com - A categorised list of freely available GIS data compiled by Robin Wilson.

Cartography and Data Visualisation Advice

 

http://colorbrewer2.org - Colour Palettes, including selecting palettes to reproduce effectively in print, and for colour-blind viewers.
 http://tools.medialab.sciences-po.fr/iwanthue -  Colours for data scientists. Generate and refine palettes of optimally distinct colors.

http://www.jasondavies.com  Freelance data visualisation consultant Jason Davies' page.

http://earthobservatory.nasa.gov/blogs/elegantfigures NASA blog on data visualisation.

http://visual.ly Data visualisation online community and blog.

http://www.pheelicks.com/2014/03/rendering-large-terrains An example of rendering a large terrain in 3D using WebGL.

http://www.shadedrelief.com Ideas and Techniques about Relief Presentation on Maps. Includes www.shadedrelief.com/cleantopo2 a cleaned of artifacts topographic and bathymetric dataset for cartographic purposes.

GIS Data visualisation examples


http://datashine.org.uk The DataShine mapping platform from the UCL Centre for Advanced Spatial Analysis. Shows a selection of data from the 2011 England and Wales and Cornwall census. The visualisation clips the output polygons to where there are buildings according to OS Opendata vector maps.

General Mapping Fun


https://support.google.com/fusiontables/answer/184641 - how to use Google Fusion tables to make a visualisation of data on a customized Google Map.
http://www.curriculumkernewek.org.uk/map.html - an example that I did much of the coding for.

http://googlemapsmania.blogspot.co.uk - a lot of interesting things done with maps (warning - procrastination alert!).

http://bigthink.com/blogs/strange-maps - Strange Maps (warning - procrastination alert!)

Travel time maps

 

http://property.mapumental.com - find areas within a certain travel time by public transport to a location. This assumes you can walk on water
http://traveltime.propertywide.co.uk similar, allows using different kinds of transport

Remote Sensing data and information on sensors:


http://earthexplorer.usgs.gov US geological survey Earth Explorer interface for accessing Landsat (and other) satellite data.
http://landsat.usgs.gov Landsat home page.
http://landsat.gsfc.nasa.gov NASA Landsat Science page.


http://asterweb.jpl.nasa.gov ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) homepage. ASTER is an imaging instrument onboard Terra, the flagship satellite of NASA's Earth Observing System(EOS) 

 http://www.astrium-geo.com/terrasar-x information on TERRASAR-X (Synthetic aperture radar satellite)

http://www.astrium-geo.com/en/4388-spot-1-to-spot-5-satellite-images
http://www.astrium-geo.com/en/147-spot-6-7-satellite-imagery  SPOT 1 to 7 (optical high-resolution multispectral commercially operated satellites).

http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus  The Copernicus programme (previously known as the Global Monitoring for Environment and Security programme (GMES)), including the current and upcoming Sentinel series of earth observation satellites.

http://www.satimagingcorp.com Website of Satellite Imaging Corporation - including information on Worldview series of satellites.

Earth-based Applications

 

http://www.renewables-atlas.info - The Atlas of UK Marine Renewable Energy Resources.

http://www.quantarctica.org - Quantarctica - A collection of datasets focused on Antarctica for use with QGIS.

http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cg  Arctic Sea-Ice Monitor, by the International Arctic Research Center (IARC) in corporation with the Japan Aerospace Exploration Agency (JAXA) .

http://www.avex-asso.org/dossiers/wordpress/?page_id=2754 A map of (modelled from urbanization) night sky light pollution across Europe. A map of Great Britain can be viewed at http://www.avex-asso.org/dossiers/wordpress/?page_id=127

http://sahultime.monash.edu.au  SahulTime is an ongoing project to create a visual, interactive representation of the Earth's history. Observe the geography of Australasia over the last 120,000 years.

 http://www.zygrib.org Visualization of weather data. The program can download NOAA  (GFS Model) weather forecasts for 8 days ahead for anywhere in the world.

http://www.carbonmap.org - A data visualization project for "Making sense of climate change responsibility and vulnerability", created by Kiln (website with other examples).

Planetary Science Applications

 

http://pds.jpl.nasa.gov NASA Planetary Data System.
http://ode.rsl.wustl.edu  PDS Geosciences Node Orbital Data Explorer, covering Mars, the Moon, Mercury and Venus.
http://mars.jpl.nasa.gov Main NASA Mars page.
http://jmars.mars.asu.edu JMARS is an acronym that stands for Java Mission-planning and Analysis for Remote Sensing. It is a geospatial information system (GIS) developed by ASU's Mars Space Flight Facility to provide mission planning and data-analysis tools to NASA's orbiters, instrument team members, students of all ages, and the general public.
http://www.uahirise.org/hiview HiView is a downloadable software tool, the best way to explore HiRISE (the high resolution imaging instrument on NASA's Mars Reconnaissance Orbiter) images of the Martian surface at the full resolution of the imagery.
http://hrscview.fu-berlin.de/cgi-bin/ion-p?page=entry2.ion  Freie Universität Berlin web interface to the Mars Express High Resolution Stereo Camera image archive.

http://english.cntv.cn/special/lunarmission/index.shtml information on Chang'e 3 Chinese lunar mission.
http://www.spaceflight101.com/change-3.html information on Chang'e 3 Chinese lunar mission.
http://lunar.gsfc.nasa.gov Lunar Reconnaisance Orbiter homepage.

http://saturn.jpl.nasa.gov NASA Cassini Orbiter page.
http://www.ciclops.org/index.php CICLOPS (Cassini Imaging Central Laboratry for Operations) i.e. optical and near infrared imaging.
http://wwwvims.lpl.arizona.edu Cassini Visual and Infrared Mapping Spectrometer website.

LaTeX (Document processing)

 

http://www.andy-roberts.net/writing/latex  Getting to Grips with LaTeX by Andrew Roberts.

Games

 

http://geoguessr.com - Geoguessr - Google Street View guess the location game.
http://locatestreet.com/game.php - similar
http://pursued.nemesys.hu - this one has a time limit.

http://inear.se/urbanjungle - Urban Jungle Street View.

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