These Step-by-Step Instructions guide you through the Sketch Map Tool
and provide useful recommendations.
You can download and print this manual if needed.
Answers to the Frequently Asked Questions can be found in the FAQ
section below.
Learn more about the combination of the Sketch Map Tool with additional data collection
methods in the Additional Information section.
As the current version of the Sketch Map Tool has only been released very recently,
problems
might still occur during different steps of the process. We are sorry if this causes any
inconvenience for you! We strive to continuously improve the product, so kindly inform
us about the technical issues via GitHub
Issues.
Step-by-Step Instructions
1
Create paper maps to collect data
1.1 Define your Area of Interest
Select your area of interest either by zooming into the map preview or with
the
search function in the sidebar.
Choose from different paper formats and a suitable page orientation. The
dashed red line represents the boundaries of your area of interest, which
will
be printed on the Sketch Map.
Recommendations:
Adapt the extent of your selected area to your use case. The
following
questions should be kept in mind:
What should be mapped by the participants?
What should be visible on the map and in what level of detail?
Which areas should the map cover?
Adapt the area extent to the paper size you want to use.
The area is too big? Create multiple Sketch Maps.
Aspects you might want to consider for the selection of the area of
interest:
Ensure orientation on the map: streets (and their names) and
some landmarks should be visible. Besides visual inspection you
can check the landmark density result in the quality report.
Cover all relevant areas for your use case: e.g. if
studying
flooding,
cover especially those areas near rivers, creeks and sinkholes
as
well
as critical infrastructure which might be affected by the flood
event.
1.2 Map Quality Check
The generated Sketch Map uses a base map layer of OpenStreetMap
(OSM). The
Map
Quality Check helps to evaluate the OpenStreetMap data fitness of the area of interest for the
purpose of participatory mapping based on a quality analysis of the
OpenStreetMap data with the
HeiGIT ohsome quality analyst (OQT).
The
fitness
report can be downloaded as PDF file by clicking on the blue button. It
includes
an evaluation of the suitability of the local OSM data and recommendations
for
the subsequent field data collection.
Recommendations:
Before you use OSM based maps of your area of interest for
participatory mapping, please have a look at the results of the Map
Quality Check to ensure that participants can orientate properly on the
paper maps.
The analyses are focused on the landmark density, the
up-to-dateness of amenities and streets, as well as the
saturation of amenity and the road network mapping. You can learn more
about the analyses and each indicator in the generated PDF report.
The report includes useful recommendations to ensure that the generated
maps are suitable for participatory mapping.
In case the OSM data of your area of interest is not sufficient for the
purpose of participatory mapping, you can consult the Missing Maps project to
improve the OSM data before using the Sketch Map Tool. For example, you
could conduct a mapathon.
1.3 Export Sketch Map as PDF
The generated Sketch Map for your selected area of interest can be
downloaded as PDF file by clicking on the blue button.
THEN:
Data collection in the field
At the moment the Sketch Map Tool detects red, blue, green, yellow, turquoise
and pink markings. Red and blue markings work best in most cases. The detection
works best if the marked areas are filled out entirely.
Please make sure not to accidentally mark the globes on the edge as they are
needed to improve the automatic map detection.
Recommendations:
Use thick felt-tip pens with intense colours.
If you have many participants or you want participants to provide a lot of
different information, it is recommended to use individual Sketch Maps for
each purpose/topic or per participant.
Prepare the same set of pens for all participants/groups for better
comparison of the results.
Inform all participants that markings should be filled out entirely and
should not cover the globes on the edge of the maps.
If different colours are used for specific topics it is possible to let
participants include a legend for the meaning of each colour outside the
map extent. However, the tool currently does not use this information.
This needs to be done manually in the subsequent analysis process in
your Geographic Information System software.
If you collect additional information from the participants with other data
collection methods such as Kobo Collect or ODK, add a number on the Sketch
Map and save this number in the data collection questionnaire.
2
Paper to GIS: Automatically digitize collected data
2.1 Scan or photograph your marked
Sketch Maps
After the field data collection, scan or photograph the marked Sketch Maps.
The colour detection works best when scanning the Sketch Maps. When taking a
picture instead, make sure that the QR-Code is complete and that all globes
are visible on the image. The scans or photographs must be in jpg or png
file format for the upload to work.
Recommendations:
If you cannot scan, the photos must be taken from above in a 180-degree
angle (parallel above the Sketch Maps) to produce the best possible
result.
Please upload a complete image of the Sketch Maps and do not try to cut
out the map from the photo.
Take care of the lighting conditions when taking a picture.
The georeferencing works best if you scan the marked Sketch Maps with a
resolution of 300 dpi. Attention! The file size will be too large when
scanning with a 600 dpi resolution.
2.2 Upload your Sketch Maps
To upload files you can click on the upload field or drag and drop your
files directly in the upload field and then click on the Upload button. You
can upload one or more marked Sketch Maps at once. The upload works
for jpg or png files.
Recommendations:
It is possible to upload more than one Sketch Map at the same
time, but the upload will take longer.
If you are experiencing problems during the upload process, please check
out the FAQ section below.
2.3 Download collected Markings as
Geodata
You can download the georeferenced Sketch Maps as GeoTIFFs (zip) and the
colour-detected markings as vector data in a GeoJSON file.
The GeoTIFF raster data output files consist of georeferenced
images for each of your uploaded Sketch Maps.
The GeoJSON vector data output file contains polygons for the markings of
each
uploaded Sketch Map. Each polygon has attributes about its colour and its
source filename (from the uploaded image).
Recommendations:
If you are experiencing problems during the upload process, please check
out the FAQ section below.
FINALLY:
Import Geodata in a GIS, e.g. QGIS
You can load the vector data file into your GIS software. The layers have
different attributes (check attribute table) which correspond to the different
colours and file names of the uploads. You can also open the GeoTIFF file for
validating the colour-detection of the markings. The GeoTIFF output files consist
of georeferenced images for each of your uploaded Sketch Maps.
When you open the files in QGIS, it should look similar to this example and show
all the markings of your Sketch Map(s).
Recommendations:
In case some of the sketches have not been digitized correctly, you can use
the GeoTIFF file to manually create/adjust the polygon layers.
If the imported data looks strange and does not represent the actual
markings of the sketch maps, please check your uploaded sketch map files and
if necessary, scan them again or take new pictures according to the
recommendations above. Please review the recommendations
in the sections about the data collection, the scan or photograph and the
upload above and consult our FAQ section about the
problems in the colour
detection.
FAQs
What are OSM data?
OpenStreetMap data are freely accessible geodata. You can find out more about it here.
What are the quality levels for OSM data used in the tool?
The OSM data are classified with a traffic light system. Green stands for good
suitability of the data, yellow for possible problems when carrying out a Sketch
Maps
study with OSM based Sketch Maps, and red for probable problems. Recommendations
are
also given on what to consider based on the results.
Which analyses are performed and why?
You can read more about the analyses included in the Sketch Map Tool in this
paper.
Why is it important to analyse the suitability of OSM data before creating a
Sketch Map?
OSM data are used for the creation of the Sketch Maps. If the OSM data in a study
area
are lacking some important features, they are missing on the maps as well. Thus, the
quality of the OSM data is directly related to the quality of the Sketch Maps. The
features might be relevant for participants to orientate on the map.
For which research questions can the Sketch Map Tool be used?
The Sketch Map Tool has been primarily developed for research questions related to
floodings. But as the quality indicators used like the density of landmarks,
currentness of the data and data completeness are also important
in other use cases, you can also use it to investigate a completely different
research question, as long as you check that it fits your purpose.
How does mapping work with the Sketch Map Tool?
The local population can for example draw flooded areas such as streets, parks, etc.
on the printed Sketch Maps. The larger paper formats also allow to hold group
discussions about flooded areas. The maps with the markings can be photographed and
uploaded to the tool. The georeferenced TIFF and vector files can then be further
analysed or used.
How large can my study area be?
So far the Sketch Map Tool has only been tested on neighbourhood or city level.
The max. size of the study area is limited by the selection tool.
Why are there a QR code and globes on the Sketch Maps?
The QR code is required for georeferencing. The globes support the detection of the
map in your uploaded images. This is why it is important to have them on the Sketch
Maps.
Can I access my results at a later point of time?
No, the results should always be downloaded directly after using the tool. If you
forgot to download the files, you can simply upload and process the files again.
What do I have to pay attention to in the field?
Please make sure you do not accidentally mark the globes at the edge as they are
needed to improve the automatic map detection. But if someone accidentally marked
the globes, it is still possible to upload the Sketch Maps. Use thicker felt tip
pens with intense colours. Red and blue markings are best detected in most cases.
Prepare the same set of pens for all interviewers. Add a number on the Sketch Maps
and save this number in the questionnaire as well, if you use one. An overview of
each step with recommendations can be found here.
How does the georeferencing work?
You can find your answer in the
paper about the Sketch Map Tool
in the paragraph about 'Image Processing'.
What do I have to consider when photographing the Sketch Maps to get the best
possible results?
The images need to be in .jpg or .png format. All files together may not be larger
than 500 MB.
The georeferencing works best if you scan the marked Sketch Maps with a resolution
of
300 dpi. The photos must be taken from above in a 180-degree angle (parallel above
the Sketch Maps) to produce the best result.
An overview of
each step with recommendations can be found here.
How do I check if the georeferencing is correct?
You can open the TIFF file in a geographic information system (GIS), such as ArcGIS
or QGIS, to check this. If you load the file there and insert a basemap (for example
the OSM basemap) you can see if the georeferencing has worked. The Sketch Maps
should
match the base map.
Why does my generated TIFF file look strange?
Please first try to open the file in a geographic information system (GIS) such as
ArcGIS or QGIS. The georeferencing may have worked even if the TIFF file does not
look right. If it is still incorrect in the GIS, the map could not be properly
detected by the tool on the photo for which there are various possible reasons. For
example, the photo may have been taken from the wrong angle or the globes may have
been painted over.
Additional Information
In this section, we will shortly provide more details about how the Sketch Map Tool can
be combined with additional data collection methods. Stay tuned!