The Step-by-Step Instructions will guide you through the Sketch Map Tool and provide useful recommendations.
You can also download and print the manual.

Answers to the Frequently Asked Questions can be found in the FAQ section below.

Here you can download the most important tips and questions for the mapping on one page.

Our new training platform provides five distinct training exercises to further explore the Sketch Map Tool and sketch mapping in general. These exercises are primarily designed for workshop settings, allowing for collaborative discussion of your experiences.

Since the latest version of the Sketch Map Tool was only recently released, you may encounter issues at various stages of the process. We apologize for any inconvenience this may cause. We are committed to continually enhancing the tool, so please report any technical problems to the Sketch Map Tool user support.

Step-by-Step Instructions

Create paper maps to collect data

1.1 Define your area of interest and choose a base map layer

The first step in using the Sketch Map Tool involves creating a printable Sketch Map.

Begin by selecting your area of interest, either by zooming into the map preview or using the search function in the sidebar. You can search for place names and coordinates. If you search for a location with coordinates please be aware of the correct structure, which is explained below.
Choose between the two different base map layers: one based on OpenStreetMap (OSM) and the other containing satellite imagery (ESRI world imagery)
Select from different paper formats and the appropriate page orientation. The dashed red line represents the boundaries of your area of interest, which will be printed on the Sketch Map.
Initiate the map creation by clicking the blue "next" button.

Searching by coordinates

Using coordinates to search for an accurate location is particularly useful in rural areas. Ensure that the coordinates are in the coordinate reference system WGS 84, expressed as latitude and longitude (LAT and LON).

Example: We have the following coordinates of Nairobi in WGS 84: 1.2921° S (latitude) and 36.8219° E (longitude). In the search field just type LAT, LON like shown below:

Be sure to include the hemisphere information (South/North, West/East) to avoid errors.

If you need to transform your available coordinates into Lat-Lon coordinates first, we recommend using this tool: Online converter to all coordinate systems

The marker of your searched point that appears during the map selection, will not be visible on the printed map. If you need this point as a point of reference on your paper Sketch Maps please mark it after you downloaded the PDF.

Screenshot of the searched point marked in pdf.

Recommendations

Tailor the extent of your selected area to suit your use case, keeping the following questions in mind:
- What do the participants need to map?
- What details need to be visible on the map, and at what level of detail?
- Which areas should the map encompass?
Aspects to consider when selecting the area of interest:
- Ensure orientation on the map: streets (and their names) and some points of interest (POIs) should be visible.
- Cover all relevant areas for your use case: for example, if studying flooding, focus on areas near rivers, creeks, sinkholes, and critical infrastructure that might be affected by the flood event.
- Choose a suitable zoom level: For example in case urban flooding it is recommended to generate a map on the neighborhood level with streets and buildings. For river flooding, it is recommended to generate a map for a larger extent.
Choose a suitable base map for your mapping needs. The decision between the OSM or satellite image base map depends on factors like your selected area, the quality of OSM data, your participants, and what you would like to map. Sometimes, especially if the satellite image is very dark (e.g., due to large forest areas on the map), it can be helpful to create two Sketch Maps with both base map layers: Satellite and OSM.
Customize the map format to fit your purpose:
- Group mapping is easier on larger maps (A2 or A1, depending on your group size).
- For data collection in the field, A4 or A3 are easier to handle. If the area is too big, consider creating multiple Sketch Maps.

If you like to learn more about the challenges of map orientation and how to choose a good base map, take a look at Training Exercise 2.

1.2 Map Quality Check

When you choose OpenStreetMap (OSM) as base map layer, you will be provided with a report on the map quality in your Area of Interest (AOI). The Map Quality Check gives an evaluation of the suitability of the local OSM data of your AOI for participatory mapping. The report is computed by the ohsome quality API of HeiGIT. The Map Quality Check can be downloaded as a PDF file by clicking on the blue button.

Recommendations

Before you use these OSM-based Sketch Maps for participatory mapping in your area of interest, review the analysis provided by the Map Quality Check to ensure that participants can orient themselves properly on the paper maps.
The analyses focus on Point of Interest (POI) density, the last edit of amenities and streets, used sources, as well as the saturation of amenity and road network mapping. Detailed information about each indicator and the analysis is available 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 in your area of interest is not sufficient for participatory mapping, consider the opportunity to improve the OSM data before printing the Sketch Maps, by organizing an OSM Mapathon. For more information and help on how to conduct a Mapathon please take a look at the Missing Maps project.
Take a look at the map:
- How well can you orient yourself on the map?
- Are important points of reference, such as hospitals, schools, landmarks, etc. visible on the map?

1.3 Export Sketch Map as PDF

The generated Sketch Map for your selected area of interest can be downloaded as a PDF file by clicking on the blue button.

Recommendations

Prepare separate maps for each topic or per person/group because it is difficult to read and analyze too many markings from one map. You can print out one map layout as often as you want.
We recommend printing the maps on matte, non-reflective paper.
Name your maps appropriately, a name on the downloaded and maybe as well on the printed Sketch Map can help you in organizing your maps. If you relate Sketch Maps back to questionnaires, use the same number for the map as you did in the questionnaire.
If you plan on printing out your map in black and white, check the visibility of the background map and reduce saturation in the printing settings if the background becomes too dark.
In case you use a satellite imagery background, please review the color saturation of your image. If the background is too dark, you might consider to choose OSM as base map or reduce saturation in the printing settings.

THEN: Data collection in the field

Mapping through sketches using a pen on a printed Sketch Maps is a core activity of the Sketch Map Tool process. How you mark the Sketch Maps influences your end results: the detected markings.

This section as well as this PDF discusses what you should keep in mind before and during mapping.

Example of marked Sketch Map:

Tips to improve marking detection

The latest version of the Sketch Map Tool leverages advanced Deep Learning models trained to analyze images of Sketch Maps and identify marked objects within them. Through supervised learning on extensive datasets of labeled images, these models acquire the ability to distinguish markings from the background of Sketch Maps by analyzing patterns and features. This enables them to accurately detect and differentiate markings. This predictive capability allows the models to generalize their understanding and accurately identify markings in new and unseen Sketch Maps. The Sketch Map Tool also incorporates conventional Computer Vision techniques to precisely position the Sketch Map within real-world coordinates. Georeferencing images entails detecting and matching specific points, such as the globes one the Sketch Maps, between the reference and current input image, enabling precise spatial alignment. Our current algorithm detects all markings, whether they are intended as a line, a point or a polygon as a polygon.

Please make sure to not accidentally mark the globes on the edge as they are used for georeferencing purposes in order to ensure the automatic map detection.

At the moment the Sketch Map Tool detects red, blue, green and black markings best, orange and yellow also work quite well. If different colors are used for specific topics, participants can include a legend for the meaning of each color outside the map extent. However, the tool does not support the identification of the written information or the matching of meanings to specific colors. This needs to be done manually in the subsequent analysis process in your Geographic Information System software. The GeoTiff can be used to manually match the geodata layer files to the legend information.

Picture of a Sketch Map. — **Original Image:** marked with red/blue polygons.

Result of Marking Detection. — **Result:** Closed circles are detected as one polygon and the whole area will be detected/filled by the software.

Recommendations

Line Thickness

Not recommended

Thin lines in light colors might not be detected. We generally recommend to test your pens and the detectability of your markings with the Sketch Map Tool before your mapping activity.

Polygon Outlines

Not recommended

Gaps in the outline could lead to mistakes in the detection.

Large polygons might not be detected properly.

If you just draw a line, the marked area of the line will be detected. Nevertheless, we do not recommend to use lines, since the model has not been trained to detect lines and doing so could lead to mistakes in detection of marking.

If you want to draw a point, draw a larger circle to improve the detection. If you want to draw lines, draw strong, non-dashed lines with intense colors.

Hint: If you need the marking as a line or a point shape, you can easily transfer it manually or digitalize it yourself, for example, in QGIS (see Training Exercise 4)

Satellite Base maps

Not recommended

Small polygons can be especially difficult to detected.

Tips for better comparability and interpretation of the maps

Map Orientation

Orientating on a map can be challenging, depending on the base map, the background of the participants, and their map literacy. Mapping in groups can make orientation much easier, as participants can assist each other in reading the map. Before you start with the mapping, we recommend:

Start by identifying a common place or points of reference.
Try to locate the current position or the place of residence of the participant on the map.

If you like to learn more about the challenges of map orientation and how to choose a good base map, take a look at Training Exercise 2. In Training Exercise 3,you can try mapping in groups in a role play.

Develop a mapping strategy

Prepare a clear data collection and analysis strategy beforehand. A consistent drawing or marking approach across different groups or individuals simplifies the comparison and analysis process, as the data is collected uniformly and its meaning is clear. For this, you should discuss and agree beforehand on:

What do you want to map?
Which colors should be used? For example, with blue, we map the area with the highest flood risk, and with red, we map safe places.

You should test your mapping strategy beforehand: Print out a map, draw some test objects with the pens you are planning to use. Upload the map and check if the result is satisfactory.You can practice the development of a mapping strategy in Training Exercise 3.

Organize your maps

Put a title on your map and add information about the participants, place and time to analyze the maps afterwards. Be careful; everything you write/draw on the map could be detected as a marked area (polygon), so use the white space outside the map extent.
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.
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.

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.

Examples

No Problem: Can be digitized properly

Problem: Missing or cut QR-Code
Without the whole QR-code the map cannot be recognized by the Sketch Map Tool.

Problem: Missing Globs and missing part of the map
This could lead to mistakes in the georeferencing and missing information on your map..

Problem: Tilted photos of the map
Can lead to mistakes in the georeferencing.

Recommendations

The photos must be taken from directly above, at a 180-degree angle (parallel to the Sketch Map), for optimal image quality.

For larger paper formats of a Sketch Map (E.g. A2) it can be more challenging to keep the map smooth and to take a proper photo. Easier than photographing from above by laying the map on a table or ground might be to pin or glue your map to a flip-board or a wall first and then take a photo.

Pay attention to the lighting conditions when taking a picture. If you experience problems with the results, for example the georeferencing failed or the markings where not detected probably, please take additional photos of your Sketch Map and upload them again. Small changes in lighting conditions and angels can make a difference! Additionally, you can consider compressing or resizing the original image to a minimum of 1024x1024 pixels before you upload your image.
The image of the Sketch Map needs to be uploaded as JPG or PNG (max. file size is 50 MB). The georeferencing and color-detection work even better if you scan the marked Sketch Map with a resolution of 300 dpi. Attention! The file size will be too large when scanning with a 600 dpi resolution.
If the marking detection does not work satisfactorily, you can improve the color contrast of the markings (with a pen, a new photo, or with photo editing software such as Paint, GIMP, or Windows Cut & Resize).
Name your scans/photos appropriately when saving, and before uploading them to the Sketch Map Tool. This helps you recognize and allocate your Sketch Maps in the subsequent uploading and analyzing process. If you relate Sketch Maps back to questionnaires, use the same number for the map as you did in the questionnaire.

2.2 Upload your Sketch Maps

To upload files, you can click on the upload field or drag and drop your files directly into the upload field and then click on the Upload button. You can upload one or more marked Sketch Maps at once. However, they all must be the same base map (same QR-Code), and the markings of all maps will be automatically combined in one GeoJSON. The upload works for JPG or PNG files. For one Sketch Map, it can take up to 100 seconds to produce a result, and for a package of 10 Sketch Maps, it can take up to 16 minutes.

Recommendations

If you experience problems during the upload process, please check out "2.1 Scan or photograph your marked Sketch Maps" above and the FAQ section below or contact your Sketch Map Tool focal point in your organization or the Sketch Map Tool user support

2.3 Download detected Markings as Geodata

Download the markings of the Sketch Maps in different geodata formats (raster data as GeoTIFF, vector data as a GeoJSON file). You can download the georeferenced Sketch Maps as a GeoTIFF (a georeferenced "picture" for each of your uploaded Sketch Maps) and the color-detected markings as vector data in a GeoJSON file.

Recommendations

If you experience problems during the download process, please check out the FAQ section below or contact your Sketch Map Tool focal point in your organization or the Sketch Map Tool user support if you cannot find your answers there.

FINALLY: Import Geodata in a Geographic Information System (GIS), e.g. QGIS

The gained geodata can be even more valuable for the communities and humanitarian organizations if you create result maps or analyze it further. There are many different analyses possible based on your gained map data.

To open, visualize and work with the downloaded geodata you need some type of GIS. We recommend using QGIS because it is open-source and provides the most flexibility for analyzing and visualizing your data. Alternatively you could also use browser based GIS-Applications like uMap. These browser-based applications are easier to use for beginners, but limited in their functionality. Please also keep in mind data security questions when using Online GIS-Applications for visualizing your data!

For more tips on how to open and analyze the downloaded geodata and how to create a result map in QGIS as well as in uMap, take a look at the following QGIS Training Lectures.

Here you can see an overview on the characteristics of GeoTIFF and GeoJSON and how the results could look like:

GeoTIFF

The GeoTIFF output file consists of a georeferenced "picture" for each of your uploaded Sketch Maps. When you open the GeoTIFF files in a GIS, it should look similar to this example and show all your sketch map(s) as separate layers. You can view only one of your maps at a time.

GeoJSON

If you open the GeoJSON, you can see the detected markings from all uploaded maps as polygons. When you check the attribute table, you can see that for each marking, the name of the map and the detected color are specified. With the help of these attributes, you can style your map or conduct analyses.

Recommendations

The GeoTIFF file (raster file) can be opened in a GIS software like QGIS but can not be opened in many browser-based GIS-Applications like uMap:
- It can be used, for example, as a background to combine it with other data or to manually digitize your results yourself in case some markings are not detected correctly.
The GeoJSON file (vector file) can be opened as well in QGIS as in many browser-based GIS-Applications like uMap:
- It can be visualized in a clear and concise map in order to use it for reporting (see Training Exercise 4)
- Based on the vector outputs you can analyze your data and combine it with additional data (e.g. prepare heatmaps, see Training Exercise 5 )
- In QGIS: You can compare the vector output with the raster file to verify the marking detection. In case features are not detected or are incorrectly detected, you can manipulate your vector file based on the GeoTIFF.
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. Please review the recommendations in the sections about the data collection, then scan, photograph or the upload above and consult our FAQ section about the problems in the colour detection. If you cannot find your answers there, please contact your Sketch Map Tool focal point in your organization or the Sketch Map Tool or the Sketch Map Tool user support.

Data storage and security

Map creation

Functionally necessary data storage: We need the original map frame to digitize your Sketch Map. The map frames of the created maps are stored for 12 months, giving you the opportunity to digitize your Sketch Map in those 12 months.

Paper to GIS

Functionally necessary data storage: Uploaded images of Sketch Maps are stored for processing (georeferencing and marking detection) until the results are generated.
The results are stored and available for download for a period of 24 hours, after which they are deleted.

On a voluntary basis, you can enable us to keep your uploaded Sketch Maps beyond processing to further improve the Sketch Map Tool.

If you opt-in by checking the check box you enable us to ...

... keep your uploaded Sketch Maps for future improvements of the Sketch Map Tool such as training our machine learning models which detect your markings on the uploaded images.

The Sketch Map Tool uses a sequence of machine learning models (SAM and YOLO) to detect the markings on the maps. These models need to be trained with a lot of real-world examples so they are able to identity the markings correctly.

Further accuracy improvements can be achieved by incorporating additional real-world cases of marked maps into the models. You can help us here by giving your consent!

For more detailed and technical information take a look at our GitHub and the following figure.

If you opt-out by leaving the checkbox unchecked (default) ...

... your uploaded Sketch Maps will be deleted after the results are generated. The results are stored and available for download for a period of 24 hours, after which they are deleted too.

Basic statistics

To get a better insight into the general usage of the Sketch Map Tool we store anonymous data about the map generation (date, centroid, layer, version, page format and orientation).

Questions and concerns

If you have further questions or any concerns please reach us via E-Mail.

It is also possible to set-up the Sketch Map Tool on your own server. In this case, please get in touch with the Sketch Map Tool team.

FAQs

What are OSM data?

OpenStreetMap data is freely accessible geodata. You can find out more about it here.

What are the quality levels for OSM data used in the Map Quality Check?

Based on the HeiGIT ohsome quality API, the OSM data used in the base map is classified with a traffic light system. Green stands for good suitability of the data, yellow for possible problems when carrying out a Sketch Map 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 this paper.

For which research questions can the Sketch Map Tool be used?

The Sketch Map Tool has been primarily developed for research questions related to flooding. Since then, it has been used world wide for a variety of topics like vulnerability and capacity mapping or risk mapping in general. You can use the Sketch Maps and the Map Quality Check to investigate all kinds of research questions, 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 Map. 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 GeoTIFF and GeoJSON can then be further analyzed or used.

How large can my study area be?

So far the Sketch Map Tool has only been tested on neighborhood or city level. The tool works best for study areas which are smaller than 50km².

Why is there a QR code and globes on the Sketch Maps?

These are required for georeferencing. The QR Code contains the ID of the reference map frame and the bounding box coordinates. The tool employs computer vision algorithms to match uploaded and reference map frames (mainly based on the globes) before it transforms and georeferences the uploaded Sketch Maps.

Can I access my results at a later point in 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 need keep in mind for the participatory mapping?

Please make sure not to accidentally mark the globes at the edge as they are needed for automatic map detection. Use thicker felt-tip pens with intense colors; red, blue, and black work best. Prepare the same set of pens for all interviewers. Here you can download the most important tips and questions for the mapping (summarized in a one-pager).

How does the georeferencing work?

Our georeferencing process employs the Binary Robust Invariant Scalable Keypoints (BRISK) method from the OpenCV library for feature matching. It begins by extracting bounding box coordinates and an identification number from a QR code on the uploaded Sketch Map to identify the corresponding unmarked reference map. Using the BRISK algorithm, the marked Sketch Map is aligned with the unmarked map. Later, we use the coordinates of the bounding box to transform the marked map into the world coordinate system (WGS 84), resulting in a georeferenced GeoTIFF file suitable for geospatial analysis.

You can find more details in the paper about the Sketch Map Tool in the paragraph about Image Processing.

How can I ensure optimal results when photographing the Sketch Maps?

The images need to be in JPG or PNG format. The file may not be larger than 500 MB. Georeferencing works best if you scan the marked Sketch Map with a resolution of 300 dpi. The photos must be taken from above at a 180 degree angle (parallel above the Sketch Map) to produce the best result.

How do I check if 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 upload the file there and insert a basemap (for example the OSM basemap), you can see if georeferencing has worked. The Sketch Map should match the base map.

Why does my generated GeoTIFF 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 GeoTIFF file does not look right. If it still appears incorrect in the GIS, the map might not have been properly detected by the tool in the photo, and there could be various possible reasons. For example, the photo may have been taken from the wrong angle or the globes may have been painted over.

What can I do if the satellite map I printed is too dark?

In case you use a satellite imagery background, please review the color saturation of your image. If the background is too dark, you might consider to choose OSM as base map or adjust the color saturation in the printer settings before printing.

How long are uploaded Sketch Maps stored?

The uploaded image(s) of your Sketch Map(s) will be stored on our server for processing (georeferencing and marking detection) until the results are generated. If you consent, the image(s) will be stored long term for future improvements of the Sketch Map Tool such as training our machine learning models which detect your markings on the uploaded images. If you do not give consent, the uploaded images will be deleted after the results are generated. The results are stored and available for download for a period of 24 hours, after which they are deleted too.

How much time do I have to upload the Sketch Maps for the digitization?

This is possible for up to 12 months after your maps have been created, after which the digitization will no longer work.

Step-by-Step Instructions

Searching by coordinates

Recommendations

Recommendations

Recommendations

Tips to improve marking detection

Recommendations

Line Thickness

Recommended

Not recommended

Polygon Outlines

Recommended

Not recommended

Satellite Base maps

Recommended

Not recommended

Tips for better comparability and interpretation of the maps

Map Orientation

Develop a mapping strategy

Organize your maps

Examples

Recommendations

Recommendations

Recommendations

GeoTIFF

GeoJSON

Recommendations

Data storage and security

FAQs