Digitizing II: CPH Features on floors

Introduction

For this lab, we'll add details of where features are located on the floors of the buildings. Visit the CPH Web Map and examine the data that has already been added. For this task, we be digitizing features that are on the floors of the buildings. You can use the buildings you used last week or take on additional buildings.

Digitizing indoors (or in canyons or underwater) is challenging as our electronic equipment (cell phones, GSP, etc.) does not tend to work well and we need higher accuracy than a compass can provide. The key is to have a map available of the area and then "draw" on the map. There are two ways of doing this, using a mobile device (cell phone or tablet) or a paper map. Your team can do either approach or both (part of QAQC is taking multiple approaches to a task and comparing the results). I recommend taking both approaches.

Editor Access to the Website

The new CPH map we've been creating is available at the URL below. Note that "?Editing-true" has been added to the URL. This is how parameters are passed into web pages on a server. The "Editing" flag will add a navigation bar across the top of the map and some additional buttons on the left side.

https://gsp.humboldt.edu/websites/CPHMap/CM2DMap.html?Editing=true

Click on the "Login" button and enter the username "student" and the password provided by the instructor. This will allow you to edit the contents of the map.

Warning: Please be careful making changes. There is backup of the map but everyone will be editing the same map data and if things get really messed up, we'll have to restore the entire map and we'll lose our changes. Also, only one person should be editing the features for one floor of a building at a time as the website does not yet arbitrate between multiple editors on the same floor.

The features that are displayed on the map are organized by "Feature Type" and then, within each FeatureType, by "FeatureSubtype". You can view these on the FeatureSubtype web page accessible in the navigation bar above the map on the website. Note that only some of the FeatureSubtypes appear inside buildings. You can sort to see these together using the "Sort By" option. Depending on the building floors you choose, you will only need to survey a subset of the FeatureSubtypes. You may want to bring a list of these with you when you survey the buildings.

Some of the features may be in rooms that are not accessible to everyone, please note these features when possible and give the best information you can.

Digitizing with a Mobile Device

Note that the software you will be using is in development and may have defects. Please take note of these as you find them and, if problems make it impossible to use the mobile device for surveying, fall back to the paper-based layouts.

To digitize interior features on a mobile device:

1. Navigate to the map in editing mode as described above.
2. Login using the "student" login and the password provided.
3. Zoom into and then click on the building you plan to survey.
4. Select the floor you want to survey. You should see any existing interior features on the map.
5. To edit the interior features, click on the layers icon and open the "Current Building" layer.
6. Click on "Floor Features" and you should see a an insert tool appear .
7. Click with the insert tool selected to add a new feature. Make sure to click in the floor.
8. Once added, you can use the select tool (an arrow) to click on the feature and move it around.
9. While the tool is selected, you can click on the attribute button to edit the features attributes.
10. With the attribute panel open, you'll want to change to FeatureSubtype. You should see the icon change for the feature.
11. You can also add a name and description if desired. The description could help users find features that might be somewhat hidden down a hall or under some stairs.
12. You'll want to regularly click "Save" to save your work and then refresh the map to make sure the changes were saved. The features for each floor are saved in a separate file so as long as only one person is editing the features for a floor at a time, you should not be able to overwrite someone elses feature edits.
13. To move a feature, just click on it and drag it to a new position. Zooming in on the map will help to position features correctly.
14. To delete a feature, click on it and open the attribute panel and then click on "Delete".
15. Do not change floors or buildings without saving your changes as they will be lost (I'll implement a dialog with "Do you want to save changes" but probably not in the next couple of weeks).

For this approach, this is all you have to do as the data will be saved in a "geojson" file on the server and will immeidately be available to everyone.

Paper Digitizing

Paper digitizing is simply using a paper based layout to draw the location of the feature and make notes about its type and if it has a name and if you want to provide a description. Then, in a GIS application, create a shapefile by digitizing the feature points on top of the georeferenced layout and adding attributes as shown below. Make sure to create the shapefile with the "Web Mercator" spatial reference so the coordinates match the map.

• id: -1
• name: empty or an appropriate name
• feature_subtype_id: see the FeatureSubtype web page
• building_floor_id: -1
• room_id: empty
• description: any additional information to help students with the specific feature

Then, digitize the features as you would any other point features by using the georeferenced layout as a background. Make sure to set the feature_subtype_id as defined on the website so the icons are correct.

If this looks a little strange it is because I changed the website to use a hierarchical files structure instead of a relational database over the summer. This made most of the entries optional. I'll probably remove them when I have a chance.

Note: Depending on the GIS application you use, you may only be able to enter 10 characters for the attribute heading. Just add those characters you can and I'll address the issue when I convert the file to geojson.

Additional Resources