Hi SaikatM,

I wouldn't be too worried about mapping the riverbank of the Chobe/Cuando so precisely as what you see in the satellite imagery is only where the flowing water has kept the channel clear of floating reeds and vegetation, the actual river is far wider than this and will vary with the season and the prevailing wind and the age of the imagery, just compare different image providers and you will see what I mean. This applies to most the big rivers in this area, that flow through wetlands or flooded grasslands, the Zambezi, Kafue, Luapula, Chambeshi and Okavango will be similar.

Hi uliwanne,

Please be careful when mapping rivers that you don't break waterway relations when editing the larger river systems. also I know it is very difficult in this area because of the ridges and valleys but try get the rivers running in the correct direction, sometimes you have to zoom out and hide the data to get a better idea of the lay of the land. I actually compile a Garmin map from OSM data with elevation data to have a look at the correct river directions especially where rivers start on either side of a ridge and in the imagery it appears they are connected but are in fact not.

Have you every travelled to Bell Point in this area? It is well worth the trek but requires 4x4 and to travel in a group and I can assure you the road is a track.

I tend to tag all rivers as seasonal as they will only run in the rains and the smaller streams as intermittent as well as they will only run after a storm.

I suspect when the original district boundaries were created back in the day the act was more precise as per what you describe, Zambia recently created new districts and those are not as precise.

As regards the offset, Zambian maps use ARC 1950 Zambia as the datum and if you use WGS 84 on your GPS it will not correspond with the Ordinance Survey Maps, I personally know somebody who told a Zambian government surveyor that the Zambian maps were inaccurate, he felt a fool when the surveyor took his GPS unit and set the datum to ARC 1950 and hey presto it all lined up.

It would be interesting to be able to calculate the Bing offset for this region but suspect as new imagery becomes available the offset will be out of date, you see an offset at the border of two tiles from the same image provider sometimes and I have seen where mappers have put a kink in an obviously straight road because of the mismatch in imagery.

As an aside and off topic I would be interested in what you think regarding the tagging of rivers and streams in this part of the world. I consider all rivers here to be seasonal and some both seasonal and intermittent ie they will only run in the rains but even then only after a heavy rainfall, this is particularly true in the Valley and probably most of southern Zambia while in the north of Zambia they would slow to a trickle or less in the dry but generally flow all wet season so not intermittent.

Just a final word. If the Zim acts describing district boundaries are anything like the Zambian ones they can be a little vague with sections like "following a line in a south east direction to the junction with an unnamed stream and the Zambezi River, along this stream for 30 km and then in a north western direction for 50 km to a point just west of dambo X..." Where boundaries follow the course of braided rivers, of which there are many in western Zambia, this can be even more confusing. Add to that that the majority of mappers do not take into account imagery offsets and the differences in alignment between the images used, which in some cases is considerable for finer details and you can see OSM can never be considered "gospel".

Relax I just noticed the break on the OSM Inspector site http://tools.geofabrik.de/osmi/. My user name is only associated with the relation because I made edits to relations that overlap on the Zambian side and use the Zambezi as a common border, I try not to edit outside of areas I know and made no changes to the boundaries of the relation internal to Zim. There are a few remote German based users that make or have made edits to this region based on travels they have made here as tourists I presume. No need to send the act.

Hi Chris_Pakenham,

I think a recent edit of yours has broken the administrative boundary relations for the Kariba and Hurungwe.

Hi tytoalba••,

I notice you have tagged the woodland with leaf-cycle as evergreen, this is not correct, the correct tag would be deciduous as most trees in Zambia will lose their leaves towards the end of the dry season, a notable exception is the Winter Thorn (Faidherbia albida) https://en.wikipedia.org/wiki/Faidherbia.

As most satellite imagery of Zambia is taken during the dry season much of the woodland looks like scrub as the trees have lost or are losing their leaf canopy also owing to the very large bush fires that occur in the dry season the leaf canopy will be burnt off by the fires, this can be seen in some imagery and is the reason for the cut lines around the camp sites in Liuwa, to protect them. The fires are also the reason for the black appearance of many of the grasslands.

Please be aware when you are editing relations that you don't break them. You edited the riverbank relation of the Zambezi and tagged the outer ways as river, this was not correct and broke the relation. Please see the Wiki for an explanation of relations.

Hi I see you have changed the tag protected area to national park. See boundary=protected_area. It may be better to use protected_area with National Park in the protection_title tag. A national park is firstly a protected area then a national park. Also National Parks have different meanings in different countries.

Just a question, is somebody mapping in Spain mapping Europe or Spain? Just wondered as your comment "mapping africa" implies the whole continent rather than a small portion of one country in Africa

Hi,

The water features of this type in Zambia will be intermittent, they will dry up almost completely in the dry season, May to November. They are usually the lowest point in a type of seasonal wetland known as a dambo here and in Zimbabwe. During the wet season they may have about 30cm of water across the whole wetland, deeper in the lowest point that will last well into the dry season, the water in this point is known as a pan and is often a game water hole in the wildlife parks. During the dry season they are totally dry with plenty of tall dry grass that will burn fiercely and can be seen as really dark patches in some images, often mistaken for water and mapped as such by inexperienced mappers. I tend to map streams as both seasonal and intermittent as all rivers will technically be seasonal as we have a dry season and a wet or rainy season so the smaller rivers will not run in the dry season, the bigger ones will run with reduced capacity including the Zambezi. The really small streams may even only run after a rain storm and some years not even run at all hence the intermittent. Just some background for you.

Hi,
I Have moved your comment here as it applies to this changeset.

I do not think distance is relevant in classifying the way as secondary or tertiary as even tracks here in Zambia will travel great distances. I based my classification on the 'D' reference to the road in Zambia. Roads in Zambia are referenced 'T' (Trunk or primary), 'M' that I consider secondary, although there are some 'M' roads that are better considered primary as they are the main connecting roads, 'D' tertiary and there is also a 'B' which could be minor but better tertiary or unclassified.

I am not sure what the state of the Mumbwa - Kasempa road is at present but is probably used more as access to the northern end of the Kafue Park rather than a through route to Kasempa as the Kaoma - Kasempa road is better maintained and does not require crossing the Kafue by ferry/pontoon. The Kaoma - Kasempa road has, until recently, been maintained by the mining companies that transport south from Solwezi, cutting out the longer round distance route via the Copperbelt towns. As this is now the wet season and these are unpaved roads that may have all changed.

>Hi hello,
>I have changed the highway of >kesempa mumbwa to secondary as it >is more than 200 kms, do u agree with >me?

I agree with splitting the riverbank relation as per the wiki page. In fact this relation was originally created by another user sometime back who was insistent on being very precise, hence the very close nodes he left it in a broken state and I closed it. The problem with these wetlands and the floating vegetation is they can change daily not only seasonally, in Zambia it is fairly obvious in some of the imagery of different providers where switching between the images you will see large reed islands that have moved hundreds of meters especially as the prevailing winds change by 180 degrees. Another factor is some of the imagery is out of date by many years. This part of the world is affected by droughts that may last many years, the Selinda Spillway, usually flowing east from the Okavango, may not flow for many years and can reverse direction if the Zambezi floods heavily backing into the Chobe.

Some of the wetlands can be extremely large and if broken down and not named correctly will show confusing names on the map in a patchwork.The Okavango Delta for example has been maintained as one large relation since it was created 10 years ago (by yourself it would appear). I have kept your splits in the wetland has the Chobe/Kwando delta is only the delta shaped area not the whole wetland.

Hi,

I edited your edit to a toll booth as most if not all toll collection points are booths not gantries in Zambia. The type in SA are gantries as they register the toll automatically.

Hi,

Just to warn you, you have broken the wetland relationship here. Also you are mapping floating vegetation that is not permanent so pretty pointless

Having a closer look at your edit and then zooming out the channel is maintained by people in dugout canoes so they can get out to the low lying island out in the floodplain where there is a small settlement, probably a fishing village with some small gardens around it. The channel then extends toward a larger channel and then the main stream of the Zambezi. The local people here will travel great distances by dugout

Hi, Just a note to bear in mind when editing here, this is a large floodplain/wetland most "streams" are just open water channels in the reedbeds and would normally flow towards the Zambezi, so if you are mapping to the east of the Zambezi they would flow west or, as in this case, to the west of the Zambezi they would flow east. Nothing flows north, if it is not flowing east or west it will be flowing south but as I say most are just channels of open water not actual streams. and the open water may be temporary depending on how wet the season has been or at what time of the year the imagery is from.

HI Wisdom!!

I live in Lusaka. Imagery is not updated regularly in this part of the world. There is a lot of development here at the moment not shown in imagery.

Also waterway=riverbank is the the more common form of tagging for wide rivers see the wiki water=river?uselang=en-GB

Could you explain why you have changed the Kafue Flats from a wetland to a river?
This is a well known seasonal wetland in Zambia and is the floodplain of the Kafue river see https://en.wikipedia.org/wiki/Kafue_Flats.