int markPits(T& elevDEM, linearpart<float>& flowDir, std::vector<std::vector<node>>&islands, SparsePartition<short>& inc)
{
int nx = flowDir.getnx();
int ny = flowDir.getny();
int numPits = 0;
//There are pits remaining - set direction to no data
for (auto& island : islands) {
for (node flat : island) {
bool skip = false;
for (int k=1; k<=8; k++) {
if (dontCross(k, flat.x, flat.y, flowDir)==0) {
int jn = flat.y + d2[k];
int in = flat.x + d1[k];
if (!flowDir.hasAccess(in, jn))
continue;
auto elevDiff = elevDEM.getData(flat.x, flat.y) - elevDEM.getData(in, jn);
float flow = flowDir.getData(in, jn);
// Adjacent cell drains and is equal or lower in elevation so this is a low boundary
if (elevDiff >= 0 && flow == -1) {
skip = true;
break;
} else if (flow == -1) {
// If neighbor is in flat
// FIXME: check if this is correct
if (inc.getData(in,jn) >= 0){ // && inc.getData(in,jn)<st) {
skip = true;
break;
}
}
}
}
// mark pit
if (!skip) {
numPits++;
flowDir.setToNodata(flat.x, flat.y);
}
}
}
return numPits;
}
void flowTowardsLower(T& elev, linearpart<float>& flowDir, std::vector<std::vector<node>>&islands, SparsePartition<short>& inc)
{
long nx = flowDir.getnx();
long ny = flowDir.getny();
std::vector<node> lowBoundaries;
// Find low boundaries.
for(auto& island : islands) {
for(node flat : island) {
float flatElev = elev.getData(flat.x, flat.y);
for (int k = 1; k <= 8; k++) {
if (dontCross(k, flat.x, flat.y, flowDir) == 0) {
int in = flat.x + d1[k];
int jn = flat.y + d2[k];
if (!flowDir.hasAccess(in, jn))
continue;
auto elevDiff = flatElev - elev.getData(in,jn);
float flow = flowDir.getData(in, jn);
bool edgeDrain = flowDir.isNodata(in, jn);
// Adjacent cell drains and is equal or lower in elevation so this is a low boundary
if ((elevDiff >= 0 && flow >= 0.0) || edgeDrain) {
lowBoundaries.push_back(flat);
inc.setData(flat.x, flat.y, -1);
// No need to check the other neighbors
break;
}
}
}
}
}
size_t numInc = propagateIncrements(flowDir, inc, lowBoundaries);
// Not all grid cells were resolved - pits remain
// Remaining grid cells are unresolvable pits
if (numInc > 0)
{
markPits(elev, flowDir, islands, inc);
}
}
void setFlow2(int i, int j, linearpart<short>& flowDir, T& elev, SparsePartition<int>& inc)
{
/* This function sets directions based upon secondary elevations for
assignment of flow directions across flats according to Garbrecht and Martz
scheme. There are two possibilities:
A. The neighbor is outside the flat set
B. The neighbor is in the flat set.
In the case of A the input elevations are used and if a draining neighbor is found it is selected.
Case B requires slope to be positive. Remaining flats are removed by iterating this process
*/
int nx = flowDir.getnx();
int ny = flowDir.getny();
const short order[8]= {1,3,5,7,2,4,6,8};
float slopeMax = 0;
for (short k : order) {
int in = i+d1[k];
int jn = j+d2[k];
if (!flowDir.hasAccess(in, jn))
continue;
if (inc.getData(in, jn) > 0) {
// Neighbor is in flat
float slope = fact[j][k]*(inc.getData(i, j) - inc.getData(in, jn));
if (slope > slopeMax) {
flowDir.setData(i, j, k);
slopeMax = slope;
}
} else {
// Neighbor is not in flat
auto ed = elev.getData(i, j) - elev.getData(in, jn);
if (ed >= 0) {
// Found a way out - this is outlet
flowDir.setData(i, j, k);
break;
}
}
}
}
void flowFromHigher(T& elev, linearpart<float>& flowDir, std::vector<std::vector<node>>&islands, SparsePartition<short>& inc)
{
long nx = flowDir.getnx();
long ny = flowDir.getny();
// Find high boundaries
for (auto& island : islands) {
std::vector<node> highBoundaries;
for (node flat : island) {
float flatElev = elev.getData(flat.x, flat.y);
bool highBoundary = false;
for (int k = 1; k <= 8; k++) {
if (dontCross(k, flat.x, flat.y, flowDir) == 0) {
int in = flat.x + d1[k];
int jn = flat.y + d2[k];
if (!flowDir.hasAccess(in, jn))
continue;
auto elevDiff = flatElev - elev.getData(in, jn);
if (elevDiff < 0) {
// Adjacent cell has higher elevation so this is a high boundary
highBoundary = true;
break;
}
}
}
if (highBoundary) {
inc.setData(flat.x, flat.y, -1);
highBoundaries.push_back(flat);
}
}
propagateIncrements(flowDir, inc, highBoundaries);
}
}
//Calculate the slope information of flowDir to slope
void calcSlope(linearpart<short>& flowDir, linearpart<float>& elevDEM, linearpart<float>& slope)
{
int nx = elevDEM.getnx();
int ny = elevDEM.getny();
for (int j=0; j < ny; j++) {
for (int i=0; i < nx; i++) {
// If i,j is on the border or flowDir has no data, set slope(i,j) to slopeNoData
if (flowDir.isNodata(i,j) || !flowDir.hasAccess(i-1,j) || !flowDir.hasAccess(i+1,j) ||
!flowDir.hasAccess(i,j-1) || !flowDir.hasAccess(i,j+1)) {
slope.setToNodata(i, j);
} else {
short flowDirection = flowDir.getData(i,j);
int in = i + d1[flowDirection];
int jn = j + d2[flowDirection];
float elevDiff = elevDEM.getData(i,j) - elevDEM.getData(in,jn);
slope.setData(i,j, elevDiff*fact[j][flowDirection]);
}
}
}
}
long resolveFlats_parallel(T& elev, SparsePartition<short>& inc, linearpart<float>& flowDir, std::vector<std::vector<node>>&islands, linearpart<float>& orelevDir)
{
long nx = flowDir.getnx();
long ny = flowDir.getny();
int rank;
MPI_Comm_rank(MCW, &rank);
int numFlatsChanged = 0, totalNumFlatsChanged = 0;
flowTowardsLower(elev, flowDir, islands, inc);
do {
inc.share();
numFlatsChanged = propagateBorderIncrements(flowDir, inc);
MPI_Allreduce(&numFlatsChanged, &totalNumFlatsChanged, 1, MPI_INT, MPI_SUM, MCW);
if (rank == 0) {
printf("PRL: Lower gradient processed %d flats this iteration\n", totalNumFlatsChanged);
}
} while(totalNumFlatsChanged > 0);
// Not all grid cells were resolved - pits remain
// Remaining grid cells are unresolvable pits
markPits(elev, flowDir, islands, inc);
// Drain flats away from higher adjacent terrain
SparsePartition<short> higherGradient(nx, ny, 0);
flowFromHigher(elev, flowDir, islands, higherGradient);
do {
higherGradient.share();
numFlatsChanged = propagateBorderIncrements(flowDir, higherGradient);
MPI_Allreduce(&numFlatsChanged, &totalNumFlatsChanged, 1, MPI_INT, MPI_SUM, MCW);
if (rank == 0) {
printf("PRL: Higher gradient processed %d flats this iteration\n", totalNumFlatsChanged);
}
} while(totalNumFlatsChanged > 0);
// High flow must be inverted before it is combined
//
// higherFlowMax has to be greater than all of the increments
// higherFlowMax can be maximum value of the data type (e.g. 65535) but it will cause overflow problems if more than one iteration is needed
short higherFlowMax = 0;
for (auto& island : islands) {
for (auto& flat : island) {
short val = higherGradient.getData(flat.x, flat.y);
if (val > higherFlowMax)
higherFlowMax = val;
}
}
// FIXME: Is this needed? would it affect directions at the border?
short globalHigherFlowmax = 0;
MPI_Allreduce(&higherFlowMax, &globalHigherFlowmax, 1, MPI_SHORT, MPI_MAX, MCW);
for (auto& island : islands) {
for (auto flat : island) {
inc.addToData(flat.x, flat.y, globalHigherFlowmax - higherGradient.getData(flat.x, flat.y));
}
}
inc.share();
if (rank==0) {
fprintf(stderr,"\nPRL: Setting directions\n");
fflush(stderr);
}
uint64_t localFlatsRemaining = 0, globalFlatsRemaining = 0;
double tempdxc, tempdyc;
for (auto& island : islands) {
for (node flat : island) {
//setFlow2(flat.x, flat.y, flowDir, elev, inc);
orelevDir.getdxdyc(flat.y, tempdxc, tempdyc);
float DXX[3] = {0, tempdxc, tempdyc}; //tardemlib.cpp ln 1291
float DD = sqrt(tempdxc * tempdxc + tempdyc * tempdyc); //tardemlib.cpp ln 1293
SET2(flat.y, flat.x, DXX, DD, elev, inc, flowDir);
if (flowDir.getData(flat.x, flat.y) == -1) {
localFlatsRemaining++;
}
}
}
flowDir.share();
MPI_Allreduce(&localFlatsRemaining, &globalFlatsRemaining, 1, MPI_UINT64_T, MPI_SUM, MCW);
auto hasFlowDirection = [&](const node& n) { return flowDir.getData(n.x, n.y) != -1; };
auto isEmpty = [&](const std::vector<node>& i) { return i.empty(); };
// Remove flats which have flow direction set
for (auto& island : islands) {
island.erase(std::remove_if(island.begin(), island.end(), hasFlowDirection), island.end());
}
// Remove empty islands
islands.erase(std::remove_if(islands.begin(), islands.end(), isEmpty), islands.end());
return globalFlatsRemaining;
}
long resolveFlats(T& elevDEM, SparsePartition<short>& inc, linearpart<float>& flowDir, std::vector<std::vector<node>>&islands, linearpart<float>& orelevDir)
{
long nx = flowDir.getnx();
long ny = flowDir.getny();
int rank;
MPI_Comm_rank(MCW, &rank);
if (rank==0) {
fprintf(stderr,"Resolving flats\n");
fflush(stderr);
}
flowTowardsLower(elevDEM, flowDir, islands, inc);
// Drain flats away from higher adjacent terrain
SparsePartition<short> s(nx, ny, 0);
flowFromHigher(elevDEM, flowDir, islands, s);
// High flow must be inverted before it is combined
//
// higherFlowMax has to be greater than all of the increments
// higherFlowMax can be maximum value of the data type but it will cause overflow problems if more than one iteration is needed
short higherFlowMax = 0;
for (auto& island : islands) {
for (node flat : island) {
short val = s.getData(flat.x, flat.y);
if (val > higherFlowMax)
higherFlowMax = val;
}
}
for (auto& island : islands) {
for (auto flat : island) {
inc.addToData(flat.x, flat.y, higherFlowMax - s.getData(flat.x, flat.y));
}
}
if (rank==0) {
fprintf(stderr,"Setting directions\n");
fflush(stderr);
}
long flatsRemaining = 0;
double tempdxc, tempdyc;
for (auto& island : islands) {
for (node flat : island) {
//setFlow2(flat.x, flat.y, flowDir, elevDEM, inc);
orelevDir.getdxdyc(flat.y, tempdxc, tempdyc);
float DXX[3] = {0, tempdxc, tempdyc}; //tardemlib.cpp ln 1291
float DD = sqrt(tempdxc * tempdxc + tempdyc * tempdyc); //tardemlib.cpp ln 1293
SET2(flat.y, flat.x, DXX, DD, elevDEM, inc, flowDir);
if (flowDir.getData(flat.x, flat.y) == -1) {
flatsRemaining++;
}
}
}
auto hasFlowDirection = [&](const node& n) { return flowDir.getData(n.x, n.y) != -1; };
auto isEmpty = [&](const std::vector<node>& i) { return i.empty(); };
// Remove flats which have flow direction set
for (auto& island : islands) {
island.erase(std::remove_if(island.begin(), island.end(), hasFlowDirection), island.end());
}
// Remove empty islands
islands.erase(std::remove_if(islands.begin(), islands.end(), isEmpty), islands.end());
return flatsRemaining;
}
size_t propagateBorderIncrements(linearpart<float>& flowDir, SparsePartition<short>& inc)
{
int nx = flowDir.getnx();
int ny = flowDir.getny();
struct pnode {
int x;
int y;
int inc;
bool operator<(const struct pnode& b) const {
return inc < b.inc;
}
};
std::vector<pnode> queue;
// Find the starting nodes at the edge of the raster
//
// FIXME: oob access
for (auto y : {-1, ny}) {
for(int x = 0; x < nx; x++) {
int st = inc.getData(x, y);
if (st == 0)
continue;
auto jn = y == -1 ? 0 : ny - 1;
for (auto in : {x-1, x, x+1}) {
if (!flowDir.isInPartition(in, jn))
continue;
float flow = flowDir.getData(in, jn);
auto neighSt = inc.getData(in, jn);
if (flow == -1 && (neighSt == 0 || neighSt > st + 1 || -neighSt > st + 1)) {
queue.push_back({in, jn, st + 1});
// Here we set a negative increment if it's still pending
//
// Another flat might be neighboring the same cell with a lower increment,
// which has to override the higher increment (that hasn't been set yet but is in the queue).
inc.setData(in, jn, -(st + 1));
}
}
}
}
size_t numChanged = 0;
// Sort queue by lowest increment
std::sort(queue.begin(), queue.end());
std::vector<pnode> newFlats;
while (!queue.empty()) {
for(pnode flat : queue) {
// Skip if the increment was already set and it is lower
auto st = inc.getData(flat.x, flat.y);
if (st > 0 && st <= flat.inc) {
continue;
}
for (int k = 1; k <= 8; k++) {
if (dontCross(k, flat.x, flat.y, flowDir) == 0) {
int in = flat.x + d1[k];
int jn = flat.y + d2[k];
if (!flowDir.isInPartition(in, jn))
continue;
float flow = flowDir.getData(in, jn);
auto neighInc = inc.getData(in, jn);
if (flow == -1 && (neighInc == 0 || neighInc > flat.inc + 1 || -neighInc > flat.inc + 1)) {
newFlats.push_back({in, jn, flat.inc + 1});
inc.setData(in, jn, -(flat.inc + 1));
}
}
}
inc.setData(flat.x, flat.y, flat.inc);
numChanged++;
}
std::sort(newFlats.begin(), newFlats.end());
queue.clear();
queue.swap(newFlats);
}
return numChanged;
}